Wildcat Neck Thickness-How much is too much?

[4Mesh]

Charles,
Are you saying you had a thin spot where the old neck joined? Hmmm, interesting.

I've never pushed a shoulder back before so I've never seen that. I've seen what I call, "reverse donuts" where the initial neck turn was a bit aggressive and then after fireforming there's that thin spot where I cut to far into the shoulder (and now that's neck). They never caused an issue for me so I didn't get excited about removing that.

I use a K&M neck turning tool with the carbide mandrel. I reground all my cutters and sorta liked it when I put a negative pitch on the cutter. Sorta like a drill sharpened for drilling bronze. Remove the cutting edge so it can't dig in and must be forced into the part. I used that on my brass and when I'd turn then, the inside of the neck was formed against the mandrel so the inside was absolutely smooth. No polishing needed. Used more force and made a lot more heat, but cured all neck woes.

I was never happy with the inside neck ream that I did. I got much better results either in the lathe or just neck turning (or both since after the lathe I needed to neck turn). Of course once I went to a WSM I didn't need to bother with the lathe or reamer anymore.

 

[alinwa]

I reground all my cutters and sorta liked it when I put a negative pitch on the cutter. Sorta like a drill sharpened for drilling bronze. Remove the cutting edge so it can't dig in and must be forced into the part. I used that on my brass and when I'd turn then, the inside of the neck was formed against the mandrel so the inside was absolutely smooth. No polishing needed. Used more force and made a lot more heat, but cured all neck woes.

I'm surprised it didn't iron the neck out to oversized on the mandrel.... seems like you'd get that neck floppin' like bark on a maple whistle.



al

 

[4Mesh]

Nope Al,
It actually tightens it. Well, mine does. I was only doing a slight burnish, not like I was smashing the brass flat or anything. The cutter still "cut", it just took pressure to get it to do so, like it should. I just broke the edge of the cutter after grinding the angle very precisely. I didn't just do it on the belt sander.

 

[Charles E]

I use a K&M neck turning tool with the carbide mandrel. I reground all my cutters and sorta liked it when I put a negative pitch on the cutter. . . .

I believe the K&M tools comes with a negative rake on the cutter -- did you use even more?

 

[alinwa]

Nope Al,
It actually tightens it. Well, mine does. I was only doing a slight burnish, not like I was smashing the brass flat or anything. The cutter still "cut", it just took pressure to get it to do so, like it should. I just broke the edge of the cutter after grinding the angle very precisely. I didn't just do it on the belt sander.

Ahhh, my bad. A scraped or broken cutting edge is different that what I was picturing. I was thinking in terms of a brass or bronze cutter for bar stock or drill set for boring (like cannons.)

al

 

[4Mesh]

I believe the K&M tools comes with a negative rake on the cutter -- did you use even more?

Yes, I did.

If the intent was to use a negative rake, then the manufacturing tolerances of the square broached hole and bore for the mandrel were off enough to cause "Y" axis issues with the tool (at least on mine). Much like adjusting tool height on a lathe, Mine must have been a little "lower" then cause it cut pretty aggressive. At the shoulder especially, it could dig in if I was applying too much pressure.