Homemade live center

Yes it helps, thank you. I have no idea what the maximum speed of your lathe is so if you could give me a ballpark figure that would be great.
I don't imagine that you will have to touch up the points very often since they are heat treated. But if you ever need to touch up the points from normal wear and tear or a mishap, how would you go about it?
 
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My Sherline tops out at 2800 rpm.

If I need to touch up the tips, I will zero the housing in the 4 jaw with the tip in place and put a diamond flat file in a tool holder and file them accurately with the compound.
 
Thanks mikey.

The reason I ask about speeds is that I have modified the live center supplied with my lathe. The project is now at the stage of the final trueing cut on the point.

My approach for this has been to hold the MT3 taper in the lathe spindle. With the lathe spindle stationary there is a drive shaft that runs through the lathe spindle bore to drive the live center. The drill driving the center spindle has a maximum no load speed of 1350 rpm. Initial cuts have shown that the speed does not drop much when the cutting starts.

Using a very sharp HSS-Co insert and just a hint of DOC the chips amount to the finest dust I have ever produced. The first pass just hit the high spots and the second pass produced a consistently fine dust for the full length of the pass. The finish is not as shiny as I hoped but things look promising anyway.

The steel is rather tough. It is a piece of shaft from an unknown source. It seems to slip relatively easy in the 4 jaw even with the jaws are good n tight. This slipping does not marr the shaft so my impression is that it might not be the easiest steel to cut (with my equipment). Nonetheless I expect to have to touch up the point from time to time so it seems appropriate to fine tune the procedure.

There are other tools I could use to drive the center spindle. One has a variable speed control for up to 30 000 rpm. I would make that work if I thought it might be worth the effort. Making speed trials would help answer the question but I am not keen on shortening the point more than necessary.

So any guidance available from the folks here on how to improve the finish would be welcome.

For now I am focused on the final cut. Buffing/polishing could ultimately give it a mirror finish but I would like to perfect the cut first.IMG_0742.JPGIMG_0761.JPGIMG_0759.JPGIMG_0758.JPG
 
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I cannot see the tip of your cutting tool. Can you show me a pic?

One option might be to grind a shear tool. I haven't used them but they are said to take light cuts to produce fine finishes.
 
Interesting......
I could not take any decent photos with my old camera so I decided to try my new Teslong borescope that has magnification. And I see things now that my old bare eyes did not pick up before.
Photo on 2020-06-07 at 5.35 PM.jpgPhoto on 2020-06-07 at 5.35 PM #2.jpg
 

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Mike, your tool would probably work better if you try two things:
  1. Add some positive side and back rake. Currently, the tool looks to have zero rake, I think. Sorry about the crooked lines but if you regrind the tool to include side and back rake the tool will cut much cleaner.
rake.jpg
  1. Try cutting with the end cutting edge. That is, use the end edge just slightly back from the nose radius. Taking light finishing cuts with this edge will give a nice finish. Currently, you are cutting with the nose radius, which is why all those lines are showing up. You want to shave/shear the surface and using the end edge will do that for you.
 
Your post made me think of using my tangential holder.
IMG_0765.JPG
So I gave that a try. I set the tool as you mentioned and got a much better finish.
The chips looked like ultra fine steel wool.
IMG_0766.JPGIMG_0767.JPG

Thanks for your help mikey.

BTW the finish is better than it looks, it is very smooth to the touch.
It seems as good as can be expected with me at the hand wheel, probably feeding too quickly.
 
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Hawaii time sounds a bit like "territory time." with reference to the Northern Territory of Australia with Darwin as its capitol city. My late father who was based in Adelaide South Australia, had many business arrangements in the territory.

He often related a story of one such business meeting. While seated in a client's office in Darwin, the client took a phone call, hanging up, he said to my father "Excuse me, I won't be long" and left his office.

After some time contemplating his finger nails, my father got up, and went out of the office to ask the client's secretary where he was, and when will he be back. The secretary quite non plussed replied that he'd just gone down to Alice (Alice Springs) (About 1000m south) he'll be back in a couple of days.

Dad thought that it explained Territory time quite well.
 
BTW the finish is better than it looks, it is very smooth to the touch.
It seems as good as can be expected with me at the hand wheel, probably feeding too quickly.

Isn't it interesting what happens when we use the edges on our turning tools? The finish looks good; your camera is just picking up highlights. Glad you got her done!
 
We have a Swiss friend who always asks "Is that Swiss time or Filipino time" when we tell her we will be there at.....
 
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