Screw Repair

[pbiYoung]

Does anyone here have any experience and tips for repairing a screw head with TIG ?
I need to build up the damaged head and re-cut the slot, and before anyone tells me to go to the hardware store I'll add that its a slotted M2.5 x .40 screw and the slot is a custom width. I have a 0.40 gas lens, some 2% lanthanated tungsten, and some .035 MIG wire, but wondering if i need to go with a smaller 0.20 setup which I'll have to go find the parts for and then not sure my Miller syncrowave will run somethign that small.
Thanks in advance for the suggestions if anyone has done this.

 

[Alexander McGilton]

I can say that I use the Lincoln tig 300 at work for as much odd work and normal work. From making unique small wrenches to thermocouple welding. Not sure how your welder will preform with those low amperage levels. Often the true and display amps are miles off at the low rang. As the display and the system behind it are ment to almost always work in the dozens and hundreds of amps.

Anyway, try some trial and error. Get some small wood screw and try filling in the Phillips head to a pan head a few times before welding the one special one. Try using a large 1/8th electrode sharpen a sharper point than usual. The extra mass behind the point takes heat away. And the sharper point is easier to control the ark. If possible make a holder for the screw in a shaft of copper, drill and tap, then inset the screw in as a heat sink.

This is just what I have used in the past. A more experienced welder may have other advise that will extend tip life, conserve Gas and power.

 

[Harry Knutz]

Does anyone here have any experience and tips for repairing a screw head with TIG ?
I need to build up the damaged head and re-cut the slot, and before anyone tells me to go to the hardware store I'll add that its a slotted M2.5 x .40 screw and the slot is a custom width. I have a 0.40 gas lens, some 2% lanthanated tungsten, and some .035 MIG wire, but wondering if i need to go with a smaller 0.20 setup which I'll have to go find the parts for and then not sure my Miller syncrowave will run somethign that small.
Thanks in advance for the suggestions if anyone has done this.

M2 M2.5 M3 M3.5 M4 304 Stainless Steel Phillips Cross Pan Head Machine Screws | eBay

Thread Pitch: 0.4mm(M2), 0.45mm(M2.5), 0.5mm(M3), 0.6mm(M3.5), 0.7mm(M4). Material: 304 Stainless Steel.

www.ebay.com

I looked it up on this listing, They have the screw size you are looking for. I didn't look hard, But if you had to have a slotted head, I'm sure those are on Ebay too.

I am sure the ACE Hardware here in my town would also have the screw. I got a metric key for a change gear shaft there last week.

M2.5 X .40 Screw for sale | eBay

Get the best deals for M2.5 X .40 Screw at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

But to answer your question, I have repaired and renewed many screw heads for guns that had stripped slots by peening the screw slot and head completely closed and then rounding it off with real nice with a file and emery cloth and then re-cutting the slot.

 

[ChazzC]

Is there a particular reason you need to retain the specific slotted head?

 

[pbiYoung]

M2 M2.5 M3 M3.5 M4 304 Stainless Steel Phillips Cross Pan Head Machine Screws | eBay

Thread Pitch: 0.4mm(M2), 0.45mm(M2.5), 0.5mm(M3), 0.6mm(M3.5), 0.7mm(M4). Material: 304 Stainless Steel.

www.ebay.com

I looked it up on this listing, They have the screw size you are looking for. I didn't look hard, But if you had to have a slotted head, I'm sure those are on Ebay too.

I am sure the ACE Hardware here in my town would also have the screw. I got a metric key for a change gear shaft there last week.

M2.5 X .40 Screw for sale | eBay

Get the best deals for M2.5 X .40 Screw at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

But to answer your question, I have repaired and renewed many screw heads for guns that had stripped slots by peening the screw slot and head completely closed and then rounding it off with real nice with a file and emery cloth and then re-cutting the slot.

Thanks for the reply Harry , but I think you'll find if you dig a little deeper that M2.5 typically has a pitch of 0.45mm not 0.4mm. The search link title you come up with says that those screws are available (that's how the search engines work for commerce) but when you scroll down to the description you'll see that, in fact, they are selling standard thread screws. Check out any screw thread chart and I don't think you'll find a (0.4xM2.5) screw. Beyond that, I need a plain steel slotted screw, and the head is a custom height and diameter. I tried to "head" off (pun intended) the hardware store solution in the opening post, but i understand that, if a possibility, would certainly be the best choice. I don't believe in making any project more complicated than it should be. Thanks again

 

[pbiYoung]

Is there a particular reason you need to retain the specific slotted head?

Expensive shotgun

 

[pbiYoung]

I can say that I use the Lincoln tig 300 at work for as much odd work and normal work. From making unique small wrenches to thermocouple welding. Not sure how your welder will preform with those low amperage levels. Often the true and display amps are miles off at the low rang. As the display and the system behind it are ment to almost always work in the dozens and hundreds of amps.

Anyway, try some trial and error. Get some small wood screw and try filling in the Phillips head to a pan head a few times before welding the one special one. Try using a large 1/8th electrode sharpen a sharper point than usual. The extra mass behind the point takes heat away. And the sharper point is easier to control the ark. If possible make a holder for the screw in a shaft of copper, drill and tap, then inset the screw in as a heat sink.

This is just what I have used in the past. A more experienced welder may have other advise that will extend tip life, conserve Gas and power.

Thanks Alexander,
That's great advice. I planned on trying on a small piece of scrap, but hadn't thought of using a larger electrode. I can chuck it in the lathe and clean it up with a file and re-cut slot, but I just didn't want to blow it up.
Thanks

 

[Alexander McGilton]

Like child's play. I just converted some square drive 4-40 screws to pan head. 1/32 316L filler. 15 amps or less.

 

[GeneT45]

Like child's play. I just converted some square drive 4-40 screws to pan head. 1/32 316L filler. 15 amps or less.

Is that some sort of gas lens arrangement? The cup looks unlike anything I've used.

GsT

 

[Alexander McGilton]

Arc zone monster. Can't remember the model number. Fit a Number 20 torch. I can check again Monday.