Gallery, Projects and General > How do I??

Fixing a tapered bore

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bogstandard:
Six thou is a little large for what I suggested, two thou would be pushing it.

Lapping is a slow process, with only minute amounts removed at any one time, you would have been there for hours.

John

rleete:

--- Quote from: Bernd on January 03, 2009, 01:14:57 PM ---Do you have a faceplate for your lathe?
--- End quote ---

No.  It's one of the things on the list.  I got the lathe and mill, and some cutting tools, but not much else. 

First thing is a QCTP.  I was given a whole slew of nicely ground HSS bits by an old timer at work, but they're all 3/8.  My lathe takes 5/16, so I can't use them.  BTW, I have a handful of 1/2" HSS lathe bits (also given to me) that I can't forsee using.  Can you use them?

rleete:

--- Quote from: bogstandard on January 03, 2009, 01:29:09 PM ---Six thou is a little large for what I suggested, two thou would be pushing it.
--- End quote ---

Bah.  2 thou I would have lived with, and made the piston to be a sloppy fit.  Even perfectionists like me have a point where they give up and move on. 


--- Quote from: bogstandard on January 03, 2009, 01:29:09 PM ---Lapping is a slow process, with only minute amounts removed at any one time, you would have been there for hours.
--- End quote ---

I was anyway.  Sand and check, sand and check.  I have it pretty good right now.  Probably tighter than it needs to be, and I'll have to do some final lapping, but I think it'll work.  Just stopped to check the 'puter for oil groove sizes, then I'll part off the piston.  Funny, I thought I'd have plenty of time to finish this thing, and post pictures.  As it is, I'll be lucky to have it done next weekend.

Darren:
An adjustable reamer sounds like what you need.

I have one, the type that has an adjusting end screw, but there are other types.
I use it to make bearings for turntables, each turntable may have slightly a different shaft size (nominal manufacturing sizes come into play here).
I start by drilling the bearing, then bore it to my standard undersize and then ream it to an perfect fit to match the shaft in question.

Reamers like this do a wonderful job with a superb finish. One could add a quick lap to finalise but I found this unnecessary in my application and some oil retention was of benefit.

Regards
Darren

Lot of I's... :med: sorry.....

bogstandard:
rleete,


--- Quote ---Bah.  2 thou I would have lived with
--- End quote ---

I think you got my statement wrong, I wasn't on about tolerances, but how slowly lapping removes material. Depending on the lapping agent, it can take say 1/2 hour to remove 1 thou of material.

When you said at first it was only slightly tapered, I thought maybe a max of 2 thou taper, not not a funnel shape. :D

Bogs

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