I need a heatsink was wondering which would be better, aluminium , or brass, and how far should it extend past the threads and protrude on the outside , or just use a 1/2 " bolt. Thanks

I use aluminum mainly and it extends far enough out to where I can clamp the heat sink in my bench vise or use it as a handle.

is there any reason to turn it down so it extends past the threads into the bolt cavity? thanks for the reply

quote:

Originally posted by Mike Ray:
is there any reason to turn it down so it extends past the threads into the bolt cavity? thanks for the reply

The heat sink needs to extend in both directions from the heat point in order to draw away the most heat.

Generally speaking, the more material that extends away from the heat point the better. (within reason of course)

The one I have has about a 3/4" hex head section about 1" long to the rear to aide in screwing it in & out as well as for added material to absorb heat. It also extends most of the way to the front of the bolt body @ a diameter that is small enough asto not transfer any heat into the forward portion of the bolt body.

BTW: For maximum heat absorbsion, nothing beats copper. It is used in safe linings for that very reason. I would think aluminum would be a close 2nd. Probably as good or better than brass.

thanks guys.

I asked a man who works on racing car engines about this a long time ago.

He said aluminium as it "gets rid" of the heat far quicker than brass.

How about plumbing it, with a through-hole and fittings of course, to hook up a cheap aquarium pump with water flow?

quote:

Originally posted by 1 Shot Hunter:
How about plumbing it, with a through-hole and fittings of course, to hook up a cheap aquarium pump with water flow?

That could be downright dangerous. Steam expands @ a ratio of 1600:1 to the volume of water @ atmospheric pressure.

I have welded bolt handles on with an oxy/acetylene torch using a standard aluminium heat sink. That is far from the ideal method. Non the less, buy only welding in stages allowing some time to cool in between, I am able to use a standard aluminum heat sink/heat absorbing paste to keep from drawing out the proper temper of the cocking cam surface & rear safety lug.

W/a more appropriate TIG torch, the aluminum heat sink will be more than sufficient.

Not dangerous at all! Ever see a pressure-sealed aquarium? I haven't either...

quote:

Originally posted by 1 Shot Hunter:
Not dangerous at all! Ever see a pressure-sealed aquarium? I haven't either...

But have you ever welded on your aquarium?
Regards, Joe

TIG weld it using a brass or copper heat sink & 20scf argon purge.

Using aluminum as a heat sink while TIG welding- the aluminum will migrate/contaminate.

quote:

Originally posted by J.D.Steele:
But have you ever welded on your aquarium?
Regards, Joe

The plumbing idea will work fine if you have enough pressure and don't attempt to recirculate the water. Additionally you might want to draw the water instead of pushing it through due to the small size application.

I know the plumbing will work because I have experienced it on a larger scale. Submerged-arc welding of oilfield tool joints.

I suggest drawing or sucking the coolant through as this is much more effective means of removing heat in injection molds with complex geometry and long thin metal structures-even if you are using turbo baffles.

I suggest using steel with an external protrusion of at least 1" and 2" is sometimes better.

This tool is much more effective as a holding mandrel than it will ever be as a heat sink, regardless of marketing hype. Drill & tap for a large-dia brass screw to thread into the side of the mandrel in the bolt's cocking cam slot, to lock the bolt body onto the mandrel when working on it.

If you're concerned about the heat-treat of the Mauser bolt body surfaces, I suggest you study the (very simple) technique of re-heat-treating with a torch.

All of this AIN'T rocket science, it's basically very simple blacksmith work along with some common sense.
Regards, Joe

I use a threaded aluminum sink with a hole through the middle, a bicycle inner tube wired over the vent holes and lugs hook up a water hose and cool while TIG welding, no need to reheat treat

There ya go! A step easier than a pump!