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View Full Version : Rivet closing - advice please...



Davek0974
01-12-2009, 04:58 AM
Hi all,

I am trying to find the force needed in lbf to squeeze-close a 1/4" iron rivet cold.

I need to make an air operated pair of closing tongs to fit the strakes on the back wheels of a traction engine i'm building. A hammer and anvil cant be used.

The tread side of the rivet is flat and in a countersunk hole, the inside is standard snap shape.

Thanks in advance

Dave

Circlip
01-12-2009, 06:29 AM
I think MEW did a "Tong" (Squeeze) type closer, want me to look??

Regards Ian.

Davek0974
01-12-2009, 07:39 AM
Yes please Ian, that would be much appreciated.

Thanks

Dave

Circlip
01-12-2009, 07:48 AM
Oh Bu**er!

Mcgyver
01-12-2009, 09:33 AM
I've not done this particular task, 1/4 steel rivets cold, but was struck that it is going to take a lot of force to close this rivet that might make a tong mechanism would a challenge. I guess it would be tough to do hot, given there's a lot heat sink material around.

Have you considered a press? The presses I have seen for use where you can't hammer look like super heavy duty C clamps; almost like circles with a slot cut in the middle. Have the fixed jaw on the inside (may need different formers that insert in the jaw and that form the head in steps) and jaw with the screw on the outside......or if that's not heavy duty enough have the inside jaw again fixed and the outside jaw hydraulically closed. The part of the the C clamp that would normally carry the threaded part instead carries a piston. If you had say a 1/2" floating cylinder and then a smaller screw in cylinder compressing the fluid you'd gain hydraulic advantage.

Davek0974
01-12-2009, 09:54 AM
Hi,
yes, a c-clamp type thingy sounds good, i was wondering if a small hydraulic car jack would do? They are easily 5 ton capacity and quite small too.

Question is, how strong does the frame need to be? I have very little heavy stock so i will need to purchase some, and really dont want to be throwing money away.

Thanks

Dave

huntinguy
01-12-2009, 10:30 AM
http://www.assemblymag.com/Articles/Feature_Article/BNP_GUID_9-5-2006_A_10000000000000220240

From the article: "A small single-cylinder tool with an alligator yoke weighs 3.75 to 4.75 pounds; applies 1,800 to 3,000 pounds of force; and upsets aluminum or steel rivets up to 0.0937 inch in diameter. A large two-cylinder tool with a C yoke might weigh 15 pounds and apply 12,000 pounds of force. It can upset aluminum rivets up to 0.25 inch in diameter or steel rivets up to 0.2187 inch in diameter."


Looks like it could be quite a bit. :eek:

A little math should give a value for the thickness of steel required.

Evan
01-12-2009, 10:59 AM
Sounds like a job for some modified cheap import bolt cutters.

Circlip
01-12-2009, 11:20 AM
Found them Dave, will scan and send to your E-mail.

Regards Ian.

Davek0974
01-12-2009, 11:21 AM
I'm liking the ideas so far.

It seems a c-clamp style would be best with a cone tool to seal the base of the rivet and a flat tool to finish off.

I'll start looking for some scrap bits i think and a spare 10 ton bottle jack.

Thanks so far

Dave

Patch
01-12-2009, 11:27 AM
We install rivets of varying dia's from 1/4" to 3/4" in trencher chain.
Certainly not good when you are into a trench 6' and a pin or rivet come loose.

Had very good luck using an air hammer rivet tool.
I really like the center pin punch type as it not only pressure loads bore but also spreads the rivet end as to a mushroom.

The flat type gets a bit of use as well when securing the larger rivets.
These are all installed cold and without heat.

I know a lot of you guys like Harbor Freight so I posted a few links to inexpensive riveters.

http://www.harborfreight.com/cpi/ctaf/Category.taf?CategoryID=328

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92037

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=97857


Patch

DR
01-12-2009, 11:30 AM
http://www.hansonrivet.com/w84a.htm

This might give some indication of the difficulty of setting 1/4" steel rivets. Making a tool would be quite a job.

Mike Burdick
01-12-2009, 01:14 PM
Dave,

Here's a hand rivet setter that is used for setting solid steel rivets on hay mowers and it works well. I have one and paid around $30.00 for it at a farm supply. I know you didn't ask for information on one that is made but perhaps you can adapt the already made dies and anvils for your use as these are very inexpensive ....

Here's a link to one that can be purchased online.... http://www.smithtoolinfo.com/upload/stimages/R3030right.jpg

http://www.smithtoolinfo.com/r3030.htm

ProGunOne
01-12-2009, 01:39 PM
Sounds like a job for some modified cheap import bolt cutters.

I agree. Some of the gun building crowd do just that to set steel rivets when building the Klashnikov (AK type) rifles. I can probaly locate a photo of a modified pair if you'd like?

agrip
01-12-2009, 03:32 PM
Assuming a 45,000 psi effective crush strength, 2210 lbs squeeze, will start the mushroom.
Because of the unknown mush room size, might take 5000 pounds force or greater to finish it.

design conservatively to allow for "Murphy" to twist and turn a bit.
Hth Ag

Davek0974
01-12-2009, 03:42 PM
Thanks to all so far, great suggestions.

I cant yet see bolt cutters doing the job, the strength will be lost by increasing the throat depth enough for the job?

So far i have found some 4" x 3/4" steel plate long enough to make a c-clamp style tool with a single spine and double base / top arms. I have no drawing software so i hope a thousand words will speak as much as a picture:)

The maximum throat depth needed is 3.5", i could vee out and mig weld the joints or would bolts be strong enough??

It would likely be used lying on its spine with the wheel mounted horizontally on a support so it can rotate, i'm guessing the jack will need to be overfilled with oil to allow it to work in this orientation.

Someone has already suggested using a centre drill for the countersinking as the angle makes it easier to make the rivet fit compared to a countersink bit. The rivets are domed on the inside of the wheel and flush on the treads

Its still early days...

Dave

Davek0974
01-12-2009, 03:55 PM
Assuming a 45,000 psi effective crush strength, 2210 lbs squeeze, will start the mushroom.
Because of the unknown mush room size, might take 5000 pounds force or greater to finish it.

design conservatively to allow for "Murphy" to twist and turn a bit.
Hth Ag

That sound less than i was thinking, 5000lbf is about 2.5tons (i think) so a 10 ton hydraulic cylinder should do some serious squeezing:)

I'm not used to designing high strength stuff, could a c-clamp style tool with a spine length of say 20"oa and throat depth of 3.5" be strong enough if made from 4" x 3/4" steel plate?? Actual material is unknown but ive been given 5' of it and it took three people to shift it!

Dave

camdigger
01-12-2009, 07:23 PM
Dave

The dimensions of the Smith rivet tool and the like are minimum 3/4" and, I think they're drop forged steel. A strip off your 3/4" plate should do if you leave enough meat at the base of the throat to prevent spreading. I suspect the forming head on the end of the bolt is heattreated for toughness and resistance to mushrooming too. IIRC, the thread is about 10 TPI. The thread is a compromise between mechanical advantage (increases with TPI) and strength (decreases with TPI).
I've used similar tools with a 1/2" impact and socket.

My $.02 cdn
Cam

Davek0974
01-13-2009, 03:15 AM
Thanks all,

My home shop drop-forge is down at the moment :) so I think i'll go with a single 4"x3/4" spine with two plates of the same each for the head and foot. The head/foot plates can be recessed to a half-lap joint at the spine so they effectively form a 1-1/2" x 4" block, welded to the spine all round.

As i said, its early days but at least i've got and idea now.


Dave

Circlip
01-13-2009, 03:56 AM
Did you get the articles????

Davek0974
01-13-2009, 04:11 AM
Did you get the articles????

Yes, many thanks, what i have read so far is very interesting



Dave