New Plans Built Plans Holder

[N3UW]

Welcome to the forum. I used a 20 ton press with rubber matts from mcmaster carr to form the lightning holes in the al ribs. Worked great. Have some videos on youtube that show my process. The rubber i used was Amber Polyurethane Sheet 1” thick 60a and

High-Strength Multipurpose Neoprene Rubber, 1" Thick, 12" X 12", 50A Durometer

you need two sheets. I used one of each. You could use two of either. The neoprene is cheaper but the poly worked a bit better.

here is the you tube channel https://youtube.com/@n3uw

[sjt]

I used the same method that N3UW recommended. The amber 1 inch sheet is the one I found most useful. I think the amber one should be in contact with the aluminum and the black one on top of that.

Even so you you need all of the 20 tons to get the result you want.


His video on building a torsion table is also something I replicated.
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If you make his torson table design you need a fan to blow the dust out into the neighbor's yard.




I added an array of 1/2 inch nutplate analogs to his table design to have an array of built in clamp locatons.

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When you attach capstrips to spars you need outriggers to be able to work fom both sides of spar.


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I can bolt to an array of locations.




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[sjt]

I found the torsion table to be very useful

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[sjt]

I thought John had a video but I guess I saw it on the forum

https://bearhawkforums.com/forum/bearhawk-patrol-plans-build/4028-getting-ready-to-build-the-spar#post4473

[sjt]

I am pretty lazy. I added a vacuum system to John's design and plumbed my vacuum into the table.

I then added a remote control switch so that I could turn on the vacuum without getting out of my chair.

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v.jpg I exahaust the vacuum outside

The outlet box needs a contactor because a vacuum pulls to much current.

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I then got a chair with wheels so I could roll from one location to another.




As you can tell I am very good at doing anything other then building my airplane.

[SpruceForest]

If you do the fuse first...

Another good reason to have a 20 ton press...lots of 4130 work to do. You can home-brew a finger brake or spend another $500 on ready to go to work (or do the welding yourself and some about $150). The SWAG Offroad MIA finger brake for the HF 20 ton press is one of those 'if you can afford or borrow it' sort of things that makes all those U-brackets pretty fast and easy, as well as gets you some welding practice on beefier stuff. Eastwood makes a cheaper version that runs closer to $300, although we will see how long that holds up re: tariff-related price increases.

There is a small amount of welding and bracket fab in the wings, and way more of it in the fuse, LG, and the tail. Because I was producing all those brackets for two airplanes, I systemized the work and used some 1018 steel plate and bar stock to do the rams and bottoming dies for the press. makes forming those landing gear brackets with odd angles and cutouts way easier. Also one way to press out those longer 4130 structural closeout shapes such as the U that closes out the for and aft upper MLG legs.

And one of the enduringly cool things about the bear hawk is this can all be done with vise, form blocks, a good set of mallets, and some elbow grease if you want to forego the expense.

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A partner tool to the finger press is a portable bandsaw (Milwaukee, etc.) in a router table... I've cut 1" steel and nearly all that 4130 needed after some quick dimensioning with a cutoff wheel on a grinder (get a good larger sized grinder and a couple HF 4.5" cheapies (Warrior in my case) cheapies which can be left set up for flap wheel trimming or ball end mills. I bought the best HF portable and their horizontal bandsaw/table combo for about $300 on sale... great buy and handles stuff that would take a good long time with other methods.

[sjt]

The HF coupons only apply to a single item. The best usage of a single coupon is their 1 inch belt sander.

Get belts on amazon as you need them.
Fine grade for 2024
coarse for 4130


If possible wait for it to go on sale and then use coupon.




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[sjt]

Home depot and amazon sell the 6x6 rubber plumbing repair material

cut out circles and rubber glue them to the 2 inch clamps to protect 2024 when clamping

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The bar clamp comes with protective shoes.

[sjt]

Now that I think about it you might hold off on the clamps until you give some thought to your work area.

Those clamps worked for me because my table was a mdf board supported in such a way that I could work on the back side at the same time.


The clamps fit thru slots cut thru the mdf board.

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My plan was to use a c-frame to back rivet by sliding under support mdf slotted board.


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For this final operation the mdf slotted board is removed and the spar is accross the 2x4 overhang



If you have a helper you might just have them hold a bucking bar while you rivet with spar held vertically.