Tong Question

[jayco]

Is there a mathmatical way to predict or measure the grip of tong jaws?
Is it as simple as a ratio?

What I mean is; if you have tongs with 10 inch handles, and one inch long jaws(or bits), is the pressure put forth on the jaws roughly 10 times the pressure put on the handles(or reins)?
(allowing that it was possible to put all the gripping pressure exactly at the 10 inch point on the handles)

Would a 10:1 ratio be correct on this?

I'm just thinking out loud on this........but, what do you guys think?

James

[imagedude]

Your theory is in the right ballpark but how often do you grip the tongs near the end of the reins?

[Frosty]

James:

It's a straight ratio, same as any lever or gear train. It is of course to be exact because a grip covers a length of the reins and the stock is held by a range of the jaws.

Regardless you have it right.

Frosty

[Mills]

If you use a tong clip then for practical purposes the force is duplicable and singular.

[Frosty]

If you use a tong clip then for practical purposes the force is duplicable and singular.

Yes. Provided the jaws contact the stock in exactly the same place as well. Any deviation at the jaws will result in a greater difference in force than deviation at the reins.

Happily, smithing isn't in need of pecision measurement of forces in this way. It's fun to play with though.

Frosty

[jayco]

Here's a couple of pics to illustrate why I asked the question.
This is a pair of v-bit/bolt tongs I made some time ago.
I was always puzzled that they didn't grip the way I expected them to.

As you can see, it's 5 and1/2 inches from the rivet to the end of the jaws.
From the rivet to the end of the reins, it's about 16 inches.

So, the ratio would be:

16 to 5.5
or.....3:1........more or less.

But you get my point I,m sure.

The jaws are so long that the current rein length only allows the grip to be multiplied 3 times!

I guess this is something to keep in mind next time I make tongs!

James

[mcraigl]

James,
I love the goosenecks when I need them, but when I don't, I use tongs with about a 16" rein, and the jaws only stick past the rivet about an inch. This is for exactly the reason you're playing with. Especially on the Power Hammer, I'll use the shorter jawed ones if possible AND a tong ring.

[Mills]

Tong rings are our friend. as is short jaws.

Struggling with some 1 1/2 " S-7 on the power hammer drawing it down I used a set of goose necks I made that had the jaws break off. I had thinned them too much. Tried them out as Clifton Ralph and others have demoed and that really made a believer of me for pincer type tongs. Will be making some more soon.

Jayco one thing I tried to do in my tong making was to duplicate Grants off center tongs. That is a the wrong way6 for me. I now start with 5/8 rd min stock size up from 1/2. I will draw the reins down to 3/8 rd. This is more in line with old tongs and I find they last longer for me. heavy jaws light reins big rivets and 18" length or more.

I do regularly work with heavier stock but I also will use the same approach scaled back for 3/8 and smaller. I'll use 1/2 rd and smaller rivets but still keep them 16" or more. With a tong clip I can then grab at a balance point and it forges nicely.

Lastly, in production on small hooks and leaves, OC tongs are the only way to go. no tong clip cause things are happening to fast for that. that is where the light weight short length shines.