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doubleD
December 18, 2005, 03:10 PM
Need some advise --- I am resurecting an old project, sporterizing an Arisaka model 99. I need to change the bolt handle for scope mounting. I have not welded a bolt handle before. I have the jig, and have another bolt on the way for a practice run.

My questions -- should I use an aluminum insert for a heat sink, in addition to the heat stop paste? There does not appear to be a theaded heat sink available as there is for the Mauser. Is the heat stop paste only enough?

Brownells sell a nickel steel welding rod, does this make a difference in the ease and end result in the welding of the bolt handle? What other welding rod is recommended for this type of product?

Any advise and tips gladly accepted.

mete
December 18, 2005, 06:09 PM
I've just wrapped the bolt in a wet rag .That nickel rod is a good choice. Make sure you get a good weld , full penetration , no porosity.

cntryboy1289
December 18, 2005, 09:38 PM
I like the rods you referred to, you will like them yourself. As far as a heat sink goes, if you have access to a lathe, you could make your on heatsink. If you don't get a piece that fills the bolt and slide it in your bolt. I use heat shield paste and wrap wet rags around the lugs myself. You should be fine with it.

James K
December 19, 2005, 12:24 PM
A piece of copper ground rod makes a good inside heat sink and you can turn sections to fit any bolt. Leave about a foot sticking out as a radiator. It is hard to get the Arisaka bolt down low enough because of the rear receiver bridge, but it can be done.

Jim

doubleD
December 20, 2005, 06:39 PM
Thanks, this was the advise I needed. Will post how it turns out, or any problems which arise. Have not received the "practice" bolt as yet coming from Numeric.

Toney
December 20, 2005, 09:17 PM
Here a weldless one i just did

doubleD
December 21, 2005, 09:32 AM
Toney,
Thanks for the pic. I am not familiar with a "weldless" conversion for the bolt handle except for the Mosin. Is this something you came up with or are the bolt handles avail.? If so "who, what, where?" The pict looked like it had an "antler knob" or is this just my old eyes? Is there any concern with strength with this type of set-up?
again thanks :)

Toney
December 21, 2005, 10:33 AM
Hey D

I found this on a web page it works pretty good. I used one of my puller bolts a grade 5, 1/4" and a peice of antler tip. The page was the steve warner home page i found the link on the c&r firearm forum a long time ago but can't find it agian.

Drill your hole in for the handle so half of the new handle fits inside a notch filed in the reciver

You can always weld it latter

Toney
December 21, 2005, 10:43 AM
Another pic

Unclenick
December 21, 2005, 10:54 AM
The old method of blocking heat was to bury the part of the bolt you need to protect in sharp sand (washed white sandbox stuff) and add water to level with the top of the sand. As the water evaporates it carries off the excess heat and replacement water flows in from surrounding sand. Heat stop paste works on the same principle, but the phase change material is lanolin rather than water. It may be a bit easier than cleaning the sand out later, but you have to watch that you don't let it dry completely during the weld. Once dry, it isn't blocking heat anymore.

Next to silver, copper is the best heat conductor there is. About twice as good as aluminum and about 12 times the conductivity of carbon steel, so it makes a good welding chill. You can make a piece to go into the bolt and or to clamp on outside it between the weld site and the bolt lugs. The longer/bigger you make the chill, the more heat capacity it will have and the more area it will have for losing drawn off heat to the air. You could even make a long rod with one end in a bucket of ice water for better heat removal.

Good luck,

Nick

doubleD
December 23, 2005, 11:17 AM
Toney, thanks for the further info and pic, it helped my understanding.

Unclenick, great info, especially on the heat stop paste, I was unaware that it lost its ability when it dryed. Also on the heat sink, I would have assumed and used alum thinking it would pull the heat the best.

Merry Christmas
DD