# Narrow Parting Tool For Aluminum And Brass



## cathead (Feb 4, 2016)

There are times when one needs a specialized bit of toolage.  I was asked to make
a bunch of plate/grid caps for some old time radio transmitting tubes.  These caps
have very narrow grooves so had to come up with something because my 1/8 inch
HSS cutters were way too wide.  I do some lumber sawing so usually have a supply
of discarded band saw blade material around and happens to be .040 inches thick, just
perfect for my application.  The teeth on the blade were ground off 
and the blade milled off with a carbide cutter for a smooth edge.





Then I made a holder for the blade and drilled holes along the parting blade each an inch apart.




The tube pictured is an RK-38, a rare tube from long ago.  The next photo shows the tube
	

		
			
		

		
	





with the fabricated plate cap installed.  I made a bunch of these plate caps out of aluminum
for several friends who were very happy with the results.






I'm sure I will find more uses for an  .040 parting tool  for aluminum and brass.  It was a fun
project and costed basically nothing and allowed me to utilize some junk that would have
otherwise ended up at the scrappers.

I used three 1/4 x 20 stainless socket head screws to pinch the blade in the holder
and installed the clamped blade in the home made tool holder.


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## toolroom (Feb 4, 2016)

Nice job Cat... but what does the cap do? Looks like some sort of heat sink?


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## cathead (Feb 4, 2016)

Yes. it is to dissipate heat from the plate, something to help with cooling.


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## GA Gyro (Feb 4, 2016)

Just curious...

Are those old tubes still made...
Or is it one of those: When they are gone, they are gone... things.


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## silence dogood (Feb 4, 2016)

That is a radio transmitting triode tube and that round plate inside of the tube can actually get red hot when operating.  So Cat, what you made is a heat sink.  Good job.


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## cathead (Feb 5, 2016)

GA Gyro said:


> Just curious...
> 
> Are those old tubes still made...
> Or is it one of those: When they are gone, they are gone... things.



No, the RK-38 has not been made for a long long time.


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