Thread: Floating reamer holder

I designed and made this reamer holder a while back. It is a different approach to the conventional floating reamer holders in that it rigidly holds the reamer but is adjustable in all directions. The reamer is dialed in perfectly concentric with the lathe centerline before cutting, both on the pilot shank and the rear reamer shank. There is very little need for pilot bushings with this holder.

It can be adjusted in 4 directions from the rear adjuster set and also for angle in 4 directions from the front adjuster set. There is a spherical face between the two that allows this angular change but still have high rigidity when clamped. Chambers cut with this measure true to the reamer and have zero runout.

I should say that my lathe tailstock has had a fair bit of fettling to get it sitting perfectly true with the centerline. If your tailstock has angular misalignment, it will introduce side cutting force when advancing the tailstock quill.

I pre-bore the chamber with the end of the bore being the same angle as the cartridge shoulder.

Originally Posted by SixtyTen

I designed and made this reamer holder a while back. It is a different approach to the conventional floating reamer holders in that it rigidly holds the reamer but is adjustable in all directions. The reamer is dialed in perfectly concentric with the lathe centerline before cutting, both on the pilot shank and the rear reamer shank. There is very little need for pilot bushings with this holder.

It can be adjusted in 4 directions from the rear adjuster set and also for angle in 4 directions from the front adjuster set. There is a spherical face between the two that allows this angular change but still have high rigidity when clamped. Chambers cut with this measure true to the reamer and have zero runout.

I should say that my lathe tailstock has had a fair bit of fettling to get it sitting perfectly true with the centerline. If your tailstock has angular misalignment, it will introduce side cutting force when advancing the tailstock quill.

I pre-bore the chamber with the end of the bore being the same angle as the cartridge shoulder.

Attachment 271909

Attachment 271910

Is this similar in detail to the true bore alignment system from straightshot gunsmithing?

It would be nice to see the parts and know what model lathe you have it mounted on in the photos.

Originally Posted by 19Badger

Is this similar in detail to the true bore alignment system from straightshot gunsmithing?

It would be nice to see the parts and know what model lathe you have it mounted on in the photos.

Yes, it was based on that idea and miniaturised to suit. It mounts via an MT3 shank I machined and uses an ER20 collet for tool holding.

The lathe is a Jessey 1440, quite a nice Taiwanese lathe.

Originally Posted by SixtyTen

Yes, it was based on that idea and miniaturised to suit. It mounts via an MT3 shank I machined and uses an ER20 collet for tool holding.

The lathe is a Jessey 1440, quite a nice Taiwanese lathe.

Thanks, have you got any dismantled pics?

The Jessey lathe are a nice lathe, has it got the 2" spindle bore and D1-5?