Lapping a small bore

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rmac
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Re: Lapping a small bore

Post by rmac »

Great story! As a fellow tightwad with too much accumulated junk, I can relate. Some serious questions:
  1. Did you try to match the diameter of the tool to the bore?
  2. What grit paper did you use?
  3. How much taper was there before you started cleaning up the tool marks?
-- Russell Mac
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Bill Shields
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Re: Lapping a small bore

Post by Bill Shields »

I am a bit concerned that anyone would think about ball burnishing using the tailstock of a lathe..
.very much a nono on any lathe

My experience is that this type of process is done in an arbor or hydraulic press..never in a lathe (of any make).

The results from your 'eurika' moment are impressive
Too many things going on to bother listing them.
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Greg_Lewis
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Re: Lapping a small bore

Post by Greg_Lewis »

rmac wrote: Sun Sep 25, 2022 7:19 pm Great story! As a fellow tightwad with too much accumulated junk, I can relate. Some serious questions: 1. Did you try to match the diameter of the tool to the bore?
It is under by about the thickness of the paper plus a fudge factor of about .005.
rmac wrote: Sun Sep 25, 2022 7:19 pm 2. What grit paper did you use?
400. I should have used cloth-backed as the paper tore a bit at the outside end. I think that may be what caused the .004 taper. It and the bore were also sprayed with WD40, some of which remains on my shirt and the window behind the lathe.
rmac wrote: Sun Sep 25, 2022 7:19 pm 3. How much taper was there before you started cleaning up the tool marks? -- Russell Mac
Dunno. Didn't think to measure.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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Greg_Lewis
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Re: Lapping a small bore

Post by Greg_Lewis »

Bill Shields wrote: Sun Sep 25, 2022 7:58 pm I am a bit concerned that anyone would think about ball burnishing using the tailstock of a lathe..
.very much a nono on any lathe

My experience is that this type of process is done in an arbor or hydraulic press..never in a lathe (of any make).

The results from your 'eurika' moment are impressive

If I'd done the bearing ball thing I would have done it in the hydraulic press. The ball-bearing burnishing would have had to have been done in the lathe with the bearing on a rod in the toolpost. There is no way my wimpy lathe could do that. It complains about any cut more than about .030, and even though it's mounted on 1/2-inch plate, I can put a dti on the chuck and watch said dti move when I push on the headstock. And everything is bolted down tight. If the moon's gravity is right I can get results to .0001 but that's rare.
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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NP317
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Re: Lapping a small bore

Post by NP317 »

Another job adequately done!
:lol:
RussN
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Greg_Lewis
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Re: Lapping a small bore

Post by Greg_Lewis »

NP317 wrote: Sun Sep 25, 2022 11:39 pm Another job adequately done!
:lol:
RussN

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Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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