Author Topic: Is this a valid test?  (Read 5030 times)

Bamban

Is this a valid test?
« on: August 03, 2018, 08:11:13 PM »
With the MT3 test bar dialed in near the chuck, I introduced the TS quill to the taper and watched the indicator for any movement as I cranked the quill in and out. Is this a valid test to verify the TS to HS alignment in the vertical plane?

I have the barbell and an aluminum bar stock to turn and verify, and adjust the alignment between the two. I am just looking for another way besides chunking aluminum swarf all over.

Watch "SBL 13 Testing HS to TS Alignment" on YouTube
https://youtu.be/g-6s-Q-3jOw


Thank you.


Regards,
Nez
« Last Edit: August 03, 2018, 08:52:27 PM by Bamban »
USAF 1972-1978
Distinguished Rifleman Badge 1234
P100
High Master XC, LR

4GSR

Re: Is this a valid test?
« Reply #1 on: August 03, 2018, 08:33:28 PM »
Never see it done that way.  Looks like your tailstock is a little low, which is not bad for a 70 year old SBL.

There's so many ways of checking alignment of the tailstock to the headstock.  The main thing is making sure the alignment of the headstock to the bed is correct before checking the tailstock.  Kind of hard to check when you don't have your carriage on you lathe, thanks to me!

Ken

edit: Now, one thing you can do is use the tailstock to check the headstock alignment. Once that is done, check the tailstock alignment.
« Last Edit: August 03, 2018, 08:37:21 PM by 4GSR »
Ken

Bamban

Re: Is this a valid test?
« Reply #2 on: August 03, 2018, 08:48:02 PM »
Ken,

The last time I checked the HS alignment it was cutting fairly straight.

I needed to thread a long barrel extension for AR15s, the new tenon I am using is 20 TPI instead of the original 16. For the 13/16 x 20 I was going to power tap a stock with .750 ID, which should be close enough for the 13/16 x 20 thread I would think. The reason I wanted to check the TS to HS alignment.

Is the TS lower or higher than the HS, the dial indicator swings CW when I crank the quill into the taper? Assuming the MT3 test bar is straight.

Thank you.

Regards,
Nez
« Last Edit: August 03, 2018, 08:50:23 PM by Bamban »
USAF 1972-1978
Distinguished Rifleman Badge 1234
P100
High Master XC, LR

4GSR

Re: Is this a valid test?
« Reply #3 on: August 03, 2018, 08:53:37 PM »
Oh, you know what, you are correct, the tailstock is slightly high by .0025".
I was wrong.  Is .0025" going to kill you on alignment?
Ken

Bamban

Re: Is this a valid test?
« Reply #4 on: August 03, 2018, 09:08:26 PM »
Oh, you know what, you are correct, the tailstock is slightly high by .0025".
I was wrong.  Is .0025" going to kill you on alignment?

Most likely not going to hurt what I need to do.

The barrels come in at 1.020, to be finished to 1.00x from the back of the barrel extension (BE), then it steps to .750 to the muzzle. We use a clamp on gas block. After the chamber is done I will turn the remaining stick out to about 1.007, not critical, I use this to dial in the barrel when I flip it to turn the rest. That short section should be concentric to the bore. Normally with the set thru chuck (in the case of the sample picture, BE was chucked up in the combination chuck) I just clamp on the BE, which is about an inch long, and as mentioned I dial the barrel on that turned section ahead of the BE.

My thoughts it may not be a good idea to just use the front section of the jaws to clamp on the material, thus the reason I wanted to tap that stock with .750 ID so I can have, say a 6 inch extension, long enough for the rest the chuck jaws grabbing on the material.

« Last Edit: August 03, 2018, 09:34:18 PM by Bamban »
USAF 1972-1978
Distinguished Rifleman Badge 1234
P100
High Master XC, LR

4GSR

Re: Is this a valid test?
« Reply #5 on: August 03, 2018, 09:38:26 PM »
I got to get your carriage finished and back to you! :-[
Ken

Bamban

Re: Is this a valid test?
« Reply #6 on: August 03, 2018, 09:43:15 PM »
I got to get your carriage finished and back to you! :-[

Ken,

As I mentioned before, the project is a filler job, I have the 1236 to turn down barrels and the Baby Jet 1024 to chamber with.

We both have some medical things to worry about, the project is low priority.

Here is a video on how I turn the final dimension done on the 1236.

Watch "1236 Finishing Cut, BE Chucked Up" on YouTube
https://youtu.be/3UhcupwFIJI
« Last Edit: August 03, 2018, 09:59:34 PM by Bamban »
USAF 1972-1978
Distinguished Rifleman Badge 1234
P100
High Master XC, LR

4GSR

Re: Is this a valid test?
« Reply #7 on: August 03, 2018, 10:00:12 PM »
I got to get me a few DCGT inserts.  I have a holder for my 9" SBL, just need to get a larger size for my 14" lathe.

Yeah, our knee issues are a pain in the a&& to deal with.  Wonder if a man can over dose on Acetaminophens? (Tylenol) ;D ;D :(
Ken

Bamban

Re: Is this a valid test?
« Reply #8 on: August 03, 2018, 10:05:03 PM »
Email me your address again I will send you a box of DCGT 32.51 and 32.52. I have been buying  a box or 2 every now and then. They are Chinese, but pretty good, I use them on SS 416R.
« Last Edit: August 04, 2018, 07:00:21 AM by Bamban »
USAF 1972-1978
Distinguished Rifleman Badge 1234
P100
High Master XC, LR