More rubber press forming ideas

[DRLPatrol]

Don't post much because most everything I need to say has already been said a whole lot better. I will share this though because it works great and is cheaper than others have used. I wanted to try rubber press for the lightning holes in the ribs. John Snapp did a great video of the process, I think it was he that said what rubber he used and the source but being a tight a$$ I wanted to try something else. Farm stores, Coastal and Wilco in the NW, Tractor Supply in the East, sell mats for horse trailer and stall floors. I wanted 3/4" but the only 3/4" they had was in huge sheets and they had 3/8" by the foot. I paid less than $10 for a piece 1' by 4' and use 2 layers.

[Robert440]

Are you using one size die for all the round holes? Looks good.

[Chewie]

Very nice. Is that stuff like regupol - basically recycled rubber?

[DRLPatrol]

The "die" is just a round scrap of 3/8" plate a little over 7" in dia. Yes same for all holes. Wish it had been 1" x 8", then I would not have needed the other piece of steel to spread the load out.

Yes, recycled rubber. I was afraid that it would start coming apart, but after a couple of changes in the procedures the same pieces are going to finish the whole set of ribs. About 1/2 the flap ribs to go and I will be done. The 3/8" OSB spacer in the bottom of the hole that you are pressing keeps the rubber from having to stretch so much. Also I started at 15 tons then found 10 tons did the same thing and was not as hard on the rubber. At 15 tons I was also starting to slowly warp the 3/8" plate. The bigger the die is the more tonnage you would need.

Doug

[Chewie]

Very cool Doug! I just turned out my first center rib flanges yesterday (in a 27 degree garage). It's strangely exciting to step back and look at something that looks like an airplane part where before all you had was 2D sheet metal, would you agree?
I'll be experimenting with dies as well. I posted some photos on dropbox, the link is under my profile page if you're curious. I notice you don't have a backer on top of your rib - seems to be working well without one?

[DRLPatrol]

Yes it is cool when they start looking like parts. I hear you about the temp, the wood stove in my shop has been going around the clock for this cold snap.
By backer you are talking about the top MDF with the hammer method? If so, no, the rubber on the flat part of the die was more than enough. I used NAS #10 screws with a very thin head as jig pins to pin the rib to the jig ( to keep your flange centered on the lightning hole). The rubber did not seem to care about the screw head.

Doug

[S Lathrop]

Here is a picture of how I did the lightening holes in my ribs.

The disk and rib former are .125 aluminum plate. The rib flanges are formed on separate form. The wood is high density particle board and fits inside the formed rib. The notches in the side of the wood are to clear the flutes on the rib flanges. The rid lightening holes are formed by placing the round disks on onside of the rib and the larger female form on the other side of the rib. The rib is formed by pressing the wood blank on the inside of the rib against a flat surface, made from more particle board.

I used this method so that the ribs were flattened when I formed the flanges.

It seemed like there is a lot of tooling but once the tooling is made, the flanging was done in minutes per rib. I think I saved time overall. This is the only job I used my fly cutter for, cutting the 1/8 plate. The cutting tool was the exact size to form the bends.

[Chewie]

I'm just using MDF dies, there is scrap aplenty! They seem to work well except my circle cutter couldn't quite make a 7" plug for holes A and B (diameter plus 3/4") - had to jigsaw that one.

After doing the side flanges I will swap the blocks and use the form block BACKER as a female for the holes. It's slightly smaller than the master form block and clears the flutes along the sides.


Setup for hole flanging.jpg

I noticed only the .025" ribs get hole flanges. Is that because the .032 webs get the extra stiffness from being a thicker material? That saves me having to make a die for the dashed oval hole on the back of the center ribs.

[DRLPatrol]

Mark, If I understand you right, your making your hole in the die 7". I used 6.25" and routed a 45* chamfer on that so the outside of the chamfer is 7". That way you can't bend the flange to far. With spring back it is close to 30*

Doug

[Chewie]

No I still made the female die (the bottom piece) at 6.25" and chamfered it out to 7" like you did; but I used a backer (the top piece) which had to be 7" in diameter to accommodate the male plug.

[DRLPatrol]

OK, I'm with you now. I was thinking rubber press instead of the plug die way of doing it.

Doug