Would Airplane Builders Be Interested in a Pneumatic Dimpler?

[cgrossl]

You all bring up some good points. I do wonder if 300lbs will be enough. I must also clarify that I am working on a dimpler only, not a riveter. I also wonder how much my C-frame will flex. But, there's really only one way to find out and that's to try it and see. I actually look forward to being able to design and build something to see if it will work, then, getting to refine the design. I'm used to getting one chance. I work for a company that designs and builds custom machinery, mostly for automotive manufacturers. One week, I'll be designing a weld fixture then the next week I'll be designing an 80 ton, air over oil press, complete with tooling and auto part loading and unloading. Working for this company gives me access to an awesome machine shop and allows me to purchase steel and pneumatic components at OEM prices.

Designing a machine to do a specific function is nothing new to me, but bringing it to market is, and that's where my hesitation lies. Right now, I plan to build a working prototype, test it myself, then let a few local builders test it out. I also have an idea that would all but eliminate missing the rivet hole with the dimpler, but it would require a custom set of dies, which could be a good thing and it could be a bad thing.

[Mike S]

Someone else tried the same thing a while back on this forum-------I.E., "testing the waters" for a pneumatic dimpler.

As I recall it wasnt well recieved. First rendition had one cylinder, then he added a second. Was talking around the $500 area. Foot pedal valve unit was low end, needed a "Teasing" valve.

If I remember correctly, the unit was an add-on to the DRDT-2.

I tried searching for it, no luck.

If you are going to develop something like this, I wish you good luck.

I think the market is out there, price and quality will be the determining factors, IMHO.

Mike

[RV7Factory]

Originally Posted by cgrossl

Anyway, during all of this research I found it surprising that the most accepted methods of pressing dimples in a piece of sheet aluminum are with a hammer and a C-Frame jig to keep the dies aligned, or with the pull of a lever.

Cameron, while I believe there is always room for innovation, don't downplay the advantages of the hammer or lever-methods. Both require no noisy compressor, and the lever method (e.g. DRDT-2) is near silent allowing us to build away in our garages into the wee hours of the night w/o waking family or neighbors. Just food for thought. Good luck!

[cgrossl]

Brad,
I'm not trying to downplay the regular methods of dimpling panels, but I can see where you might have taken my initial post that way. It just really surprised me that no one had brought a more automated way of dimpling panels to the market. By nature, airplane builders are innovative people and what I'm proposing is a very simple idea. I did find some instances where individuals had made working, one off, dimplers, but I didn't find a commercially available, fairly inexpensive unit.

I've not got a whole lot going on right now so this idea has been running around in my head for a while now. I think that I can do this for the price that I gave in my initial post. We'll just have to see if I'm right. I may be trying to tackle way more than I am thinking.

[rv7boy]

Cameron,
It's not just the force but the rate at which the force is applied. The dimpler (Ole Yeller) I referred to in my previous post had two BIMBA cylinders which were, IIRC, 1 1-2 inch diameter cylinders. If my math is correct, that's about 1.8 sq inches per cylinder and at 80 psig shop pressure, that results in a force of a little less than 300 lbf. By adjusting the air pressure with the pressure regulator, we could get a quick WHACK or a more gentle TAP. I can't remember the exact air pressures, but my shop air pressure can be regulated up to 125 psig, and I never had to take it that far.
I wish you well, but I really think that as many C-frames as there are out there, you would be able to market a retro-fit kit better than a new dimpler using a new frame.
But hey! What do I know? I'm just a rocket scientist!!!
Best wishes,
Don
Also, you should consider the safety of such a device. As smart as we are , there's always the possibility that someone could try to dimple their finger!
Having used a pneumatic dimpler myself, I will say it's easier to do that with a pneumatic dimpler than with a hammer type.

[DanH]

Don,
How about posting some pictures of Ole Yeller? Might put one in the queue for right after I finish the propeller duplicator <g>

Dan

[rv7boy]

Originally Posted by DanH

Don,
How about posting some pictures of Ole Yeller? Might put one in the queue for right after I finish the propeller duplicator <g>

Dan

Dan,
I'm not in possession of Ole Yeller anymore, and I'm not sure I have photos. I will look when I get home and if I have some photos, I'll see if I can post them.
Don

[gmcjetpilot]

Buying a pneumatic squeezer, dimple or rivets is one of the best tools I bought, but I think it has been done already. Good idea though

[captainron]

Okay, here's a question for the rocket scientists out there. How many unwanted dimple holes does it take to ruin a skin? My guess would be "one", but why not have a way of insuring against even that? I'm too stupid to do it, but I'd like to see someone take a regular male dimple die, and put a tiny hole through the center of the pin for a tiny fiber-optic light. There would be a reciever in the other die, and an electrical lock-out solenoid on whatever kind of dimpler you are using. If the hole isn't aligned over the pin, no dimple! Oh well, yeah, I know, dumb idea......

[cgrossl]

Don,
I like the retrofit idea. But, from the regular C-frame pictures that I have seen, the structure looks pretty flimsy and my calibrated engineering eye (yeah right) tells me that a 300lb force that trys to open the c-frame up would cause quite a bit of flex. Did Old Yeller flex alot during operation? The bracketry that would be required to do the retrofit would be extremely simple to design and manufacture.

As far as safety goes, yes, there is a major pinch point that would have to be guarded by a simple clear plexiglass guard.


Ron,
I have an idea for a mechanical way to ensure that the operator doesn't miss a hole while riveting. But, I figure that I'll see if what I've got works before I go down that road.