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wrongway john

Well Known Member
Although C-frames work well, wondered if this would give us better consistency on dimpling and setting rivets. Take your existing C-frame, but set it up with a longer bar, say five foot, and a slightly stronger spring. Put a weight (3 lbs or so, not sure yet) similar to shape that body shop hammers have that pull dents and has a hole that runs through the center of it. Also have it adjustable where you add or take off smaller weights. Raise weight to a height that also has various heights to drop the weight from, let go, and let gravity do the rest. The weight would hit a part on the lower bar like a welded nut which drives the dimples and rivets with our standard sets. I hope this description gives one the basic concept. Have others considered something like this and do you think it would work? Seems like it would work well, but what do you think?
 
the dimples i make with the c frame all look the same to me, maybe you aren't hitting yours hard enough? in other words, the only difference in dimples would be if you hit the skin to lightly. other than that its a relatively simple procedure to make them all the same with no weight contraption


rivets get set with a gun in the c frame if i am using it, no way i'm going to a hand operated weight to smash rivets
 
I think that's an interesting and inventive idea, if your objective is to experiment with different ways of dimpling and setting rivets. Otherwise, I'd say it's a solution in search of a problem. I think every dimple that I've ever made with my C-frame has looked exactly like every other dimple. If you're not getting consistent results dimpling with your C-frame, try just giving it two sharp smacks with a mallet, you should get very nice, crisp dimples.

John
 
C-Frame Use

You really need multiple hits to get a consistent dimple, like bending a piece of metal in a break, it pops back a bit. The reason the DRDT is 'more consistent' is the built in stop and compression action rather than impact. As others have mentioned the impact type tool is just as fast and consistent (but louder) once you learn what to feel or listen for. I just uploaded a section of video to YouTube that we have used in our builders classes. You want to hear a bit of a ping on the second hit as the two dies seat together. You can hit it too hard and get a clang, practice for a few dozen dimples and it is very repeatable.

See: http://www.youtube.com/watch?v=q7MnuSDrey0
 
Thanks for the feedback, and Mike especially for that 6 second educational video, 6 seconds well spent. That second sound is what I?ll be listening for, and have decided to do mine in two hits like that.

Speaking of the DRDT-2, that reminds me Greg to get back with Paul. I think I'll use one of them as well, just to experiment around with the various ways of doing things.

I?m not really having any trouble with my Avery light weight C-frame, quite happy with it actually, but I?m just barely getting started, and just a little timid. Getting closer to start riveting my first rivets in the empennage on my 4. Mostly been reading from others on what they do, and some talked like the much bulkier and heavier steel C pneumatic presses did some of the best and consistent dimples and rivets on their skins. I just figured a simple weight could give the same consistency without the expense and complexity.

If you guys can?t tell the difference between your rivets done on a basic C-frame and theirs done on the heavier duty equipment; then, I?m sure that?s good enough for me too.
 
Make sure your C Frame is supported well.

A common problem is not having adequate support under the C Frame. Even the flex of a table can cause a poor strike. The C Frame should also be bolted down to prevent it from "bouncing".
The reason the arm is the length that it is has a lot to do with the flex of the C Frame. A longer Arm could allow too much "flex" during the strike. You are concentrating a lot of power on a very small area, even with a relatively light blow.
You can get away with just setting your C Frame on a table. However, you would be surprised how much easier and cleaner the dimple if you can make a good solid strike.
 
JonJay said:
A common problem is not having adequate support under the C Frame. Even the flex of a table can cause a poor strike. The C Frame should also be bolted down to prevent it from "bouncing".
The reason the arm is the length that it is has a lot to do with the flex of the C Frame. A longer Arm could allow too much "flex" during the strike. You are concentrating a lot of power on a very small area, even with a relatively light blow.
You can get away with just setting your C Frame on a table. However, you would be surprised how much easier and cleaner the dimple if you can make a good solid strike.
Click to expand...

I agree-
I have a solid table, real 4x4 legs and 3" of engineered wood for the table. it doesn't move when the c frame is on top of it, and i use a deadblow hammer to transfer energy to the dies
 
Jon Jay, you?ve talked me into moving everything onto my welder?s table. That ought to make for some real nice dimples and riveting. Best $20.00 I ever spent. Now if I only found deals like that on all of my other aircraft tools and needs. :D
inws2t.jpg
 
It really helps with the c-frame to hold the shaft down so the dies are against the skin, then strike it with a mallet. A also hit it twice.

I also have DRDT-2, but perfer the c-frame. I only use the DRDT-2 for ribs ect, but I like the c-fram more for skins.
 
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