[TheForge] Fw: cutting off copper ferrules?

[David E. Smucker]

Well said Charles.

Dave

--------------------------------------------------
From: <xlch58 at swbell.net>
Sent: Wednesday, July 29, 2009 2:02 PM
To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
Subject: Re: [TheForge] cutting off copper ferrules?

> Bruce Freeman wrote:
>> Lots of good ideas.  Thanks.
>>
>> I'd heard copper worked differently on the lathe than other metals,
>> but I didn't know what to do about it.
>>
>> I tried a sharp parting tool and had trouble.  Strange that a slightly
>> dulled one should work.  I guess it's a question of grabbing the
>> copper.  I also tried a hacksaw while the tube was spinning in the
>> lathe, and did not have good results.  I probably should get an
>> assortment of good hacksaw blades, but this approach wasn't promising.
>>
>> I think I'll try them in this order:
>>
>> 1) Tubing cutter with a 1/2" rod inside the copper tube.  The burrs on
>> the end are the killer.  I could tolerate it on one end, but not on
>> the other where it has to slip on.  Clearance is too tight.  If the
>> burr were tiny enough I'd just clean it up with the file, but I was
>> getting substantial constriction of the tubing.   I have a drift for
>> swelling the end of soft copper pipe to obviate using a union, but I
>> doubt it has a purely 1/2" diameter section.  I'll check.  If I don't
>> have 1/2" rod or dowel, I can easily get one.  I like the idea of
>> doing this on the lathe.  I could probably use the roller assembly
>> from a tubing cutter as a lathe tool...
>>
>>   
> If you don't want to try a negative rake, then I would suggest the 
> following:
> 
> 1. mount a 3/4 inch diameter 3 inch long W1 carbon steel rod in the 
> lathe.  2. turn a one inch length of it down to a half inch, or the 
> maximum that your tailstock chuck can take.
> 3. Reverse it in the lathe, mounting and centering the half inch 
> diameter spigot in the jaws
> 4. Set your compound rest to a very shallow angle of of 3-5 degrees and 
> start cutting the bar down so that the section next to the chuck is a 
> tad over the inside diameter that you want. Use a high speed, very fine 
> feed and light cuts to get a good finish.
> 5. Assuming that you have a clean finish polish it using strips of one 
> inch wide abrasive paper. 6. If you have a knurling tool, knurl the very 
> tip for an half inch or so.
> 7.  Harden the tool using standard blacksmithing procedure.  Leave the 
> shaft end that will go in the chuck as soft as possible.
> 
> Now,
> 1. Mount your new tool in the tailstock chuck.
> 2. Mount the tubing in the lathe as you have been
> 3. Put the lathe in the lowest gear ( for your atlas this would be the 
> chance to use the backgear)
> 4. Put a normal plumbers tubing cutter on it. Or you can use a cuttoff 
> tool with a negative rake.
> 5. Turn the lathe on low.
> 6. After the tubing section comes off, then advance the tailstock tool 
> into the pipe to ream and swage the end
> 7. Repeat.
> 
> This will result in an assembley line procedure for making tube sections 
> with two very clean ends, and one end with the diameter properly 
> sized.   There is a science to cutting steel by the way.  What many 
> people don't realize is the cutting surfaces of the cutting tool do NOT 
> actually cut the metal, the material pushed ahead of it does.   Steel 
> behaves different from non ferrous metals.  Positive rake for steel,  
> negative rake for brass, aluminium etc.
> 
> Charles
> 
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