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Posted

I am new to blacksmithing, but I try to learn everything that I can. I looked all over to try to find a formula to determine the rivet head size and height of a given diameter of parent stock, but I couldn't find anything but tables showing some of the dimensions. Using that data I came up with something I would like to share with everyone else:
Using Y = Diameter of parent stock X = Diameter of the rivet head and H = Height of rivet head
7Y = 4X and X - Y = H
Using this I can determine the dimensions of my rivet with ease. Forgive me if I overlooked this topic elsewhere. Any input/opinions would be greatly appreciated because like I said I'm new to this and value other peoples experience and knowledge. Thank you in advance.

Posted

Ahh there are all sorts of rivet heads: flat, domed, conical...I don't see where your equation deals with that.

Also when I make rivets will size the head for the task, so for one job the head may be quite large and for another quite small---standardization seems more suited for factories than for craftsfolk who are doing custom work!

Posted

Good point on the types, I was going to mainly deal with the dome to begin with. As far as the other, this more or less gives someone (like me) that place to start from to build their skill level. I would hate to make a set of tongs just to find out that my rivet wouldn't hold up then find out after many tries that I was making it way to small for it's purpose. Thank you for your input.

Posted

What happened to 1 1/2 diameters for a typical flat head? Making tongs you size the rivet 3 diameters longer than the required grip length so each head gets 1 1/2 diameters.

Phil

Posted

The 1.5 shank diameter is a general rule for cold riveting. For hot riveting, you can have some more length. On my tongs, I hot rivet leaving 2.5 for a head, because I want a broad rivet head to lessen the slop (you'll have some slop).

My sixth edition, 1953, British book has some dimensions of manufactured rivet heads. They call a round head a "snap head." The head diameter is 1.75 the shank D. The head height is .75D. The flat head is 2D of the shank D. It's height is 1/4D. The brazier head is a low profile dome. Its head is 2D the shank, and its height is 1/2 shank D.

reference: "Handcraft in Metal" by A.J. Shirley and A.F. Shirley. Lippencott, Philadelphia - New York

http://www.turleyforge.com

Posted

Good point on the types, I was going to mainly deal with the dome to begin with. As far as the other, this more or less gives someone (like me) that place to start from to build their skill level. I would hate to make a set of tongs just to find out that my rivet wouldn't hold up then find out after many tries that I was making it way to small for it's purpose. Thank you for your input.


Failure on tongs is more likely due to innappropriate diameter of rivet used and boss size where it is rivetted through,
Posted

mmm..... I have always used the "Looks bout right" method....


You're not alone. Too much overthinking tends to hurt my head. Not that thinking is a bad thing but the "Looks bout right" method works for me. When it doesn't, make it bigger or smaller next time.

Granted, some things need to be well thought out so as not to waste material, cause multiple attempts on a time sensitive or cost restrictive project, avoid injury, etc.

Glad there are those of you out there that have the brain cells for figuring these things out.

Mark<><
Posted

When it doesn't, make it bigger or smaller next time.

Mark<><

Bigger = you get some welding practice & Smaller = you get some grinding practice, thus both good :D

Can't fault the boys! B)

Ian
Posted

You're not alone. Too much overthinking tends to hurt my head. Not that thinking is a bad thing but the "Looks bout right" method works for me. When it doesn't, make it bigger or smaller next time.

Granted, some things need to be well thought out so as not to waste material, cause multiple attempts on a time sensitive or cost restrictive project, avoid injury, etc.

Glad there are those of you out there that have the brain cells for figuring these things out.

Mark<><



Yea well with this **** burn ban, all I can do is think and wish. lol When your not sure what the "bout right" looks like you kinda of need something to go off of. I was just using tongs as an example because that was the first most common thing that came to mind.
Posted

Well, the rivet in a pair of tongs has much different requirements than a rivet in a structure, so the parts to rivet relationship will change. In tongs there is only a single rivet and it is loose so it will be relatively larger than the multiple tight rivets in a structural assembly. Tongs are a very special purpose rivet and may be the worst example to generalize from.

Old Machinists' Handbooks and engineering books have rivet formulas for lots of different situations. That's where I'd start for formulas. Here's a link to one in google books: http://books.google.com/books?id=4Q8LAAAAIAAJ&dq=Colvin%20%22American%20machinists'%20handbook%22&pg=PA315#v=onepage&q&f=false

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