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workspace considerations for dimpling skins on the -14

ryane67

Active Member
So I'm finalizing my workshop and I was thinking about where I would put the DRDT2 (or c-frame, whichever you prefer) and I realized I didn't know how much space I would need on either side of the dimpling machine because I don't know what the biggest (longest?) skin is that we have to dimple for this plane.

I'm thinking that 3-4ft on either side of the dimpling fixture should be enough, but I want to be sure. If those dimensions don't work then I'll have to keep the dimpling in the "secondary workshop" AKA wife's portion of the garage... and we all know that doesn't always work long term.

can anyone tell me the length of the longest skin we have to dimple for this plane?

Thanks
 
Portable

Dimpling is done occasionally only, so rather than a fixed setup, have you considered using a narrow portable stand for the dimpler? That is what I use (for my -6A, which is smaller than a -14), along with two six foot folding tables that get set up either side of the dimpler. It works very well and takes up little space when it's not being used.
(3-4 feet is probably not going to be enough for the wing skins and some of the fuselage skins.)
 
Dimpling is done occasionally only, so rather than a fixed setup, have you considered using a narrow portable stand for the dimpler? That is what I use (for my -6A, which is smaller than a -14), along with two six foot folding tables that get set up either side of the dimpler. It works very well and takes up little space when it's not being used.
(3-4 feet is probably not going to be enough for the wing skins and some of the fuselage skins.)

Not a bad idea. I was saying 3-4 feet on both sides, so 8 or so total.

I definitely don't think it'll be a fixture in the workshop, more set up and torn down as needed so your idea is a good one.
 
6 or 8 foot table worked for me. I slid the dimpler Lt & Rt down the table as needed so sheet never over hung the table dangerously either end. I also used 2 small plywood platforms (1' x 2' spaced vertically with 2x4s) to keep the sheet horizontal, also slid them around to best stabilize the sheet as needed.
 
I found a rolling cart to be helpful keeping the long empennage and wing skins from hanging too far unsupported.
 
If your dimpler is fixed I would think you need 15-16 feet space. A better idea is to just move the dimpler around the table (I screwed it down) and use little tables to hold the skin up. This post shows the dimpling tables - they have carpet on them now.

This blog entry has a pic of one of the longer top skins on the bench being dimpled to give you some idea.

By far the hardest thing to dimple is the horizontal stab skin - I found the best way was to hang it over the edge of the bench so the skin went under the bench - and the male die on the top. This post shows a pic of how I did the HS skins.
 
Bench set up

Mine was like Ty above except...
I use EAA benches. Easy to move them around. The platform and C-frame were not permenant so everythjng could be arranged to fit the job.
 
Thanks for all the tips everyone!

Looks like I've got some more ideas to consider placement and surrounding infrastructure.

I might try and create some sort of modular tabletop out of Foamular insulation board that sits ontop of whichever workbench is in use at the time and matches the dimpling level of the DRDT2 so it can be lightweight and easily setup/torn down and stored in relatively small amount of space.
 
When I built mine, I had two slots for the dimpler, 1/3 in from either end. This made it easier to dimple the ends of big sheets.
 
Lots of good ideas here ... for the heavy DRDT-2 I made a 2x2 rolling stand with lockable casters of the same height as my 2 EAA workbenches. The same, but without casters, for the lighter C-frame riveter. A very flexible setup that gave good support to everything regardless of size or shape.
 
I use an adjustable height rolling table from home depot to clamp the DRDT2 and then another workbench to lay the skin on.
 
"The use of a bit of tube over the rivet also helped keep the flanges flat onto the rib."

interested in this process. Would you have a pic or could you elaborate. Thanks in advance.
 
Mine was like Ty above except...
I use EAA benches. Easy to move them around. The platform and C-frame were not permenant so everythjng could be arranged to fit the job.

I did the same thing as well. Works like a charm to optimize space.
 
Tube over rivet end

PatMac,

I couldn't find the original post you referenced, but I believe this is a similar technique to the tube referenced. I used small “O” rings over the rivet tail. The squeezer (or bucking bar) compresses the two flanges together before the rivet sets to aid in a tight fit. Nice to have when you have 10 rivets completed and one piece of metal that doesn't want to stay perfectly flat..

The image is just a set-up to show the washer and is not representative of actual surfaces to be riveted.
 

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Another technique

PatMac,

I couldn't find the original post you referenced, but I believe this is a similar technique to the tube referenced. I used small “O” rings over the rivet tail. The squeezer (or bucking bar) compresses the two flanges together before the rivet sets to aid in a tight fit. Nice to have when you have 10 rivets completed and one piece of metal that doesn't want to stay perfectly flat..

The image is just a set-up to show the washer and is not representative of actual surfaces to be riveted.

For a similar task, I used a strip of very high density foam rubber (about 1/4” thick) attached to the bucking bar. The rivet would push through it and the foam would push the flanges together before the rivet began setting.
 
PatMac,

I couldn't find the original post you referenced, but I believe this is a similar technique to the tube referenced. I used small “O” rings over the rivet tail. The squeezer (or bucking bar) compresses the two flanges together before the rivet sets to aid in a tight fit. Nice to have when you have 10 rivets completed and one piece of metal that doesn't want to stay perfectly flat..

The image is just a set-up to show the washer and is not representative of actual surfaces to be riveted.

I have never understood how this works. Doesn't the o-ring need to be thicker than the rivet tail is tall (so its squeezing the two pieces together)? I've tried making tubing thicker, but the bucking is always ugly. What am I missing?
 
Agreed, the image I posted was just some components I had at the house. Everything else is at the hanger. The O ring should be roughly the same height as the rivet tail at the start. As it squeezes. Everything gets pushed together.
Try some samples and see how it works.
 
This is going to raise a few hackles. But, I keep my DRDT2 on the shelf, and pull it out and attach it to a temporary table top that is clamped to my ShopMate portable work table. No outfeed tables or supports. So far, when I've used the DRDT2, this is how I've done it.

https://youtu.be/i6ljOVNIGoI
 
There are only ~40 skins on an RV that need to be dimpled and (in general), you're only gonna be dimpling a couple of them at any one time. I didn't see the need to invest in a special fixture or dedicated workspace - I just put the dimpling tool on the shop floor and used whatever materials were handy to create a surface that was relatively level with the bottom die. Old phone books (remember those?), Harbor Freight packing blankets, etc. Whatever was necessary to achieve the proper height. Then I sat on the floor and pounded dimples for a few minutes on each skin.

Yeah, I know. It is barbaric. But my shop isn't cluttered with "one more" special table/tool, and I saved whatever time it might have taken to build a dimpling fixture. Now, if I was a pro builder or a build assist shop, I'd have one at an appropriate working height. Otherwise, not an efficient use of my time.

Unless you have unlimited time, there are forks in the road where you need to decide if you're building an airplane or a shop. ;-)
 
Dimpling

IMO, there is no substitute for some help in the shop when dimpling the bigger, more cumbersome parts. Twice now I put an extra hole with the dreaded C-frame dimpler that I don't think would have happened had I been patient enough to get another pair of hands involved. Last one was the left fuel tank skin and that jewel cost over $300 with shipping...
:cool:

JET
 
I made two EAA benches a long time ago. I made a sturdy 2x4 based frame on the end of one that gets the DRDT-2 work right at table height plus a little allowance for the toolchest liner I put on the table while dimpling. The dimpler can unbolt easily from the bracket and be put away. For small stuff its on a table.... for big stuff I drag the other bench over and the DRDT ends up between them.
 
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