Neilson case lathe question

[Mr.Spradlin]

I bought a Nealson case lathe from a member here and really like it.
Just was wondering if anyone can give me some tips on how to put your brass in the collet where it is not all wobbly. Takes me several attempts to get it right.
Thanks folks
Matt

 

[mikecr]

I could never fully remove all the wobblies from that lathe. It's just poor quality in general. I did change it to a different case holder which helped a lot:
http://www.midwayusa.com/Product/352653/lee-zip-trim-case-trimmer-universal-3-jaw-chuck-case-holder

Luckily, as long as the mandrel fit is right, and the turner is handheld & allowed to self guide itself, turning results are still excellent.

 

[Mr.Spradlin]

Thanks for the info Mike.
I was looking at the set up this morning and saw that the collet would get pushed in as you pushed a case into it. Not giving you the slop I guess you would call it to seat the case flat before the collet gripped the case.
So looking around I took an old 1911 recoil spring and clipped one coil off. I places that behind the collet and put the lock ring back on.
So now the spring pushes the collet out just enough you can place a case into it. And push it in with your thumb (Thanks riverwolf for that tip) on the case mouth and tighten the ring.
Just ran 50 cases and not a single one was wobbly at all.

See it pays to keep junk around!! Never know when it might come in handy. And the wife thought I was a junk collector😀😀

 

[2tuf4u]

I also have the Nielsen case lathe---the problem appears to be in the manufacture of the case collet. I believe Don used the Forster collets which are relatively inexpensive and available in four different configurations to cover almost any size case head. Either the collet casehead steps ( bearing on the bottom of the casehead ) are uneven or it is possible the exterior collet/interior drive shaft surface are not concentric which would exert uneven pressure ( uneven clamping surface ) upon tightening against the case rim. Another explanation is that a small shoulder was formed when the collet was split during manufacture leading to nonconcentric circumferential clamping tension on the side of the casehead rim. We may be witnessing 1,2 or all 3 effects at the same time. I have been experimenting chucking a solid neck turning mandrel ----no conclusion yet. Next step would be to true the interior collet surfaces with an abrasive flat base rod with the Nielsen lathe attachment ( shaft,collet and orange knurled tightener ) chucked into the headstock and the abrasive flat end bar inserted into the tailstock or tool holder. Any thoughts?

 

[2tuf4u]

Matt- when the collet is inserted into the shaft the shoulder of the collet should be flush with the end of the shaft surface. The interior of the orange nut is angled so as to squeeze the exterior surface of the collet thus tightening against the case rim. I may go to the hardware store to try a 1 3/4- 2" spring --I fail to see why that would offset a concentricity problem. My collet stays abutted against the mainshaft when I release the tension. Any thoughts

 

[Mr.Spradlin]

So The spring pushes the collet up to the orange nut. This allows the collet to stay opened up so you can get the case seated into the collet before the collet got pushed into the shaft and close up.
My problem was as I pushed the case into the collet I also was pushing the collet into the shaft causing the collet to tighten on the case before the case was seated flat.

Here are a few picks.

 

[SmokinJoe]

Make sure you have the collet lubed lightly at the contact points inside the shaft & nut so that the collet moves freely. And make sure there are no burrs on the collet where it was saw cut. Wobbly is a minor problem with any turner using a collet, but learning a little technique to keep the case pushed against the collet right on axis will yield good results. I use Don's collet chuck arrangement on my own motor unit with great results. Have turned many thousands of cases with it over the past 20 years or so.

 

[Mr.Spradlin]

Thanks for the advise Joe.