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Spot welder lower tong mods

23K views 64 replies 33 participants last post by  jdsndrs 
#1 · (Edited)
Here is the way I modified my lower tong to fit inside the receiver.

I bought a 5/8" x 1' copper rod from Mcmaster-Carr (#8966K221)

Tip thread size is 8x1.25mm

The top cut is .230 deep and .735 long.
The bottom cut is .150 deep X 5.500 long.
Then cut it to length to match the upper tong.

This allows full access to the inside of the receiver, even with both rails in place.
 

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#3 ·
Thanks 7.62, that's exactly the kind of pics and info I need to get going when I am finally ready. God that reminds me I need to order that HF drill press while its still on sale.

How do you hold the rails in alignment while you weld?
So you really think the Tapco rails are junk?
 
#5 ·
Nice work(as usual)Max !! We are very lucky that you have an interest in taking pictures as well as building firearms as not everyone gets their ideas across in such clear manner.
 
#6 ·
I picked up my spot welder today. Does it make a difference how far back the tongs are into the spot welder before you tighten them down? Im trying to avoid cutting the upper tong to size. I dont own a mill so I will have to dremel the lower tong. Wish me luck.
 
#8 ·
7.62x39 said:
That's why I bought the copper rod from M-C to make the lower tong.
If you do that, you can leave the upper full length

Does it make a difference how far back the tongs are into the spot welder before you tighten them down?
 
#9 ·
The clamp that holds the tongs in, is about 2" long and secured by 4 bolts.

You could probably move the tong some, but I would think it would need to be at least halfway in, in order to secure it. Meaning you may be able to get 3/4 to 1" of adjustment out of it.
 
#10 ·
LOL...

I just posted the modification update to my 115VAC spot welder. But I posted it in the "Machine Shop" forum. Is it in the wrong forum?

I like the way you did your tong. Only thing is I don't have the capabilities to do the machining. Mine mod is the cheaper version...LOL
 
#11 ·
the mods look great. Now to bad there isn't a place to rent a spot welder from. I don't think harbor freight would let me buy one, modify, then return it after I'm done :D .
 
#13 ·
I know this is an old post but I want to thank 7.62X39 for those pictures! Just finished the mods a few minutes ago to my spot welder, and now it looks just like those pics. Although i don't have a milling machine so i used a angle grinder, worked fine. I made one test weld it came out better than perfect LOL so i stopped there for the night.

Tommorow i'll bend a flat and try that spot welder out properly. :thankyou:
 
#14 ·
I have a chance to pick up a used spot welder that does not have any tongs on it. Since I want to modify them anyway what would be the best/cheapest place/way to get a set of tongs setup this way. Can I just buy copper rod and bend it or would it be cheaper to have someone on the board make me a set? I don't have the spot welder yet so I'm just getting information at this point. If I have to buy new tongs what can I expect to pay for them?

:thankyou:
 
#15 ·
fal_shooter said:
I have a chance to pick up a used spot welder that does not have any tongs on it. Since I want to modify them anyway what would be the best/cheapest place/way to get a set of tongs setup this way. Can I just buy copper rod and bend it or would it be cheaper to have someone on the board make me a set? I don't have the spot welder yet so I'm just getting information at this point. If I have to buy new tongs what can I expect to pay for them?

:thankyou:
$34.99 for a set of replacement tongs at harbor freight. Both the regular and wide throat are the same price.
 
#18 ·
Well, it looks like I am going to need to get serious about the tong mod since I just picked up a 220 Chicago Electric spot welder on ebay for $64.00.
 
#20 ·
If anyone had one regular tong they would like to sell send me a PM. I bought a spot welder on EBay and it did not have any tongs. I bought one of the modified tongs listed here but I am still one short. I don't want to buy a full replacement set if I can get by cheaper since I only need one tong. If you replace yours with one of these and you now have one spare let me know.

Thanks
 
#21 ·
This is great infomation. I just ordered a harbor freight 230 volt spot welder on sale for $159.00
I have not received it yet. Do anyone know if the tong is the same size on this model? Also if a 3 second weld time is good on the 115 volt model do you think a 2 second weld time would be about right for the 230 volt model?
 
#24 ·
Bullet said:
Would it be a problem using a steel rod and the copper tip? AS the steel rods are available at the hardware store?
If you do this, I doubt if you get as good a weld as a copper rod. Mainly because copper and steel conduct heat differently. It is really amazing how quickly a copper rod gets hot. Even just filing on one will make it get warm. If both rods were steel, you would at least get the same heat transfer. They don't use copper just cause it is pretty looking!!
 
#26 ·
I Used the spot welder on my Sten SMG....

I have been lurking here for several weeks and took the general advice to get the Harbor Freight 110VAC spot welder while it is on sale. In short...this thing works great!

The tongs were modifed as mentioned earlier in this message series so they would fit into my 1.36" ID 4130 chromoly tubing. After practicing on several pieces of old tubing I held my breath and started to attach the legally registered Erb tube to my Sten MkV trigger box. The factory back in 1945 spot welded their tubing to the box and it sure looks "more professional" than their old way (when building the MkII and III) of bead welding it with a gas outfit.

The welds all came out perfect with no splatter, surface eruptions, etc. In fact, I used the old spot welds as a guide to place the new ones in. The tube is now solidly anchored in place and it looks totally factory in every sense of the word. The only difference is the factory spot welds were about 1/8-1/4" in diameter and my welds are a bit smaller than this...in fact, they are the size of the tips of the tongs. I actually prefer it this way so no one like ATF would think I had an old Sten and am trying to "cover it up"...these new spot welds are much more attractive, logically placed, and more uniform than the factory could ever do.

What has this got to do with AK's? A lot!

I bought a KVAR 5.45x39.5 Krinkov kit last year and now plan to build my own registered SBR Krink by using as a basis the Global Trades 1.6mm shell. This ought to be fun!

The Tom

PS: For timing, I simply counted a slow "1-2-Break". After switching off the power I left the tongs clamped on for another 2 seconds before removing them. I think the additional clamping did a lot to improve the solidity and appearance of the spot welds. Also, is is VERY worthwhile to take the additional 30-45 minutes to properly set up the welder before you actually do any work. Get the tong pressure, alignment of the tips, the rear adjusting screw, etc. all worked out ahead of time. The actual welding is then fairly anti-climactic...other than your heart racing.
 
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