My JD2 Model 32 air over hydro on centerline project

[Jeff 98XJ WI]

I posted this over a period of time on Pirate, but thought those on Naxja would enjoy checking it out as well. I think it’s a pretty neat little project.

I’ve been looking to purchase a tube bender for awhile now and have recently decided to purchase a JD2 Model 32 bender. It’s the only relatively low cost bender and dies rated to bend up to 2” x ¼” tube other than the vertical only Probender pro32. I plan to convert it to air over hydro and mount it to a rolling stand that will allow the unit to be used vertically or horizontally or anywhere in between.

Upon receipt of the bender, I noted that the stationary arms have 1” holes in which the hydraulic ram, that JD2 supplies, mounts and pivots with no bushings. I also noted that a recently purchased Harbor Freight air over hydraulic ram will easily fit between the arms.

I was concerned about the off center mounting method that many of the conversions out there use for the ram and the side loading of the ram that can create under pressure. After searching far and wide I did find ONE guy who did a conversion like what I am planning, but his methods of construction were not fully explained and were somewhat advanced for my skills and available equipment.

http://www.pirate4x4.com/forum/showthread.php?t=998710

Also, he still mounted his ram just a touch off center.

During mockup it looked like I could just fit the Harbor Freight ram in the model 32 bender using mounting pins on centerline with the ram. The ram body would get quite close to the rear most mounting bolt of the bender, but if I clearanced the sleeve on this bolt everything should clear.

I purchased a piece of 3” schedule 40 pipe to use as the clamp around the ram and to mount pins to for fitting into the stationary bender arms. I sliced the pipe along the seam using a cutoff wheel on a grinder and cleaned up the seam using a burr bit in a Harbor Freight electric die grinder. I then cut two pieces of 1” wide by ¼” thick steel to use as clamp flanges. I drilled three holes in these pieces and tapped the three holes in one of them to 5/16”. After slipping the clamp on the ram, I found that a piece of ¼” steel AND a piece of sheet metal just fit in the gap. I removed the clamp, slipped the spacers in the gap, bolted the clamp flanges in position and tack welded them on. I then layed out and drilled two 1” holes in the cylindrical clamp for the pivot pins. I chamfered the inside edges of these holes with the die grinder so I could fill that area with weld later.

I then trial fit the clamp in the bender and clearanced the ram clamp and the rear most bender mounting bolt sleeve to allow the ram body to fit into the bender and swing with the moveable arms without obstruction. Once happy, I made sure a 1” bar I had fit square to the clamp and welded it on. I also finish welded the clamp flanges on. I then used a saws-all to cut the middle of the rod out.

More in next post:

 

[Jeff 98XJ WI]

I used the die grinder and burr to clean up the inside of the pivot pins and then ran a bead of weld from the inside filling the chamfer and connecting the pivot pin to the clamp quite well.

After final cleanup with the die grinder I test fit the whole thing together. The pins fit into the bender arms just fine and the bender can move from completely closed through fully open (as far as the ram will travel) with no clearance issues.

Fully closed

Partially open

Partially open showing the clearance

Open to near where the clearance is at its minimum

Fully extended ram

More in next post:

 

[Jeff 98XJ WI]

Now, the next issue is how to attach the ram to the moveable arms. The ram shaft has a 5/8” hole in it.

The arms have ¾” holes in them and come with ¾” bolts with 1” OD sleeves to go between the arms. The Ram shaft is only 1 3/16” in diameter by the mounting hole which doesn’t leave much material if I tried to drill the mounting hole out to ¾” or 1” or more. I would like to keep the ¾” mounting bolt for strength and I would also like to use bushings on this end since the connection will rotate quite a bit during use unlike the other end of the ram which just rocks back and forth a little bit. I would prefer to keep the factory sleeve and have both bolts tight as well for bender rigidity. So, you can see that I’ve got a problem here. I would like to make a tee style adapter that fits on the end of the ram but there’s not much room for this. In its fully closed position, The JD2 Model 3 has significantly more room to work with as this picture shows.

The Model 32 definitely has less room for fitting the ram with the bender fully closed. Also, the model 32 does need to be fully closed to install 1.5” tube in the die as I found out during testing. I ended up sleeving the JD2 sleeve and then welding a piece of tubing perpendicular to this outer sleeve into which the end of the ram rod fits. I had to cut the ram rod off very close to the ram body when fully retracted for this to work. I used my new JD2 Notchmaster and a 1.5" hole saw. Cut like butter. I purchased two flanged bushings from McMaster Carr 6338K439 SAE 841 Bronze Flanged-Sleeve Bearing, for 1" Shaft Diameter, 1-1/4" OD, 1-1/2" Length which fit over the JD2 sleeve (with just a touch of sanding to the bushing) and slip into 1.5" .120 DOM tubing which I happened to have some of.

Ram fully extended

Closeup of end of ram rod

With moveable bender arms moved beyond ram travel

Fully closed-note how far the ram body had to be cheated back into the clamp. Now I think I need to create a clamp extension to grab more of the ram body! BTW, the bender does need to fully close to fit 1.5" tube into the bender with a 1.5" x 4.5" CLR die set.

More in next post:

 

[Jeff 98XJ WI]

I also purchased two non flanged brass bushings with the intent to install them into the die pivot holes in the arms. I want the main drive pin to easily be installed and removed, the joint to have a bushing for wear, and to keep the arms from falling out when changing dies...especially when mounted vertically. I purchased McMaster Carr 6391K291 SAE 841 Bronze Sleeve Bearings, for 1-1/4" Shaft Diameter, 1-1/2" OD, 1-1/4" Length. I was going to have the holes in the arms opened up a bit for the bushings. There is plenty of beef in the stationary arm.

I am concerned about the amount of material that will be left in the moveable arms though. There looks to be slightly over 5/16" of material now and if I remove 1/8" for the bushing, that only leaves slightly over 3/16".

I am thinking perhaps I should turn the bushings down to around 1/16" wall thickness where they'll press into the moveable arms. This would leave slightly over 1/4" of metal in the moveable arms. It would also weaken the bushing, but it might be just fine.

I bent a piece of 1.5 x .188 this afternoon and everything worked as it should. I did have to repin to get to 90 degrees though. Also, during the test bend I noted that I don't think there is much pressure on the part of the moveable arms I was worried about. It seems to me that all the pressure is on the other side of the hole where there is plenty of steel.

So, I went to my buddies who has a shop with a lot of cool equipment and we drilled out the pivot points on the bender arms with a 1 15/32 twist drill and then reamed them to 1.5" with a ream he had. The bushings were a light press fit into the moveable arms and we filed part of them slightly in a lathe to make a touch looser fit into the stationary arms.

More in next post:

 

[Jeff 98XJ WI]

Also, I needed a spacer of some sort to keep the ram centered between the stationary bender arms, so I drilled some 1" holes in a couple pieces of 1/8" strap, slipped them over the pins and then welded some sides down to the clamp. This arrangement provides the necessary spacer AND provides some additional support for the pins.

I went ahead and welded an extension on the ram clamp. I went from the total thing being 4" long to 7" long.

Now I've got to work on a stand.

 

[old_man]

Nice work.

 

[time2getdirty]

looks like the one I just built for my model 3!
http://www.naxja.org/forum/showpost.php?p=245535044&postcount=4587

 

[Jeff 98XJ WI]

It looks KIND OF like yours, but the big difference comes in the fact that I made the ram push and pull along its centerline as opposed to mounting it to the bender off the side like you and many others have done. With your method, the ram WILL experince side loading. It's not that big of a deal with small diameter thin wall tubing, but when the thing has to work harder with thicker or larger diameter tubing, the side load can damage the ram. The main way one notices a damaged ram is that it becomes harder and harder to retract. Jeff

 

[cracker]

As always Jeff, looking good :thumbup:

 

[Jeff 98XJ WI]

I should have purchased a knob from McMaster Carr for operating the ram release pin when I bought the bushings, but I didn't, so I took a piece of aluminum I had, stuck it in my friends lathe and whipped out this:

It takes a 3/8" (or slightly less) hole to fit over the Harbor Freight pin and then a cross drilled hole for the cross pin and there you go.

I also made a U shaped piece that bolts to the bender. I plan to weld a cylindrical piece to that which will fit inside a second cylindrical piece welded to a stand. Then the whole bender can be rotated from horizontal to vertical to horizontal the other way! I laid out some pieces to sort of get the idea.

I've just got to round up some material and get r done. Jeff

 

[Jeff 98XJ WI]

Here are some pics of the stand welded up. I need to get some casters, but it's together. Horizontal or vertical and adjustable for getting the bender level or getting the tube level prior to bending. Jeff

 

[Jeff 98XJ WI]

Other than paint, I think my stand is finished...although I might add some spots to hold pins and such. I guess we'll see.

Here is the whole thing looking at it from the side with the bender sitting horizontal.

Same config but from above:

Swiveled it vertical without changing anything so the bender arms are plumb.

Here it is sitting in the same position with a piece of tube in it. Notice how the tube is NOT level.

Here I adjusted the swing arm and the tube is now level!

The stand seems a bit big at 3' square, but when sitting horizontal I wanted enough support to prevent it from tipping over. With the casters and sitting level it is 29" to the center of the swivel. The die pivot is 42.25" high in the vertical position with the support arm adjusted down enough to place 1.5" tube level. Jeff