Help boring a hole

Galileu

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Mar 24, 2011
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Hi,

I didn't anticipate any particular problems for boring the cylindre of my first steam engine, but things got a bit complicated. The plans call for a 12mm ID bore and my chuck will only take 10mm drill bits, so I thought I would drill at 10mm and then use a boring bar to open the other 2mm.
First problem was that my 10x10mm shank boring bars wouldn't go into the 10mm hole. I ordered a 6x6mm shank, brazed carbide boring bar, from RDG tools, but it just won't cut anything at all; it will rather flex than cut. I tried to grind my own boring bar from a file but that didn't work either, possibly from lack of grinding experience.
I am sure I will eventually solve the problem but today I got I couldn't find a solution with the means I have at home.

Best regards,
Jose
 
krv3000 link=topic=2362.msg15806#msg15806 date=1307209137 said:
hi well get a 12 mm drill and mashen the shank dawn to 10mm to fit your chuck but relay you shod drill out say 11.8 mm then Rem out to 12mm

Thanks! In any case I shall have to wait for monday, since I won't find hardware shops open during the weekend; I was hoping to get some work done today and tomorrow but there's really no rush!

Best regards,
Jose
 
Last edited by a moderator:
Tony Wells link=topic=2362.msg15810#msg15810 date=1307211326 said:
Jose,
how deep is this bore?

It's 30 mm through; the cylindre gets a cap afterwards.

Jose
 
Last edited by a moderator:
Thank you all for the suggestions, I'll just add that the 12mm ID is not critical, since I can machine the piston to the final diameter of the cylindre bore; I'll probably get a 12mm drill bit, reduce the shank to suit the chuck and drill the cylindre with it. Afterwards I will polish it inside with emery and polishing compound; whatever final diameter I get is what I will turn the piston to fit.

Jose
 
Hi dalee,

I'm sure that's what's happening with my boring bar; the thought came to me in bed and I haven't had a chance to look at it yet, but I'm sure you're right. Thanks!

Jose
 
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