How to make a Ring Mandrel

[bstanga]

[DIYer]

Thanks bstanga! We've added your Ring Mandrel to our Machining category,
as well as to your builder page: bstanga's Homemade Tools. Your receipt:

Ring Mandrel by bstanga

tags: taper, mandrel

[Paul Jones]

Brian,

I like the way you made the lathe dog. Great observation about the lack of chatter when using HSS vs. carbide (insert?) when machining the thin long taper. There are a lot of factors involved so hard to know the root cause but I like the true slicing action of HSS vs. plowing action of carbide inserts. On slim parts the carbide insert tends to plow in (and out) and flex the part which start a standing wave harmonic motion causing chatter. To make matters worst is the varying diameter along the length changes the parameters so you probably can't find an ideal combination of speed, feed, DOC and lubrication. The sharply hone HSS or cobalt HSS is your best bet.

Thanks for sharing,

Paul

[PJs]

Thanks Brian. Like both your Lathe Dogs. Simple, quick design but a bit hair raising fab on the metal one. As for the chatter in the middle; It could be a lot of things like Paul indicated and agree about the HSS or Cobalt. What I noticed was your tool grind didn't have much of a radius nor back rake. I have found on CRS to give a bit more radius and cock the QCTP back a bit to move to about ~3-5º into the radius tends to pull the chips a bit better and adding a shallow back rake allows them break a bit sooner.

CRS has always been tough for me on the Peanut and gone through a lot of iterations to get it the best I can. Mr. Pete had a video a while back about finish passes using a

for difficult to machine materials. It's only for final passes of a thou or two but works like a champ and uses a lot less elbow grease than lots of grits of paper to get a finish like this tool needs.

Thanks for sharing and treats for Zeke! ~PJ

**Not sure why the YT videos are now embedding rather than just being a link??

[Okapi]

Thanks for your tutorial bstanga, I just need one for my wife who need always more jewels and rings…
Have a good day.
Pierre

[Paul Jones]

PJs,

That was a new one for me regarding using a vertical shear lathe tool.

Thank you for the tip.

Paul

[bstanga]

Thanks for the kind words Paul, I did some searching and had a few comments on the video, one was use a piece of lead lightly rubbing on the work as it approached the middle, another was a final pass with a die grinder, working on fab'ing an air grinder to the tool post..

brian

[bstanga]

Thanks for your tutorial bstanga, I just need one for my wife who need always more jewels and rings…
Have a good day.
Pierre

They always need more rings...go get'er one..

[bstanga]

good tip on the shear tool, I'm gonna go grind one up.

[G.Paul]

There is no need to use a carbide tool bit. Grind your self a good quality HSS tool bit. your chatter will go away. I very seldom
use carbide