Machinists Gazette

MISCELLANEOUS SHOP SUPPORT => Bench work => Topic started by: Carpenter84 on September 14, 2018, 12:20:57 AM

Title: Hand scraper
Post by: Carpenter84 on September 14, 2018, 12:20:57 AM
I'll kick off this forum section with the build of my hand scraper. Scraping is bench work afterall.

With me attempting to rebuild my lathe, it was prime time for me to finally learn how to scrape.
Ken was beyond generous to send me some scraper blades a couple weeks ago, I started building the handle for them tonight.
Used some stainless flat bar 3/16 x 1. The block turned out to be some kind of tool steel I had in a drawer, because when I brazed the pin in, I accidently hardened the block. Lol. Gonna be tricky to drill the countersink now... I'm copying an Anderson scraper handle style.

I put a pin in the setup to keep the clamp straight. Tomorrow I will get a countersink socket cap screw 1/4-28 and cut the chamfered countersink.

My co-workers in-law grandfather does wood turning. I may ask if he can fashion me a few handles, and maybe some file handles too.
Previously I was looking up Anderson scraper handles and by Anderson's chart, for my height, I need a 22" scraper. So, that's what I'll make. More than enough material here.
Title: Re: Hand scraper
Post by: 4GSR on September 14, 2018, 07:43:14 AM
Looking Good Shawn!
Title: Re: Hand scraper
Post by: woodchucker on September 14, 2018, 12:54:45 PM
Yea man.. looking good.
Now go make a nice handle and go practice.
Title: Re: Hand scraper
Post by: Carpenter84 on September 14, 2018, 01:51:22 PM
I've asked my workmate to ask his grandfather in-law. He does wood turning. I'm going to request a couple different handle types for the scraper and if he's willing a few file handles too.
Title: Re: Hand scraper
Post by: 4GSR on September 14, 2018, 02:33:53 PM
Go swipe the handle off your wife's good butcher knife and splice it on your scraper blade. ;D
Title: Re: Hand scraper
Post by: Carpenter84 on September 14, 2018, 03:00:53 PM
Pffff. She don't cook. I do. And I'm not ruining all my good knives.
Title: Re: Hand scraper
Post by: woodchucker on September 14, 2018, 03:02:55 PM
Pffff. She don't cook. I do. And I'm not ruining all my good knives.
Damnit your a carpenter, go make a handle for that scraper and get to work.   A rasp will make quick work, so will a block plane.... just getter done.
Title: Re: Hand scraper
Post by: Carpenter84 on September 14, 2018, 03:45:47 PM
As soon as someone invents more hours in the day... I will make my own handles.... No I won't, I'll just fill it with more work.... 🙄🙄🙄

It will depend on how long. If the old guy can pump out a few handles this weekend, fine. But if he's on old guy time and it's going to take 6 weeks, then forget it.
Title: Re: Hand scraper
Post by: f350ca on September 14, 2018, 05:05:55 PM
"But if he's on old guy time and it's going to take 6 weeks, then forget it."
Careful Shawn, I resemble that remark,

Greg
Title: Re: Hand scraper
Post by: Carpenter84 on September 14, 2018, 05:27:02 PM
Lol. Well, some guys are on top of stuff cause they enjoy it and some guys just like to sit around... Like my step-dad. He likes to do do woodworking too, but forget asking him to do anything. You'll be waiting for 6 months. Lol.

Turns out this guy enjoys it and he's gonna do it quick.
Title: Re: Hand scraper
Post by: Ulma Doctor on September 14, 2018, 10:26:07 PM
looking good Shawn!!! 👌

if you have a choice, make the handle broad so that you can put a pad on the rear of the handle.
you can put it against your body and really make metal fly when you put your hips into it.

the longer you make the scraper, the more sensitive it is.
i prefer longer scrapers myself, but you give up a little bit of the overall depth of scrape as a slight drawback
you'll never notice the difference by eye, but it can be measured (in ten thousandths of an inch)
Title: Re: Hand scraper
Post by: Carpenter84 on September 14, 2018, 10:58:48 PM
My workmates grandfather in law is making me two handles. Similar to the two pictured below. I'll make them interchangable. I remember reading that someone wished they could have a different handle for different steps.
Title: Re: Hand scraper
Post by: 4GSR on September 15, 2018, 06:09:53 PM
Here's a picture of my modified Sandvic scraper. That is a disc pad holder about 4" OD.  This one came from Horror Freight, I bet your Princess Auto has them over in the body repair section of the store.  Just wish mine was about 3-4" longer.  Mine will do for now.  I'm retiring from this stuff once I get Bambam's saddle done for him. :(
Title: Re: Hand scraper
Post by: Carpenter84 on September 15, 2018, 06:28:00 PM
Why?? Why retire this stuff?
Title: Re: Hand scraper
Post by: 4GSR on September 15, 2018, 08:15:15 PM
Just saying.  My old body has a hard time dealing with doing this type of stuff.  Doctor did put me on a pill the other day that is helping.  I may need to move up to Canada so I can cash in on some of that good stuff yaw have up there now. ;D
Title: Re: Hand scraper
Post by: Carpenter84 on September 15, 2018, 08:45:52 PM
Oh yeah... It's sooooo much better up here.
Title: Re: Hand scraper
Post by: 4GSR on September 16, 2018, 01:50:37 PM
Shawn, I ran across a magazine that I have called "The Home Shop Machinist".  Starting with the May/June 2011 issue, there is a article written on "Scraping for the Home Shop".  It continues for three more issues ending with the Nov/Dec 2011 issue.  You can buy the back issues of this series if available from the Village Press for a nominal fee.  I wasn't able to access it today, maybe not available on weekends, I don't know.  May have to call them during the week and see if you can get the magazines or at least a copy of the articles.

Ken
Title: Re: Hand scraper
Post by: dlane on September 16, 2018, 03:07:19 PM
Don’t have to go to Canada for that Ken, Cali 1st and Colorado 2nd, not that I would know  8)
Title: Re: Hand scraper
Post by: 4GSR on September 16, 2018, 03:48:01 PM
Don’t have to go to Canada for that Ken, Cali 1st and Colorado 2nd, not that I would know  8)

OoooKkkkkAaaaYyyyyy.

I don't want to know that.  We'll let Shawn decide.  8)

I could scan what I have and PM it to him. May have to have his email address for that.  I dare not post it. ???
Title: Re: Hand scraper
Post by: Carpenter84 on September 16, 2018, 05:42:06 PM
Oh Christ... I actually had nooo idea what you gentlemen were referring to... Lol. I don't partake.
But it's not legal yet...

Ken, I'll have a look for those mags. I am aware of the home shop machinist. I buy them when I see them in store.

...
I found the magazine's. I was able to get I to the village press store from an alternative link. The TEN part scraping series is spread over 8 issues. However, I cannot find part 1..
Also, that's $72 American, before shipping. They'd likely be $150 or more to my door... Any other suggestions?
Title: Re: Hand scraper
Post by: 4GSR on September 16, 2018, 05:59:53 PM
Contact Village Press and see if they will sell you just a copy of the article.  If you don't have any luck, PM me and I'll see what I can do.  At least for part one.

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on September 16, 2018, 06:01:41 PM
Oh, that's a good idea.
I tried a lengthy Google search for machinery rebuilding and scraping books, but came up dry.

I know there's a book Richard promotes, but I don't remember right now.
Title: Re: Hand scraper
Post by: Carpenter84 on September 16, 2018, 06:11:15 PM
Emailed.
Title: Re: Hand scraper
Post by: Ulma Doctor on September 17, 2018, 09:20:26 PM
Hi Shawn,
if you PM me you email, i'll send a copy of Connolly's book on machine rebuilding
Title: Re: Hand scraper
Post by: 4GSR on September 17, 2018, 10:29:26 PM
Shawn, along with Mike's offering, if you want me to email a copy of the article, send me your email, too.
Title: Re: Hand scraper
Post by: Carpenter84 on September 17, 2018, 10:33:56 PM
Gerritv beat Mike to the punch on Connell's book. I'm am very thankful for their gracious offers. I emailed home shop machinist, I got an email reply today. the cost for the ten part article would actually be more than if I bought the old whole issues. So, nuts to that.
If you have the article readily available, ken, I'd be happy to have it! You have my email, but I'll send you an email right now for you to simply reply to.
Title: Re: Hand scraper
Post by: Carpenter84 on September 21, 2018, 10:23:48 PM
I don't have a handle to my scraper yet, but in my bench vise, I find I don't hold the end of the scraper anyways. The bench vise elevates the work piece quite high, allowing me to choke up on the scraper and put a decent amount of pressure into it and use my body for the motion.
I have not tried the spotting blue yet, I don't have a method to spread it out on the surface plate yet. And my garage is still a total disaster from trying to out cabinets up. I got half way done and haven't had the time to finish.

Hoooowever, from a previous test with a sharpie marker, I know of a significant high spot on the dove tail. So, I took a swing at it with the scraper. Getting a feel for the motion and what not... This is gonna take some time to get comfortable with...
Also, I started on the wrong piece. I need to start on the female side as I was able to surface grind everything flat and parallel. I'll scrape that side and spot it till flat, then scrape the opposing surfaces till flat, then move into the dove tails.
I think that seems to be the logical progression.

I doubt I'll have much time in the coming days again. We have a wedding to go to tomorrow and Ashlees grandfather died tonight. So, it's gonna be a busy weekend/week. The wedding is a granddaughter of the diseased. So, tomorrow will be... different...  Bad timing.
Title: Re: Hand scraper
Post by: Ulma Doctor on September 22, 2018, 12:45:36 PM
Hey Shawn,
you can apply the spotting blue to a rag (lint free rag if you got it) and dab the surface plate with the rag at regular intervals, leaving a thin film of blue.
you can also spread it by your fingertips. it takes forever to do but it can be done.

a brayer is the best tool to get even coating of the surface plate
Title: Re: Hand scraper
Post by: Carpenter84 on September 22, 2018, 01:05:10 PM
It also doesn't help that the bench and plate currently look like this... Which is the main reason I haven't done anything yet. But I finally have all the cabinets up, so I can start putting everything away to clean the benches off and get back to the actual task at hand.
Title: Re: Hand scraper
Post by: 4GSR on September 22, 2018, 01:27:47 PM
Darn, that looks like my kitchen! :-[
Title: Re: Hand scraper
Post by: woodchucker on September 22, 2018, 04:42:18 PM
I don't see no stinkin plate under there. Holy Shit, that's a lot of junk..
And Ken, if that looks like your kitchen you better have all your shots up to date.
Title: Re: Hand scraper
Post by: 4GSR on September 22, 2018, 05:29:42 PM
I don't see no stinkin plate under there. Holy Shit, that's a lot of junk..
And Ken, if that looks like your kitchen you better have all your shots up to date.
;D ;D ;D
Title: Re: Hand scraper
Post by: Carpenter84 on September 22, 2018, 05:33:54 PM
Haha. I was thinking something similar.

I used to have shelves on that wall. I had to empty them to put the cabinets up.
Title: Re: Hand scraper
Post by: 4GSR on September 22, 2018, 05:53:45 PM
Is that now a weight bearing wall? ;)
Title: Re: Hand scraper
Post by: Carpenter84 on September 22, 2018, 07:52:25 PM
Load bearing? Haha. There are a LOT of screws in those cabinets now to make sure they never fall down
Title: Re: Hand scraper
Post by: Carpenter84 on September 22, 2018, 11:57:03 PM
Okay... Let's get on with this.


And let this be a lesson to you... animals! It IS possible to clean those benches! Now, go get it done!
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 12:05:39 AM
It wasn't terribly difficult to get the blue rubbed around with a paper towel. For these first roughing scrapes I assume this method will be acceptable. Once I get a lot closer I assume I'll need to keep things thin, clean, and smooth. I'll get a brayer this week.
I'd also like to get a .0001" dti, but for now my .0005" mitutoyo will suffice. Maybe Christmas.
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 01:32:36 AM
Ok. That's enough for tonight. My back hurts.
Title: Re: Hand scraper
Post by: gerritv on September 23, 2018, 06:16:08 AM
That's a big difference, both the benches and the scraping.
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 08:42:38 AM
Shawn,

For a starter that looks darn good.  Looks like your getting the hang of it.

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 08:46:16 AM
Anything to point out, ken??

Just getting a feel or technique has been tricky so far. Keeping the scraper flat and getting the scrape mark exactly where you want it. I feel there’s quite a bit of back and forth because sometimes I “miss”.
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 11:15:25 AM
Yeah, there's a lot of back and forth until you get to a point where you get at least 90% contact from end to end.  The other thing is getting your points per square inch.  I usually call it good once I get around 12 PPI.  I have reason for that, not trying to get 20-30 PPI, just not needed on hobby stuff.
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 01:34:02 PM
Okay. So nothing standing out to you that would be an issue yet?
I'm not done this one yet, this is just where I stopped last night at 2:30 in the morning.
Ashlee messaged me last night at like 1 to tell me I was being too noisy. Lol 🙄 I said bollocks, I'm making zero noise. Unless SOMEHOW you can hear the sound of me scraping... Yeah right... Lol
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 02:22:04 PM
Continue.  Don't let me stop you and progress~!!!
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 04:22:15 PM
Wasn't suggesting you were. Just looking for critiquing. I have nooooooo idea what I'm doing...
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 04:47:52 PM
Wasn't suggesting you were. Just looking for critiquing. I have nooooooo idea what I'm doing...

I don't either....
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 05:02:54 PM
I haaaaave to imagine you know more than I know. Lol. So far you've known everything I've asked. Lol.

Alright alright. I'll stay the course.
I'm a smart guy. Lots of this stuff is common sense. As long as I can approach this without noob blinders on, I'll figure it out.

I'm not looking forward to the dovetails...
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 07:19:39 PM
On the dovetails, stand the part up on edge, holding it with some kind of simple fixture. Wood works great.

On the inverted vee's like on the carriage, make a fixture set at a 45 degree angle to hold the saddle.

Yeah, I find with people I've trained over the years, feed them a little bit and see how they do.  Kind of like hanging a carrot in front of the horse.  Most of the time they catch on.

Your doing fine Shawn,

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 07:50:08 PM
😀👍
Title: Re: Hand scraper
Post by: ddickey on September 23, 2018, 09:06:34 PM
The way oil film on the ways must take up some difference between surfaces.
Anyone have an idea how much?
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 09:28:46 PM
I think I'm going to stop here with this part. I know the base of the compound is going to be a chore. It's quite bad.
I also cobbled a 1" hole from some aluminum sheet metal to count PPI. I traced a 123 block with a knife, and kept scoring until it cut through.

Ken if you go for 12 PPI, this is already higher in most places. So I think I'm happy. Getting the hang of it.

Now that I've got my feet wet, I'll go back and watch Richards video again, from 1979, and maybe I'll gather more useful information that is may have missed from last time. Maybe I won't find it so disappointing.
I haven't even cracked the Connelly book yet. I think a book that big scares me! I barely have enough time to work out here. Any time I spend reading, is time lost practicing.
But I think I've created a very good starting point to move forward.

Onward.
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 09:33:53 PM
And as far as the surface plate goes. Instead of trying to find a bigger one and spending a lot of money, I think even just getting a second one of these B grade 12x18's, at $60 from busy bee, will help. If I can devote one whole plate to bluing, I can use the other plate for indicating etc.
That won't help me with the milling machine, but I'm not anywhere near ready to pull that pig apart again. Maybe by then I'll have found a good deal on a 24" plate.
Title: Re: Hand scraper
Post by: 4GSR on September 23, 2018, 09:53:58 PM
If you are going to get another surface plate, get at least a 18 x 24.  I have two, and a smaller cast iron plate for bluing. I can check the C.I. one against one of the granite one's for reconditioning when needed.  Also by the time you put a set of vee blocks on the plate and a height gage and surface gage, that 12 x 18 gets crowded very quickly.

The Connley book is a great reference on alignment of machine members and how to adjust your scraping for utmost accuracy out of a machine.  It covers little on scraping as the author assumes that you already have the basics of scraping behind you.  Which means you are ready to read the book.

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on September 23, 2018, 11:19:14 PM
I have no idea where to find a bigger plate locally, that’s not hundreds and hundreds.
Title: Re: Hand scraper
Post by: gerritv on September 24, 2018, 06:33:58 AM
I have no idea where to find a bigger plate locally, that’s not hundreds and hundreds.

KBC Tools (http://kbctools.ca), CA$147. There is also an ad in Kijiji for surface plates, looks like the ones we were looking at before (the guy who was never available when I was). Stoney Creek so just up the road from me.

Gerrit
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 06:39:44 AM
If I'm asking my wife to buy it for Christmas it has to either be able to be ordered online, or a reasonable store for her to go into. I've offered to set something up from a wholesaler before and she wouldn't go in. Lol. I guess it's somewhat intimidating? I'm in various wholesalers every day, it's nothin to me. Most of the time they're like candy stores for me.

I recently set up an account with Fastenal, I emailed the guy there about some Sterrett plates and a mitutoyo .008" dti. I'm sure both will be wildly expensive. But we will see. I inquired about a 18x18 and a 18x24 plate. The 18x24 is a 6". That's a heavy plate...

I WAS going to do the Stony Creek fiasco. I even made arrangements. But had to back out for some reason. Can't remember.
Title: Re: Hand scraper
Post by: gerritv on September 24, 2018, 06:53:17 AM
3" 18x24 is 147 lbs, I would check KBC to see what shipping would be :-) Likely much less than Fastenal pricing.
Title: Re: Hand scraper
Post by: 4GSR on September 24, 2018, 07:22:43 AM
The way oil film on the ways must take up some difference between surfaces.
Anyone have an idea how much?

The low areas are usually about .0002" deep.  Really good scraper millrights can lay them down where there is over .001" deep.  I don't recommend the lows being any deeper than about .0005".  I think this is about what Richard preaches in his classes.
Title: Re: Hand scraper
Post by: 4GSR on September 24, 2018, 07:28:32 AM
................................................The 18x24 is a 6". That's a heavy plate..............

My Starrett pink granite 18 x 24 x 6" thick and no joke, it is is heavy!  I have not had it calibrated, new, I'm pretty sure it was a A grade plate. Somebody before me ripped off the calibration tag with it's serial number before I got it.  Still has the Starrett label though.

Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 09:52:53 AM
Just won this on eBay. Made an offer that was accepted. $30.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F352461833599

Says they're just cracked lenses. I'm fine with that... We will see.
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 09:57:00 AM
Haha. Those pink Sterrett plates are near and over a grand from Fastenal... Yup...
Title: Re: Hand scraper
Post by: 4GSR on September 24, 2018, 11:14:56 AM
Yeah, by the time I paid shipping to my workplace at the time, it was half off that!  And still a lot of money to me.

I'm kind of in the same boat as you are in a way.  For me to find good bargains or even new stuff, it has to ship in from up north.  By the time I get it, shipping cost can get as high as what you paid for the item.  I have Fastenal down here too, but they are the last person in town I'll go to to buy anything from.  I would shop around, something will pop up close by.
Title: Re: Hand scraper
Post by: ddickey on September 24, 2018, 01:43:53 PM
The way oil film on the ways must take up some difference between surfaces.
Anyone have an idea how much?

The low areas are usually about .0002" deep.  Really good scraper millrights can lay them down where there is over .001" deep.  I don't recommend the lows being any deeper than about .0005".  I think this is about what Richard preaches in his classes.
The ways are supposed to ride on an oil film, correct? So you're saying if the way surface is flat to with .0005" that is acceptable? Not sure what you meant by the millwright comment.
Title: Re: Hand scraper
Post by: 4GSR on September 24, 2018, 02:02:21 PM
It should ride on a oil film of about .0005".  What I was referring to, is when you scrape, the scrapings have a depth of about .0002-.0005" deep.  So when you are done, the "high" or "blue spots" metal, is your bearing surface, and the "low" metal or no marking, will retain oil for lubrication, in theory, and in fact really works. 
Title: Re: Hand scraper
Post by: Ulma Doctor on September 24, 2018, 07:03:38 PM
you are looking good Shawn on your scraping!
nice work.

i did notice that you have more contact in the upper portion (as pictured) of the dovetail flat
it's not a big deal, but the side that has less contact area will wear faster than the other sections.
ideally you'll have somewhere between 40 and 60% contact (blue) @ 10 to 30 PPI - primarily dependent on the specification and/or the skill of the scraper.

not trying to discourage here, more like offering a friendly advice  :)

you may find the .0001" DTI to be annoying on your first venture, i'll imagine.
they bounce around a whole bunch in operation until you are almost dead flat.
you may wish to purchase or use a simple dial indicator until you are within .001"
when you are done with the .001" dial indicator ,then you nitpick with the DTI

all in all you are doing just fine, keep doing until you don't think about it anymore-
then you'll know you got it!!!  😎
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 07:31:53 PM
Mike, thank you for the comments. Don't for a second think you are discouraging me. I NEED this critiquing. I welcome it. I enjoy the tips.

I DO see now what you are talking about. I was looking at PPI but I neglected to notice the negative space, the low spots. You're right. These sections would wear out quickly. I will attack these flats some more. I picked up some yellow artists oil paint, I'll try it as a highlighter paint. I didn't really have a hard time seeing the blue, but worth a try.

I picked up the .0001 to complete my set. I have a few dial indicators, and a mitutoyo .0005 dti, now the .0001 federal coming. I wanted it to better give the measurements a number.  With the .0005 it's difficult to properly give the section I'm measuring an actual number. It's like trying to guess the hundred thousandths with a non verneer micrometer. You can guess close, but I prefer to actually have a line and a number over just a line between lines. Just me being nit-picky.

Thanks for the help guys. Please keep it coming.
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 09:47:40 PM
I bought a brayer. Gave it a try.

Incredible!! Look at that contact surface! It's almost like a million PPI!!



....

I obviously have to work on my fluid thickness. 🙄🙄🙄
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 09:48:00 PM
The blue on the scraped surface is kind of pretty tho.
Title: Re: Hand scraper
Post by: Carpenter84 on September 24, 2018, 09:51:48 PM
Better. I don't have time tonight to scrape more. I'll leave this like this till tomorrow maybe. Try to get a bit higher PPI and better contact %
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 06:42:15 PM
looks good!
as you go forward, you'll use less and less ink on the blue ups.
the points will start being a little more difficult to see.
at that point, you can rub the blued up surface of the scraped part onto a bare part of your surface plate.
in the center or the blue islands you will see polished looking points with no ink on them, those are your very highest points and the true indication of actual contact.
your are going for relatively large islands with spaces in between for trapping oil.
the theory is that you can't compress a liquid, if you captivate oil in a small space- it acts like a big bearing, and also reducing the friction between the 2 planes
Title: Re: Hand scraper
Post by: Carpenter84 on September 25, 2018, 06:55:33 PM
Yes, I was polishing the high spots to see how big they actually were. So, I want bigger islands with some space around? Or lots of islands?

Edit: I re-read that. Yes, bigger islands with space around to trap oil. Got it.
To achieve that, am I at the point where I'm knocking down the high spots still?
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 07:02:42 PM
both if you can swing it.
the larger the islands are the more weight they can support before they wear away.
the more islands there are, the more weight the entire assembly can carry before it wears
i would think that a 50-50 would be optimum.
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 07:06:02 PM
your flat looks pretty good at this point.

i would take some measurements of the 4 corners, then in the middle and see how flat you are on the opposing surface.
then you may consider how much may need to be taken of the first side to keep geometrically correct.
i wouldn't go too crazy over a thousandth at this point
Title: Re: Hand scraper
Post by: Carpenter84 on September 25, 2018, 07:47:55 PM
Awesome. Thank you, Mike.
I won't have time tonight probably. The wife is on several weeks of extremely early mornings at work and I drive her. So, my midnight scraping sessions will have to take a back burner till the weekend probably.

But, to clarify. What are my scraping techniques now? I've been done with the Z's for a while and dive bombing. Should I be knocking down high spots only - dive bombing, I guess Richard calls it - or just doing evenly spaced scrapes? Or?
Title: Re: Hand scraper
Post by: 4GSR on September 25, 2018, 08:14:32 PM
Mike, you did a great job explaining the "hills" and "valleys" to Shawn.

Thanks,

Ken

We might make a scraper hand out of him yet! ;D
Title: Re: Hand scraper
Post by: Carpenter84 on September 25, 2018, 09:08:31 PM
Lol. Someone answer what I do next!!
Title: Re: Hand scraper
Post by: 4GSR on September 25, 2018, 09:36:38 PM
Lol. Someone answer what I do next!!

Take the night off! ;D
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 10:21:16 PM
Mike, you did a great job explaining the "hills" and "valleys" to Shawn.

Thanks,

Ken

We might make a scraper hand out of him yet! ;D
he's well on his way already! 👌👍
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 10:23:18 PM
Lol. Someone answer what I do next!!

Hi Shawn,
you really should do the measurements as your next step
otherwise you are only scraping to scrape.
if you know where to scrape and why to scrape there, you would be getting more of the overall picture
Title: Re: Hand scraper
Post by: Carpenter84 on September 25, 2018, 11:10:07 PM
I indicated it. With my .0005 mitutoyo dti, I cannot see any discernable difference. The needle jumps around what I can only assume is about .0002 in the high/lows. all 4 corners look the same. I need to surface grind the top side again tomorrow. The flat infront of the tool holder t-slot is about .0003 low. When I indicate the dovetail flats I can push down and rock the compound back and forth making it difficult to get an accurate reading.

Also, I'm fed up with this small plate. I'm going to busy bee and buying another 12x18. They're dirt cheap and close to home. The big ones I found on Kijiji are over 2 hours away. Not convenient right now. I need a second plate for just rubbing blue and the other for indicating and polishing the blue.
I've been trying to split the plate in half for blue and polish but it's just working.

When I polish the flats I'm getting better contact % than I was before. Now it just looks messy, but I'm donnnne with this half. I'm sure I'm just chasing my tail at ridiculous tolerances. I'm going to start rough-in in the mating bottom section.
Title: Re: Hand scraper
Post by: Ulma Doctor on September 25, 2018, 11:15:06 PM
if the part is rocking on the plate, you can try to fit feeler gauges under the end with the most clearance.
that will dictate how much you need to scrape off the opposite corner in order to get truly flat

Title: Re: Hand scraper
Post by: Carpenter84 on September 25, 2018, 11:46:12 PM
The scraped side is fine. It's the top side of the compound. The side that the tool holder sits. More specifically, the flat forward of the t-slot.
The thinnest feeler gauge I have is .0015", it does not fit under anything, anywhere. I assume thats a good sign.

If I indicate the top of the compound, the flat forward the tool post is about .0003 low. Not sure how or when that happened since I started all this by surface grinding both sides flat. Maybe the process of scraping introduced a taper. Either way, a quick lick on the SG should clean up that top side. Actually, when I'm done scraping, I was going to grind all the visible sides to clean them up. Make em pretty... Maybe...


Tomorrow is another day. I will start on the mating side and make some progress there. See how it all goes. I think I need to try to move forward and try to scrape in a mating surface. I'm less concerned with the compound as I rarely use it. But I like it on the lathe for when I do short tapers. The real test will be when I rebuild the cross slide. Which I'm sure will be a whole new can of worms... Not to mention eventually getting to the carriage and the ways... 😵😵😵
Maybe some time during the winter I'll get there. I'll need some kind of a straight edge at that point I imagine.
Title: Re: Hand scraper
Post by: 4GSR on September 26, 2018, 09:48:15 AM
Shawn,

One thing to keep in mind, the piece of cast iron you have there may have induced stresses in the material that are relieving them selves as you scrape on it, AND may even from grinding on the piece to begin with.  Now that you have one side reasonably flat, put that side against the chuck on your grinder.  Grab it on one end and scoot it side to side to see if it "hinges" on the magnetic chuck. It should hinge or pivot about a quarter to a third of the way from the end.  Try this on both ends.  Really, this should be done on your surface plate. Regardless, you should get that hinging of the part. If so, you are good, suck it down and regrind that surface flat. Should be all you need to do is dust the surface, maybe .002"at most, to get 100% cleanup.  Take a Sharpie and draw lines down the part, so you have a indicator that it cleaned up.
Title: Re: Hand scraper
Post by: Carpenter84 on September 26, 2018, 10:55:27 AM
I've been hinging all along this process. It's hinging perfectly.
But there is a curve in the piece. If I polish the highs for a long time I can get the high flats mirror smooth. You can see the mirrored high spots decline in brightness as you travel towards the center on both dovetail flats. And after 3 rescrapes on 1" of all 4 corners, it does not appear to be going away. So what you say about stress is showing itself. I imagine it's flexing at the thin spot - the base of the tool holder t-slot. But, we must be talking about incredibly minute amounts because all highs do polish to a degree, but like I said, you can see the varying degrees of polish as you move towards the outsides. I don't think there's anything I can do about that or worth doing anything about. The compound is flat enough that even on a thin layer of blue And without blue - just on the clean plate, it hinges 1/3 in on each side.
Title: Re: Hand scraper
Post by: 4GSR on September 26, 2018, 11:00:01 AM
Yeah, your playing with millionths there, call it good and move on to the mating piece and start scraping it against the one you just done.  Tackle the dovetails last.  The dovetails is where you need a scraping straight edge.
Title: Re: Hand scraper
Post by: Carpenter84 on September 26, 2018, 12:47:25 PM
Yeah, your playing with millionths there, call it good and move on to the mating piece and start scraping it against the one you just done. 

Yeahhhh... I already moved on to the other piece this morning the half an hour I had before work.

Tackle the dovetails last.  The dovetails is where you need a scraping straight edge.

And that's where I will hit a road block. I do not have a straight edge.
I have a big chunk of what I assume is ductile cast iron. It's a big chunk of a sewer housing. I've been meaning to put it in the mill and hog out a straight edge. Then grind it, and now that I'm getting more comfortable with scraping, get it scraped flat and 60°.  It's only about 6" long, so it'll work with the compound but not for much else.
Title: Re: Hand scraper
Post by: Carpenter84 on September 29, 2018, 10:13:20 AM
So it's cooling down up here. Only 15° today. The top of the compound blues up completely different now. It's bowing in the opposite direction .0002-3".
Also, while scraping in and bluing the mating part, it rubbed down the high spots, so now the islands are much larger, however, I can see I need to do some half moons or something because I can see my low spots aren't low enough.

The picture is pretty hard to make out. A lot of reflections going on in here.

Oh, and I caved and bought a second 12x18 plate for $65... I really just needed more room quickly.
Title: Re: Hand scraper
Post by: 4GSR on September 29, 2018, 12:59:21 PM
Scrape those blue areas, take impression and see if the pattern changes and report back.

Sounds to me like you have a piece of unstable cast iron there.  I think if you flip that over onto your SG and dust the top for 100% cleanup, then take a impression.  That will tell me more of whats going on.  Also when you flip it over on the SG, see if your .0015" feeler will go under any of the edges.  If it does, shim it with brass shim stock until it's snug. Then SG the surface.
Title: Re: Hand scraper
Post by: Carpenter84 on September 30, 2018, 12:03:24 AM
Ok. I'll try that tomorrow (today).

Also, I hogged this SOB out of that big gnarly chunk of sewer cast iron.
I'll scrape the bottom in, and the 45°, but how do I compare the two surfaces? Also, how do I blue the 45? It's not very big, and movement is limited on the edge of the surface plate.
I need to refine the shape a bit more, likely make it narrower. That step on the square side was removing a large broken off chunk in the middle. I may just square that off.
Title: Re: Hand scraper
Post by: 4GSR on September 30, 2018, 11:06:24 AM
I would take the 45 degree angle all the way up the part, so that way you have a way to mark it on your surface plate.
Title: Re: Hand scraper
Post by: Carpenter84 on September 30, 2018, 11:14:52 AM
That's a terrific idea. I was literally just playing with it wondering how the hell I was going to do anything with it at all...

I will hog the rest of that side off... Then I have MANY questions...
Title: Re: Hand scraper
Post by: Carpenter84 on September 30, 2018, 03:46:09 PM
Jeez. Talk about hard to hold .. nice and sketchy...

I hogged most of the 45 out.
Any tips on truing the 45° side with the bottom flat when scraping? Is it worth making those two sides true to each other? I have two sets of angle blocks, big and small, but I don't think they're worth a crap. Cheap. I'd have to fix them up better. And I don't have a sine plate or guage blocks.

How do I indicate the 45 to level it?
Title: Re: Hand scraper
Post by: 4GSR on September 30, 2018, 06:53:28 PM
Jeez. Talk about hard to hold .. nice and sketchy...

I hogged most of the 45 out.
Any tips on truing the 45° side with the bottom flat when scraping? Is it worth making those two sides true to each other? I have two sets of angle blocks, big and small, but I don't think they're worth a crap. Cheap. I'd have to fix them up better. And I don't have a sine plate or guage blocks.

How do I indicate the 45 to level it?

Don't need to worry about the 45 being level or square with the bottom.  Get as close as you can.  All you are interesting in is that each surface is flat. You're not supposed to use it to scrape a dovetail to it.  You only using the straight edge to scrape the dovetail flat.  Once that is done, then scrape the mating dovetail to mate with it.  Dig around the front of the Connelly book you have there.  Look at pages 59, 60, and 150 for examples.

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on September 30, 2018, 08:05:42 PM
K thanks
Title: Re: Hand scraper
Post by: Carpenter84 on October 01, 2018, 11:06:20 PM
How's this now? The straight edge I made.
I figured out why I couldn't get nice big islands before. The tool I was using had too shallow a radius. Ken, I started using the dovetail carbide you ground because it was the only one that gave me a smaller scrape. The other ones would scrape 3/16" wide.
I bought a diamond grinding wheel on eBay. I'll cobble together a carbide grinder. It's a 2000 grit. It was $8 from China. Should show up some time around June. Lol.

Anyways. The blue was a bit heavy on this one. The yellow artists oil paint I bought works quite well for highlighting.
I polished it on the other surface plate. Can't see it in the photo but lots of nice big islands with nice deep grooves around them.

I did a PPI count of the shiny highs. 27, 30, and 34.

What do you think? I know it's a bit bare around the edges...
Title: Re: Hand scraper
Post by: 4GSR on October 02, 2018, 10:08:11 AM
You're getting the hang of it. Learning the importance of the radius on the end of the carbide, too.  Your outer edges around the part are shallow.  What is up with that?  Are you honing too much on the edges? 
Keep up the nice work!
Ken 
Title: Re: Hand scraper
Post by: Carpenter84 on October 02, 2018, 11:14:34 AM
The edges might be a combination of stoning and accidently scraping off the edge. I don't have a handle for my scraper yet, so having controled scrapes pushed with my body are hard to achieve. I'm having to use my arms and keeping control is a problem. Also, my bench vise is quite high, which doesn't help.
Title: Re: Hand scraper
Post by: 4GSR on October 02, 2018, 11:53:18 AM
Got to get it down near waist high, that will help you a bunch!
Title: Re: Hand scraper
Post by: Carpenter84 on October 02, 2018, 12:14:29 PM
I have been pondering how to set that up. Another milling vise would be handy to save from having to set up a bunch of jigging.
I'll figure something out.
Title: Re: Hand scraper
Post by: 4GSR on October 02, 2018, 01:19:49 PM
Get you a welding table from HF or maybe Princess.  It's all adjustable to let you get the work surface angled for scraping.  That's all I've been using.  Need some C-clamps to use with the welding table.  Also has slots in the table that makes it easier clamping your part to the table.  Just remember, what ever method you use, do not over tighten you work piece.  You may warp it, and also take impressions with your work piece semi-loose on the table top.  And a mill vise works good on smaller pieces, too.
Title: Re: Hand scraper
Post by: Carpenter84 on October 02, 2018, 04:55:42 PM
Tried a drill press vise I have on the bench top. Too low. My big vise is a better height. But I shortened the scraper handle and smashed on a piece of plastic to grip under my arm. Much better.
I feel I'm done with this side...
Title: Re: Hand scraper
Post by: 4GSR on October 02, 2018, 05:41:26 PM
You got to change your handle.  That don't work.  Look back at the pictures of mine and Mike's for ideas.  Want something with a brad flat pad that will rest on your breast bone to push on.
Title: Re: Hand scraper
Post by: Carpenter84 on October 02, 2018, 05:48:11 PM
I know. This was a quick cobbled solution. All these things I keep having to do in order to fix this compound. I needed to just get back to scraping the straight edge so I could get back to scraping the compound. I'll make a handle/pad soon.
Title: Re: Hand scraper
Post by: Carpenter84 on October 02, 2018, 10:08:27 PM
Thhheeeerrrreeeee...

I wasted time I could have used to scrape!
Now I have to learn how to hold this thing all over again... (Properly 😁)

That old man never came through on handles, which is lame cause I wanted some file handles out of the deal too. So, I used this hard clear plastic I had bought a long time ago to make file handles myself. Never did. Lol.
Title: Re: Hand scraper
Post by: 4GSR on October 03, 2018, 07:42:01 AM
Hey, I like that! Should do you a great job! Until it splits and breaks on you. :-\

Give it a try.

Ken
Title: Re: Hand scraper
Post by: Carpenter84 on October 03, 2018, 10:59:23 AM
Until what splits? The plastic? That's why I put a tight fitting brass ferrule on the end 😁

Edit: oh, the top where the pad screws in. Yeah, I'm sure the screw will strip out first. But to be honest, I'm still finding it more comfortable at the height I'm setup to not use the pad.
However, to scrape the 45 on the straight edge I'm forced to clamp the work piece to the bench. So I may be forced to use the pad.
Title: Re: Hand scraper
Post by: Ulma Doctor on October 05, 2018, 10:52:47 PM
looking great Shawn!
the edges are always the hardest to get flat.
i always try to treat the edges very carefully
i lift up slightly when i approach the edge, or stop short altogether- leaving the edge intentionally high, then knock the edge down
Title: Re: Hand scraper
Post by: Carpenter84 on October 06, 2018, 05:48:21 AM
Thanks Mike. I had started trying to be more cautious around the edges. So i didn't wind up with that ring around the parameter.
Title: Re: Hand scraper
Post by: Uglydog on October 11, 2018, 05:17:07 PM
Nothing wrong with Sandvicks they work well.
The technique is different than with Armstrongs and the feel is different.
Sorry I can't explain it better.
You may find on other sites individuals who disparage the Sandvicks.
My scraping mentor told me to use the best scraper for the job.
They work differently due to the cutter/blade shape. A different radius (if you choose to add one) will also make a difference. Note: sometimes straight might yield the best results.
Factory handles also contribute to a different feel from what you've made.
Nothing against a shop made handle.
Not at all. More metal, more wood, steel vs aluminum handles, tubular vs flat stock, shorter vs longer.
A different handle and a different length will feel and work differently.
As will how you position yourself to the work, as well as the type of metal, and specific objectives of the task.
The above is only my learning mode opinion.... If 4gsr is mentoring you, then you are likely in great hands!!

I'm hoping to load out my Cincy TM 1D tonight at 10pm when the fork arrives.
It's been raining for 3weeks, and had light snow this morning. Am hoping we can get this done and then unloaded safely on Saturday!!

Daryl
MN
Title: Re: Hand scraper
Post by: 4GSR on October 11, 2018, 06:06:40 PM
.... If 4gsr is mentoring you, then you are likely in great hands!!

That's scary!  Lol.  I'm trying to help or corrupt Shawn.  Yep, not one scraper is a one size fit all.  I've always been a Sandvic user, it's what I pretty much learned on.  Used to have one dad made from a old power hacksaw blade.  I don't remember what happen to it after the carbide tip broke off of it.  Wish I had it today.  Oh well.  I'm too lazy to make any new ones now days.  Thanks Uglydog!  Hope your move is going good.  Ken


Title: Re: Hand scraper
Post by: Ulma Doctor on October 11, 2018, 07:57:45 PM
i have antique High Carbon Steel Scrapers, Anderson Scrapers with carbide and HSS blades, and 2 Sandvik scrapers.
i use different scrapers for different things.

i do enjoy the feel of the Anderson scraper with a carbide blade as well as my Sandvik scrapers- they both move a lot of metal, with some effort
Title: Re: Hand scraper
Post by: Carpenter84 on October 11, 2018, 08:14:50 PM
I've already discovered how I want to change my scraper and that I'd like to make two or three more of different sizes and shapes.
I ordered a 2000 grit diamond disc wheel to make a grinder.
I'm starting to understand what I need to change to do what I need done in my setups and conditions.
My vise is very nice, solid, and handy, but it's quite high. My scraper is too long for up there. And bolting a drill press vise to my bench is too low for my height and back.
But, scraping angles I clamp in a wooden handscrew clamp, so I need a medium length handle.

And I MIGHT understand which radiuses I need on the carbides.
Title: Re: Hand scraper
Post by: gtermini on October 11, 2018, 08:38:20 PM
Here's my lapping wheel. Quick and dirty. It laps the tip at about neg 5 degrees.

(https://i.imgur.com/xDateSEl.jpg?1)

A friend of mine has a Anderson with a HSS blade he cut down to about 5/8" wide from where it leaves the handle. He uses it for pin pointing on small dovetails and such. It has a really tight radius end.
Title: Re: Hand scraper
Post by: Carpenter84 on October 11, 2018, 08:55:39 PM
Nice. I think you've shown me that before. Nice and simple.
Title: Re: Hand scraper
Post by: PJB on October 12, 2018, 01:15:20 PM
Here's my lapping wheel. Quick and dirty. It laps the tip at about neg 5 degrees.

(https://i.imgur.com/xDateSEl.jpg?1)

A friend of mine has a Anderson with a HSS blade he cut down to about 5/8" wide from where it leaves the handle. He uses it for pin pointing on small dovetails and such. It has a really tight radius end.
I like it!   At work we call it Mexican engineering -and that isnt a slam - its a reference to the absolute ingenious solutions they come up with out on the factory floor when faced with a problem and little to no resources.   
Title: Re: Hand scraper
Post by: 4GSR on October 12, 2018, 01:46:35 PM
Yeah, down here it's called "Southern Engineering".  We have to be careful with our words now days. :(