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Floating Reamer holder verse rigid.

I finally have something worthwhile to add. I have used three different floating reamer holders. A Manson (one time), the eBay one (many times), and the JGS (use the most and currently use at work and at home). The only oversize chamber I have cut was with the Manson. It hung up on me--probably just needs polished a little.

We got our new Kingston HJ-1100 set up in the shop this past week. Our plan is to use it as more of a production type lathe, and then have me to the weird stuff on the PM 1440GT.

Our new lathe operator is truly a new lathe operator. Bruce Thom has come by the shop twice now to set up the Kingston. I pressed him pretty hard today about whether we should get a JGS floater for this lathe, since the operator is brand new.

Bruce said no. He is so confident in his setup that he says rigid is the way to go. He says after he sets it up there won't be any oversize chambers. Because it's Bruce, we are going to do it his way on the Kingston.

About a month ago he had us to his house to show us his way on a 338 Lapua IMP with his rigid reamer holder. The next day I dialed that barrel in the 1440GT, and the chamber was perfect.

Anyway, Bruce has checked everything possible on our new Kingston. He checked things I didn't know to check. I suspect the chambers will come out okay out of this machine.

As part of this Kingston acquisition we also had to move the 1440GT. As I described in my leveling thread, Bruce showed me a much better way to level lathes. I got the 1440GT to within .0001" of twist.

After leveling, I checked headstock alignment by cutting a test bar that protruded 4" from the chuck. It was .001" larger at the chuck that it was toward the tailstock.

I read the instructions in the manual on how to adjust the headstock, the called PM to make sure I understood what I was doing. The PM Tech said to not try to adjust the headstock. He said to put a shim between the stand and the lathe on the tailstock side away from me.

I asked how much shim and he said it would be such a small shim that it would be very hard to do. He then said .001" over 4" was fine.

I asked Bruce about this and he thought that was fine for the 1440GT because it was such a small and lightweight lathe. He said he thought it would keep moving on me and that I would wind up chasing it and never really get it better.

Conversely, he said the 3500lb Kingston was capable of holding a tighter tolerance and he would make sure it was set up that way.

I suppose a quarter thousandth over a typical .75 to 1" long tenon isn't a big deal. However, I do now better see the value in a heavy lathe. I wish I could find a 2000 lb stand for both the 1440GT and my 1340GT at home. It still wouldn't be quality as rigid as the Kingston, but I think it would help.

Not that any of this will make any of my rifles shoot better...........
 
INTJ said:
After leveling, I checked headstock alignment by cutting a test bar that protruded 4" from the chuck. It was .001" larger at the chuck that it was toward the tailstock.

I read the instructions in the manual on how to adjust the headstock, the called PM to make sure I understood what I was doing. The PM Tech said to not try to adjust the headstock. He said to put a shim between the stand and the lathe on the tailstock side away from me.

I asked how much shim and he said it would be such a small shim that it would be very hard to do. He then said .001" over 4" was fine.

I asked Bruce about this and he thought that was fine for the 1440GT because it was such a small and lightweight lathe. He said he thought it would keep moving on me and that I would wind up chasing it and never really get it better.

Conversely, he said the 3500lb Kingston was capable of holding a tighter tolerance and he would make sure it was set up that way.

I suppose a quarter thousandth over a typical .75 to 1" long tenon isn't a big deal. However, I do now better see the value in a heavy lathe. I wish I could find a 2000 lb stand for both the 1440GT and my 1340GT at home. It still wouldn't be quality as rigid as the Kingston, but I think it would help.

Not that any of this will make any of my rifles shoot better...........
Click to expand...

The 90s vintage Taiwanese built 1236 I acquired in 94 sits on twin towers base system. I connected both towers with grown men's Leggo - unistruts, but system is still flimsy.

20220111_152113.jpg

Fast forward to Jan 2022, I embarked on replacing the base with this. 80x28 and it stands 24 inches off the floor. Construction is from 4 inch U channels. No idea on actual weight, picked it up from an Austin CL listing. A couple of guys had a hard time picking it up, had to use an engine hoist. Just so happen the top braces lined up nicely to the bed feet mounting holes.

20220111_184818.jpg

After leveling the base, to align the lathe had to use shims between base and lathe mounting pads. Aligning the headstock gave me the opportunity to replace the sockets mounting bolts with 12 point ARPs. Much easier to turn and torque down.

20220212_140042.jpg

Did not bother to paint the lathe I was more interested in getting it to run straight. For a fairly old lathe it is not bad. Spindle still runs true.

Verified performance after headstock, and bed swimming.

20220221_004320.jpg
20220221_004337.jpg
 
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Aligned the tailstock at the distance where I turn the front section of AR barrels. Had to shim it to align.

20220301_223048.jpg20220301_223108.jpg20220301_223407.jpg20220301_223434.jpg

With the motor relocated to the base, was originally bolted to the side of the lathe bed, and coupled with heavy rigid base I can run the spindle at 2K plus with no vibration. There is a harmonic hum forgot what rpm now.

Sadly the carriage drive DRO scale died less than a year, had to reinstall the TravADial with a modified mount to work in conjunction with cross slide DRO

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How often is it necessary to check the headstock and tailstock for parallel axial alignment when using a ridged holder?

All it would take is a chip.
 
Lathes can settle and move. If the concrete is new, if another big piece of equipment gets set close by, etc. Bruce checks his all the time. I guess that is just the price of going rigid.
 
Dusty Stevens said:
I actually like holding the handle so i can feel rotational forces, let it slip if i need to plus let it spin as i stop the lathe and not withdraw it under power. Youd be surprised at how you get to know a reamer and how it cuts and when it needs sharpened
Click to expand...
Dang Skippy! You can sure feel the "grain" in the steel as it is cutting, and a Major thing, how well your cutting fluid is reducing friction in the cut.
 
I have the PTG bar... I use it to center up my set-true. I wasn't sure if the centers are true on it or not.
 
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