Author Topic: M-DRO  (Read 369 times)

woodchucker

Re: M-DRO
« Reply #15 on: September 06, 2019, 01:12:21 PM »
Is there a more defined or hard set of the measured distance displayed with the mag type. Where as the glass ones tend to be a bit drifty, dicey to lock in a setting, and therefore more accurate and repeatable?

 
Pep


I haven't found them drifty, I do find the resolution more than I need. Boy it can be mind numbing seeing all those numbers  ???
Jeff
Clausing 8520   SB Model 9a - power hacksaw, Milwaukee band saw in a table.  Delta Rockwell Surface Grinder (not online yet .. being rebuilt where am I going to stick this)
For pics: https://imgur.com/user/woodchucker/posts

pep

Re: M-DRO
« Reply #16 on: September 06, 2019, 05:43:20 PM »
Is there a more defined or hard set of the measured distance displayed with the mag type. Where as the glass ones tend to be a bit drifty, dicey to lock in a setting, and therefore more accurate and repeatable?

 

I haven't found them drifty, I do find the resolution more than I need. Boy it can be mind numbing seeing all those numbers  ???

As to drifty it may be the wrong term. What was meant and as you note all the numbers. Getting 0.000000000 repeatedly as ground zero, makes the DRO feel drifty. Once set the reading is stable, getting there is the chore.

Am asking if the magnetic scale has the advantage there? If no then what is the advantage? Seems to me having a magnet in the middle of steel chips and filings is not so great.

Pep
 :-\

 I love these goofy faces, so funny

woodchucker

Re: M-DRO
« Reply #17 on: September 06, 2019, 07:20:21 PM »
I think the resolution is higher than needed.
If we were to block all the extra digits after the thousandth it would be easier.  If we can set it to read to .5 thou it would be great.
I don't think it's the scales. I think you will find both capable of millionths of an inch
Jeff
Clausing 8520   SB Model 9a - power hacksaw, Milwaukee band saw in a table.  Delta Rockwell Surface Grinder (not online yet .. being rebuilt where am I going to stick this)
For pics: https://imgur.com/user/woodchucker/posts

pep

Re: M-DRO
« Reply #18 on: September 06, 2019, 10:13:10 PM »
I think the resolution is higher than needed.
If we were to block all the extra digits after the thousandth it would be easier.  If we can set it to read to .5 thou it would be great.
I don't think it's the scales. I think you will find both capable of millionths of an inch

Winner! ^
Good idea, time to get some Black electrical tape, and mod my display.  :)

Works well on the check engine light.
Pep
« Last Edit: September 06, 2019, 10:19:24 PM by pep »

jpigg55

Re: M-DRO
« Reply #19 on: September 07, 2019, 09:01:50 AM »
I'm no expert, but from what I've read, glass scales are still better than magnetic for accuracy and repeatability, although I also read magnetic ones are getting close.
This may or mat not still be true, but like everything else, I bet a lot depends on the manufacturing process. I did read about a new process for magnetic scale encoding which is supposed to make them much better, but don't know of any scales currently using the process. I'll see if I can find the article and post the link.

For me, the big advantages of magnetic over glass are the ease of cutting to length and smaller size/profile. Big pluses for mounting on smaller hobby machines like mine. There's also that magnetic scales are supposed to be impervious to contaminants, although opinions seem to vary about this issue on glass scales. Price wise, glass scales still come out on top for equal resolution and accuracy I believe.
SB 9A, Clausing 8520, Sanford MG 612

jpigg55

Re: M-DRO
« Reply #20 on: September 07, 2019, 10:22:02 AM »
Need a little advice. I'm using the aluminum extrusions that came with the kit for the scales.
The magnetic strip has an adhesive back to glue it down, but it will cover the mounting screws making it impossible to remove the scale without peeling up the strip and possibly damaging it.
I cut the scale long enough so I could have full travel and still not cover the 2 end holes with the magnetic strip to allow removal if needed. The extrusion is pretty rigid and is flush against the table so it shouldn't flex. Once the protective cover is installed, it will be even more secure.

Question is should I or do I need to mount it using all the screws ?
The other downside is that one has to install the magnetic strip and protective cover while mounted on the machine making it somewhat awkward to do so.
SB 9A, Clausing 8520, Sanford MG 612

Terrywerm

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Re: M-DRO
« Reply #21 on: September 07, 2019, 10:50:00 AM »
I would just use the end screws and then cut the magnetic strip short enough that the screws don't get covered.
Terry

Making chips with old machines!

Bill Gruby

Re: M-DRO
« Reply #22 on: September 07, 2019, 10:53:10 AM »
 Can the mag strip be drilled? If so do it.

 "Billy G"
Don't sweat getting old, you'll still do dumb shit, just slower.

An Optimist will tell you the glass is half full, the pessimist half empty, the engineer will say the glass is twice as big as it needs to be.

jpigg55

Re: M-DRO
« Reply #23 on: September 07, 2019, 01:43:01 PM »
I would just use the end screws and then cut the magnetic strip short enough that the screws don't get covered.
That's my plan unless someone pointed out any issue with it.

Can the mag strip be drilled? If so do it.

 "Billy G"
Can't drill through the strip without ruining it.
SB 9A, Clausing 8520, Sanford MG 612

jpigg55

Re: M-DRO
« Reply #24 on: September 09, 2019, 10:08:42 PM »
I got a bit further on the install over the past couple days. Itís taking longer than I anticipated for sure.  A couple necessary changes in my plan along with a couple trips for needed supplies didnít help.
I thought the Y-axis scale was going to be an easy install, but it wasnít to be so. Everything fit tested nicely until I tried to set the protective cover in place. It was too snug between the cross-slide and the knee crank and I realized it wasnít going to fit once the cover mounting screws were added. I had to adjust my plan for this by making an additional mounting bracket so I could set the readhead further back where there is clearance.
I also realized that the covers, when drilled and mounted, will have a small overhang that Iíll need to mill off so the scales will set flush with them on.

I hope to finish the install within the next few days and can then fire it up and get to the initial set-up and testing. Depending on how that goes, I might start a new thread for that portion. Meanwhile, a couple more picsÖÖ
SB 9A, Clausing 8520, Sanford MG 612

jpigg55

Re: M-DRO
« Reply #25 on: September 16, 2019, 08:10:32 PM »
Itís been a few days since my last update and had hopes of having the install complete, but, alas, it wasnít to be so.
Everything looked good and seemed to be going to plan until I went to install the protective cover on the first scale. While the readheads are drilled and threaded for mounting in two different directions, only when mounted from the side will they fit under the shield when using the supplied hardware.
With this realization and my desire to use the shield covers (although Iím not certain they are required), I was forced to re-think, re-plan, and machine new mounting adapters in order to mount the readheads where I wanted them.
As of today, I currently have the Z-axis scale mounted, aligned, and cover on. I also finished making a new mounting bracket for the X-axis readhead. Once I have it aligned, Iíll install the magnetic tape, readhead, and cover. I still need to fashion a new mount for the Z-axis readhead at which point I will be able to install its readhead, space and align it.
After that all that will be left is tackling the Y-axis. Iím still working on how Iím going to mount that one.
Hereís a couple more pics of me aligning the Z-axis scale and installing the bracket I made for the X-axis readhead.
SB 9A, Clausing 8520, Sanford MG 612

woodchucker

Re: M-DRO
« Reply #26 on: September 16, 2019, 09:09:02 PM »
its a real pain to get the z axis set due to the non-square non-straight housing.


don't know if this helps, but here's my DRO install on the 8520..
mine were glass though.
https://www.machinistgazette.com/index.php?topic=973.15



« Last Edit: September 16, 2019, 09:14:03 PM by woodchucker »
Jeff
Clausing 8520   SB Model 9a - power hacksaw, Milwaukee band saw in a table.  Delta Rockwell Surface Grinder (not online yet .. being rebuilt where am I going to stick this)
For pics: https://imgur.com/user/woodchucker/posts

jpigg55

Re: M-DRO
« Reply #27 on: September 17, 2019, 09:52:34 AM »
its a real pain to get the z axis set due to the non-square non-straight housing.


don't know if this helps, but here's my DRO install on the 8520..
mine were glass though.
https://www.machinistgazette.com/index.php?topic=973.15
I agree setting the Z-axis is a pain. I mounted the scale to some heavy angle aluminum and used 1/4-20 hex screws through slots I machined in the angle to mount it. I used jamb nuts to hold it in place once it was aligned.
Thanks for the reminder, I did follow your install thread when you were doing it.
I didn't want to lose Y-axis travel so I opted to install my X-axis scale using the T-slot on the front of the table instead of the back. I had to cut off some of the limit block to make room though.
After looking at your Y-axis install again, I may re-visit my placement location idea. I considered mounting it in the same location you did, but was worried about interfering with the axis lock screw so I was thinking of mounting it on the other side. This has been troublesome though due to the clearance between the cross-slide and knee crank housing.
« Last Edit: September 17, 2019, 09:57:30 AM by jpigg55 »
SB 9A, Clausing 8520, Sanford MG 612

woodchucker

Re: M-DRO
« Reply #28 on: September 17, 2019, 01:42:36 PM »
if you need a better pic of the Y inst, let me know.
Jeff
Clausing 8520   SB Model 9a - power hacksaw, Milwaukee band saw in a table.  Delta Rockwell Surface Grinder (not online yet .. being rebuilt where am I going to stick this)
For pics: https://imgur.com/user/woodchucker/posts

jpigg55

Re: M-DRO
« Reply #29 on: September 17, 2019, 04:12:30 PM »
I finished up the X-axis today and got a bit further with the Z-axis install.
Hereís a couple pics of the X-axis with cover along with a short video I shot during a quick test run of the X-axis scale.

https://drive.google.com/file/d/1vX9aWTkXz-qQ13bKJt8DJluT8-JilzLr/view

Here's a couple more pictures of the X-axis with protective cover installed.
SB 9A, Clausing 8520, Sanford MG 612