Cleaning up tapped holes

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Cleaning up tapped holes

This topic has 9 replies, 8 voices, and was last updated 18 June 2012 at 16:20 by jim frohnapfel.

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9 June 2012 at 23:11 #92325
John Coates
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@johncoates48577
I'm making a tailstock die holder. The M5 tapped holes to hold the dies in place and key the holder to the shank are all done but I'm wondering how to clean them up on the inside where the bore for the shank is. The ends accessible externally can be tidied up with a countersink. But the ends inside the bore are more difficult.

What should I do? Use a needle file or wet n dry? Just seems a shame having spent so much time getting all the holes accurately located and tapped to have burrs on the inside of the internal bore.

Cheers

John

Edited By John Coates on 09/06/2012 23:12:03
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9 June 2012 at 23:11 #15580
John Coates
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@johncoates48577
inside large diameters
10 June 2012 at 01:18 #92331
David Littlewood
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@davidlittlewood51847
John,

You could use a riffler file; if you have not come across these before, they are files whose working bit is bent so they can get into internal spaces. Google them, you will find specimens ranging from a few pounds for a set – probably not brilliant, but should be good for a use or two – to £20 per file for top quality Swiss ones. They are commonly used by die makers to finish off the inside of the extremely expensive injection moulding dies, which is pretty similar to what you wish to do.

David
10 June 2012 at 08:52 #92339
Terryd
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@terryd72465
Hi John.

not much of a help now, but I would leave the bore undersize, drill and cut the threads, then finish the bore to size,

Regards

T
10 June 2012 at 09:37 #92345
colin hawes
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@colinhawes85982
Just run a reamer down the bore. Colin
10 June 2012 at 10:31 #92347
mgnbuk
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@mgnbuk
Small three square (triangular) scraper ? Like this one on Ebay 251023998259. Handy for deburring all kinds of awkward places.

Nigel B.
10 June 2012 at 12:04 #92350
blowlamp
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@blowlamp
Careful use of a Dremel type of tool with a mounted point can do this, but you need a steady hand so as not to mar other finished surfaces.

Martin.
10 June 2012 at 16:03 #92360
John Coates
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@johncoates48577
Thanks everyone

All done now. Used the small files (Swiss?) and wet n dry to get it all back to smooth with a close fit. I have loads of reamers but none the right size (1&quot to fit the shaft I'm using. This is a 1" parallel shaft about 3" long with a key with an MT3 taper on its end which fits my tailstock.

Next time I do something like this I'll plan better and use some of your suggestions. I have bought some old scrapers but not practised with them yet. I guess the curved one would be the ideal one to use.

Thanks again

John
10 June 2012 at 23:31 #92379
Jon
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@jon
Wet and dry works or similar every time, just spin the job up and feel for any imperfections as it rotating.
18 June 2012 at 16:20 #92747
jim frohnapfel
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@jimfrohnapfel22381
Hi John,

I'm a combustion turbine technician in Akron, Ohio, USA. I just read your post and wanted to share a recent experience I had cleaning tapped holes. First of all, the holes were already tapped and full of a lot of chips and debris. I did not machine the turbine assembly but was responsible for the assembly.

I chased the holes with a bottoming tap using plenty of oil. after I removed the tap I sprayed canned air not shop air. The canned air can be purchased in the electronics department of most major department stores. The advantage of using the canned air is that it comes out cold and causes the oil and chips coagulate and stick to the straw neck air dispenser. I simply wiped the chips of with a paper towel. Hope this works as well for you as it did for me.

Jim
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