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Boring out brass tubing


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#1 Fred_J

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Posted 21 May 2020 - 02:13 PM

If I wanted to overbore a front axle tube on a slot car, how would I go about it? Would I use, a drill bit or a reamer, or something else?
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Fred Jespersen




#2 Dave Crevie

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Posted 21 May 2020 - 02:24 PM

Depends on how much bigger you need to go. Generally a reamer would be the choice since it will follow the bore and not walk off center like a

drill bit could. But don't try to take more than 1/64th at a time. I.E., if you are going from 3/32nds to 1/8th, use a 7/64ths ( .109 ) dia, reamer first,

then follow up with the 1/8th reamer. And use Marvel Mystery Oil to lube the reamer during the reaming operation if the tube is brass. Don't use

a hand drill to drive the reamers. Do it by hand if you have a large pin vice, or loose drill chuck.   



#3 MarkH

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Posted 21 May 2020 - 04:05 PM

If you use a drill bit, dull the cutting edge about .003 to .006". It then become more of a scraper eliminating the chatter and self screwing into the tube.

A small fine stone and a couple passes over the cutting will get you there.


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#4 Matt Sheldon

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Posted 21 May 2020 - 04:59 PM

Reamer if you have the proper sizes to progress from. Mark's advice on using a dull bit is great! When I have to open up motor brackets regardless if for an axle tube or pinion clearance, I chuck the bit up and then just turn by hand.


Matt Sheldon

#5 airhead

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Posted 22 May 2020 - 06:31 AM

McMaster - Carr  has any size reamer you would need.


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#6 Dave Crevie

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Posted 22 May 2020 - 08:54 AM

A drill bit, being two flute, will not cut a truely round hole, even with the rake broken to eliminate the cutting angle. A reamer is always the best choice.

You may be able to borrow what you need from another racer or a local machine shop. You are not the first to run into this problem. It goes way back

to when slot racing began.



#7 Eddie Fleming

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Posted 22 May 2020 - 09:52 AM

Why are you wanting to bore it out in the first place?

 

Just curious as to what problem you are trying to solve.


Eddie Fleming

#8 MSwiss

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Posted 22 May 2020 - 10:06 AM

Eddie,
I asked him the same question in the other thread by the same name.

http://slotblog.net/...ng/#entry781728

As my post also alludes to, Fred isn't real anxious to answer follow up questions, related to his original question.

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