Cambering and crowing with a 9" SBL

[coyotechet]

Here is how I chamber using my 9" South Bend. The Shorten head stock if from a 9" I cut it off behind the largest diameter then bored the spindle to 1.240 could not get the full 1.250 I wanted. So I just turn the flat to 1.230. I use to do all my chambering and crowning using the steady rest but could never get the run out to anything much under .0015. Now I can get the total run out to well under .0005 (.00025 and less)using a Interapid 312B-15 indicator with a 2 3/4 inch needle point well up into the barrel. Building this set up took me the best part of two years to build and get running true well under .0005. Lots of work but was fun and turned out btter then I was hoping for. I use a dead center and four jaw chuck to indicate the muzzel end to under .0005 using a Mitutoyo 513-402 indicator. All my chambers now have a run out of less the .0005
and are within .0005 of cutting reamer. Needless to say I am happing with the out come.

[randyc]

Man, that's a nice setup and a very clever idea! Out of curiosity, how much time is required for the setup (not including the actual chambering operation)? Also, it might be my eyes or the size of the photo but it's not quite clear how you're holding the reamer. It would be interesting to hear about it.

Thanks for the pretty pictures,
Randy

[coyotechet]

Randyc
It does take a little time setting up I indicate both end four to six time because the close fitting of the shorten head stock. The littlest out of linement will cause it to bind a little. So I adjust back off adjust back off both ends until it is a total bind free setup under .0005 TIR at both ends.
The No.2 morse taper 3/8s mill holder I bored out to .4375 (7/16) to the shank size of the floating reamer holder I made and surfaced hardened it with Kasenit hardening compound No.1. Thanks for your nice reply.
Chet

[randyc]

Chet:

Thank YOU for the explanation and additional photographs. I (usually) manage to cobble up some kind of rig that gets a job done but NEVER does it look as nice as your chambering setup. It's been my experience that a setup that looks as good and as sturdy as that one goes a long way toward operator confidence, which then produces good results !

Looking forward to seeing more of your work,
Randy

PS: That South Bend looks NEW, you sure take good care of your tools !