JD2 Model 3 converted with a HF air/hydraulic cylinder

[buildstoys]

After waiting for a month, my Harbor Freight air/hydraulic cylinder finally came.

For $80 , some scrap metal and a couple hours of time, I've converted my JD2 model 3 bender.

I've got some "build" photos and a short video.

The cylinder has an 18" stroke and will do a tad over 70 degrees in one pass. *In the video, the putputput is the cylinder and the backgroung noise is my air compressor trying to keep up.

I used the existing bender mount holes and only had to weld a small "frame" (square arond cylinder) to a metal bolt bushing on the bender. *Two bolts removes the cylinder. *

I'll weld up some legs with wheels for rolling around too.

Only "issue" is that with air/hydraulic (versus powered hydraulic) is that you manually have to push the piston back in.

Kasey

[buildstoys]

The video link:

http://www.youtube.com/watch?v=cTS7h3NkQzE

And the rest of the photos...


Kasey

p.s. Thanks Bug for the HF cylinder link.

[renegadespec1]

Hey that looks great, been thinking of using some air powered rams for my JD2 but haven't been able to get good small amounts of bend out of them... your way looks to be way too easy

[Gene]

Nice work. What is your total investment so far?
Gene

[tenaja]

Looks nice...excellent cost for getting it done. I'd bet you can add a spring to pull it back, but that might slow it down.

Judging from the vid, it's about 1* per second--does that sound about right? Seems kinda slow...how fast was an equivalent bend with the handle? How hard or tiring was it?

Seems like an adjustable auto-stop would be handy, so you could set it up and walk away, and know it stopped where you wanted it to.

[tenaja]

By the way, what's holding the round peg in the square hole? (What's keeping the cyl. from sliding in the square bracket.)

[buildstoys]

Thanks for the kudo's guys.

Total investment (approx) $300 for bender, $215 for die, $80 for air cylinder. *The stand is from a harbor freight solid round bar bender. *Misc scrap metal and nuts bolts used too.

tenaja, as for the cylinder not sliding: the square is snug around the cylinder and the cylinder is cocked slightly against the square. *remember that as the piston expands the whole cylinder pivots on the bolt and thus keeps tension against the cylinder so it won't slide.

yes, it is a tad slow, but my bend in the vid was under pressured. *the specs call for 110psi, I was at 90 and my small 110v husky can't keep a constant.

I could absolutely bend by hand quicker, but it gets old quick: arm starts to hurt and you can't bend and check the degree ring at the same time. *the biggest advantage (other than enjoying a cold one while watching the bender bend on it's own) is that you don't have to mount the bender to anything - portability

it is of course heavy, the cylinder assembly is 36lbs, bender about the same plus stand. *i was thingking of mounting the air pump on the stand too. *you could also mount the whole thing vertically (bender and all) for a slim profile....

all in all, it's cheap, easy to asemble and easy to operate.

by the way, the harbor freight item number for the cylinder is 94562. *they didn't carry it at my local hf store and like i said before, waited a month because it was on backorder


kasey

[tenaja]

Yeah, portability is very nice...nothing like having to unbolt your tools to move them.

The 90psi is typical startup pressure for a cheap pump. You almost have to go industrial to get higher than that. You could use a larger air cylinder, and it'd work at lower pressure, but then you'd have to move more air.

[rowycoracing]

nice job!

[Rorty]

Originally Posted by buildstoys\";p=\&quot

...as for the cylinder not sliding: the square is snug around the cylinder and the cylinder is cocked slightly against the square. *remember that as the piston expands the whole cylinder pivots on the bolt and thus keeps tension against the cylinder so it won't slide.

I understand the principle of angling a slider in a hole - like the trigger mechanism of a caulking gun - but there's a lot of pressure involved there and I've seen the mounting flange on other cylinders break apart during operation, so I can't for the life of me see how the cylinder stays put in the square bracket! Are there no dowels or anything at all connecting the two?