Metal to metal glue question

SteelSlaver

SteelSlaver

Joined
Feb 17, 2007
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I bought the stuff to make some nice file guides. I am machining matching pieces of A2 that I will be attaching 1/8" Thick 1/2" wide 3" long pieces of carbide to the one face of 2 matching pieces after hardening. Each piece of A2 is 5/8 wide and 3" long and will have a 3/32 high shoulder almost 1/8" thick that the back edge of the carbide will rest against. What would be the best adhesive the use to secure the 3"x1/2" carbide backs to the A2. It will need to hold securely with some heat if used while grinding. I will have a couple thousands of A2 in front of the carbide where the guide halves clamp the the blade. This keeps the carbide itself from being clamped against the blade and marring it and putting real pressure on the carbide in this direction. I built one set sometime ago and while they work pretty well, one piece of carbide has come off twice. It isn't just the JB Weld I used on that set, that half doesn't have that bit of clearance between the clamp face and the carbide and I believe that when I clamp it jut right I put pressure on the carbide. I want these to be problem free and part of that is finding the best adhesive.

Yes, I will be selling a few, no I am NOT taking orders. This is a project I am doing in my spare time in the mornings before I wake the neighbors up hamming on my building my new house. So, I don't want to commit to anything. I am not making a lot, just enough to use up the A2 square stock I bought and end up with a couple of nice guides for myself and pay for the project.

PS anyone who thinks that good file guides are too expensive should find out how much time it takes to machine all the matching parts, plus carbide isn't cheap. I figure between the carbide, the A2 square stock, the round stock for the guides and the Allen head cap screws I'll have around $50 a unit in materials. Then there is milling time, heat treating etc.
 
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Glue ?? Many epoxies weaken at about 400 F. There are high temperature epoxies and some even that you have to cure at high temperatures Look for some of those .
Or braze the carbide on as is done in many applications.
 
Thing is I wanted to leave the A2 bodies pretty hard and the temps to braze would kill it. Wonder if silver solder will stick to carbide??????
 
Silver solder will stick to carbide, but at 1100°F and higher it will affect the temper of previously hardened steel. You probably mean silver bearing soft solder. It melts at 400°F, and would probably stick to carbide.....but would come loose at 400°F if the carbide got hot in grinding.

Braze/silver solder the carbide on. Let air cool to harden to whatever degree it does, then temper at 450°F. The A-2 will be tough and the carbide will be hard.... a win-win.
 
HA HA torch harden the A2 while I braze on the carbide, Excellent idea. But what about the 30 min soak and the temperature control?? Na. I get it. I am don't have to worry about the perfect edge just want a hard body so it doesn't ding up.

Wait a second, thin piece of silver solder or brass(I have thin brass) between the carbide and the A2 with a little clamp to hold it all in place made from some inconel I have laying around, a pouch of SS foil and into the oven she goes. Gonna try that first.

Thanks for getting me off the glue thing, This is a much better path.
 
Just a thought, I made one about 6 yrs ago from D-2. I just hardened it ....no temper. A file won't even think about scratching it. I have also used it when I was learning to get plunge lines symmetrical, it's still square. I think A-2 would be plenty hard without temper as well.
 
I am sure A2 or D2 would do fine against a file but, against a grinder I am not sure. Although every time I try to grind my plunges with a guide the edge of the belt ends up getting messed up where the corner of the steel meets the guide.
 
Why do you need the A2 hard?? I would recommend making 2 guides. One out of the A2 for hand work and one with the carbide for grinder work. That is what I have wound up with. That way you can regrind the A2 when needed to ensure the best accuracy. How do you intend to grind the carbide? SIC will work but will take forever and diamonds wheels can be expensive but doable. You need to show us your finished product.
 
Well, if you decide to try to glue them on, I might suggest Devcon 10110, steel filled epoxy. Not, its not brazing, but does not require a torch either.

Strong and tough, but machinable if necessary.

Larry
Tinkerer
 
I want the A2 hard because I want these to difficult to damage and soft A2 could get something like grinder grit embedded into the faces that clamp to the blade and mar the finish on the flats. Hardened pin will not mar or deform and help keep the alignment. I hope to never need to regrind the carbide. The 2 halves will be finish machined when bolted and pinned together. If I use a adhesive to attach them I can use a machined piece that goes across the carbide faces with a couple 1/4 bolts pulling them evenly onto the A2 bodies. If I go with the braze method I will do the same thing but I believe I will have to leave the dowel pins out and rely on some stainless bolts to hold the halves together, a inconel piece and stainless bolts to hold the carbide evenly in place while the brass is molten. Luckily I have lots of stainless bolts on my shelves.

I have 12 pieces of carbide so I can make 6 sets with carbide inserts. I have plenty od 1/4 A2 drill rod and cut up 6" of 5/8 A2 sq stock and will be making the extra A2 pieces into non carbide insert guides.

I checked into the Devcon 10110 and its temp resistance is only 250F. thanks anyway.

This stuff looks good, it actually gets stronger as it gets hotter [/url]http://www.cotronics.com/vo/cotr/pdf/952.4.pdf
 
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