[How do I?] Deal with this?

[Ulma Doctor]

that's why i don't own any new machine tools in the shop (unless they are old), if i knew what it was like to use a brand new machine tool- i'd probably dump half my junk!

 

[scwhite]

Do a search for "follower rest". Your center section is just pushing away from the tool. How you've done it without a lot of chatter is what I want to know.

I agree with Holescreek
Get you a follow rest .

 

[Holescreek]

Funny how my eyes played tricks on me tonight. I looked at your mic readings and completely ignored the zero preceding the numbers after the decimal point. I'm glad I only machine in the mornings! .003" is not bad at all for the length and support given.

 

[kd4gij]

Another vote for a follow rest.

 

[Bamban]

Thank you all for the responses.

Since I do not have a FR for this lathe, I will now have to finalize the design on a pneumatic fellow rest. In the meantime I will follow up on UlmaDoctor's suggestions.

 

[cathead]

Over the months I've been doing 20 inch AR barrels, I had the TS dialed in to the HS, but I never measured the center part of the barrel until recently. Today just to see if what I saw before was repeatable, so I started another barrel for my own consumption for the upcoming match at the end of the month. It looks like the what I saw before is repeatable.

Could this fat in the middle be corrected by machine scrapping? Others suggested to just emery cloth the situation. Well, that is another art on its own. I tried it I could not get the material even the length of it.

The fat in the middle is not a critical dimension, but I would rather get it fixed if fixable. Again, this 1236 is an old Taiwanese lathe, it may very well be something I just need to live it.

The 6J is a set thru that I dial the barrel on the register that I turn during chambering. The barrel is screwed on to a long barrel extension and it is held in place by a copper ring to allow the barrel to pivot.

Thoughts?View attachment 231902 View attachment 231903 View attachment 231904 View attachment 231905

Your typo:


I have to laugh. You mention correcting the fat with machine scrapping. I'm sure you meant machine scraping.

What a difference an extra p makes!


You can laugh too as this was not meant personally.

 

[seasicksteve]

If you dont have a follow you could probably fab something like this without too much trouble. Should work well on ar type barrels.
http://www.frets.com/HomeShopTech/Tooling/MiniFollower/minifollower.html

 

[Bamban]

Another vote for a follow rest.

If you dont have a follow you could probably fab something like this without too much trouble. Should work well on ar type barrels.
http://www.frets.com/HomeShopTech/Tooling/MiniFollower/minifollower.html

I just happen to have an Aloris double tool holder, been wondering what would be the best utilization for it.

Thanks.

 

[owl]

Thank you.

The good thing about AR15 barrels the contours are all straight and just steps down to another straight dimensions. The shoulders are just chamfered at 45 degrees and not more than 0.020 just to break the edge.

OK, I give up. What do you mean by "put a bit of swamp to it"

swamping is thinning in the middle, then flaring back out. it was common on early flintlocks.

 

[Silverbullet]

Some of the deflection could be in the tightening of the tailstock . Its pinched between two points , it happens often , follow rest should eliminate most if not all. The reason they were invented.