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New lathe
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Author:  The Gun Pimp [ Tue Mar 24, 2020 10:54 pm ]
Post subject:  Re: New lathe

Whilst you're contemplating the purchase of a lathe you might like to obtain a copy of 'The Complete Illustrated Guide to Precision Barrel Fitting' by John Hinnant. Available from Amazon.

It's a little out of date but, when you're starting off, that's no bad thing.

Author:  Alpha1 [ Fri Mar 27, 2020 1:25 am ]
Post subject:  Re: New lathe

I think I all ready have a copy.

Author:  Alpha1 [ Wed Apr 22, 2020 10:52 pm ]
Post subject:  Re: New lathe

I all ready have a copy of The Complete Illustrated Guide to Precision Barrel Fitting' by John Hinnant.
I have been reading it to day sat in the back garden enjoying the sun shine.

Also reading Davids post and letting it sink in.
You do not need range rods to crown a barrel, nor spiders or multiple DTI's to the level you need.

You need:
A three jaw chuck.
A suitable diameter piece of black nylon or Delrin to act as a bushing for the rear of the rifle barrel.
A 4 jaw chuck.
Some soft inserts for a 4 jaw chuck.
A finger DTI
A micro boring bar (I gave you some)

Measure the internal diameter of your headstock.
Stuff a lump of Delrin in your 3 jaw and carefully machine it to size so it is going to be a snug sliding fit in your lathe headstock. Do not remove it from the lathe.

Measure the OD of the the rifle just before the largest diameter and bore the piece of Delrin in the chuck to suit.
Fit your 4 jaw.
Push the bushing in from the rear of the lathe and follow this with the barrel, get it right and the barrel will 'jam' with the muzzle sticking out of the 4 jaw by around an inch.
Insert the soft inserts, some small slips of brass of aluminium will do the job, you should have loads from me.
Lightly tighten the 4 jaw and clock the OUTSIDE of the barrel first, it is so much easier to chase a small error later on than a huge error when working with a 4 jaw unless you are lucky enough to be very experienced with clocking in. I use 4 jaws weekly if not daily and still allow a good few minutes to clock in a barrel or chamber correctly.
Now use our finger DTI on the internal bore to make the final adjustments. A 0,01mm DTI is ample (half thou ish)

Yes there will be some 'parallax' error (For want of a better word) using a bushing, at the receiver end instead of an outboard spider however it is not enough for you to worry about and you can always make spider at a later date.

The new lathe is off the menu for obvious reasons.

But shed time is keeping me sane.

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