Father tries to help, ends up gouging threads on reciver....

[Captlink]

Please explane the hobbing operation of a receiver before threads are cut.

[thomae]

Please explane the hobbing operation of a receiver before threads are cut.
http://en.wikipedia.org/wiki/Hobbing

[sharpshooter]

Please explane the hobbing operation of a receiver before threads are cut.

Hobbing is not done before the threads are cut. I think you misinterpreted what I said. Thread milling is a CNC operation, and before they used CNC equipment, they used a hob mill. A hob mill works the same way, only mechanical.

[Willoughby]

wont help op this time but there is a thread on here somewhere
that says to tighten front scope mount screw 1st to see if it bottoms out on barrel threads
leaving scope mount loose
if it does -shorten screw till it don't
better accuracy & the ability to change barrels without removing mounts -
one member even posted a pic of a barrel swap jig he made
that allows leaving optic in place
a wooden jig & a modified nut wrench used with a rear entry action tool

[stangfish]

Hobbing is not done before the threads are cut. I think you misinterpreted what I said. Thread milling is a CNC operation, and before they used CNC equipment, they used a hob mill. A hob mill works the same way, only mechanical.

OK, We used to hob gears at a shop I worked in durring the early 80's. The thread hobbing on an Id I could not picture. .

[Captlink]

Hobbing is not done before the threads are cut. I think you misinterpreted what I said. Thread milling is a CNC operation, and before they used CNC equipment, they used a hob mill. A hob mill works the same way, only mechanical.

I used a gear hobber as a apprentice machinist but have never seen them used for threading.I know how bad threading can be no matter how they are formed and a truing operation is SOP in my experience.I hope the op can have the problem repaired in a cost effective way.

[Berniep]

It was a suggestion for the best way.Many times a receiver is threaded with a tap at the factory and is not true.No matter how you do it the barrel should be checked for head-space after barrel installation.Find a general machine shop if you go with a tap it's a minor job and if the guy is nice he may do it for beer money.
Setting up to "clean" ID threads with a single point bit in a lathe would be a nightmare seems to me.

[stangfish]

Not so bad. Just takes time good lighting maybe a mirror and some layout dye.

[Captlink]

Setting up to "clean" ID threads with a single point bit in a lathe would be a nightmare seems to me.

Experience makes it easy in as something as large as a receiver try resetting a bit inside .375 hole threaded 40tpi double. High magnification eye lopes help.

[sinman]

Setting up to "clean" ID threads with a single point bit in a lathe would be a nightmare seems to me.

I could do it in my sleep....well almost in my sleep. Having the right equipment helps.

[thomae]

I could do it in my sleep....well almost in my sleep. Having the right equipment helps. Stop bragging! Some of us have heavy metalworking equipment envy! :hail:

[stangfish]

If you set up your compound right it is a piece of cake like sin said. If you have a left hand threading boring bar you can turn you chuck backwards and cut from in to out and see everything.