Building a bender

[Damo]

For a while now i've had plans to build a bender. I picked up a 3" double acting hydraulic cylinder and pump a while back for cheap, and after looking at what benders are out there i've decided to make a copy of the Pro-tools one shot.

I have got pretty much everything sorted except for the pin and roller that the follower bar runs on. When bending something this pin is under a hell of a lot of pressure so I want to make sure it's going to be able to handle the pace if you know what I mean. I'm unsure as to what I should make this pin out of. Originally I thought of using something like a 1" high tensile bolt. Can someone help me out? Here is a pic of the one shot bender with the pin in question circled.



Oh, and I know I can buy the pin and roller from Pro-tools. I originally thought I could do it this way but because the hydro cylinder I am using is so big (in diameter) the pin needs to be longer because I have to build the frame bigger to accomodate the cylinder.

Cheers,

Damo.

[bru21]

at least a 16mm high tensile bolt. it is only in shear, the bending should be minimised by the precision fit roller. I can measure the speedwerx which is the same, tonight. mild steel roller will be fine, 60mm or so

cheers bru

[Damo]

at least a 16mm high tensile bolt. it is only in shear, the bending should be minimised by the precision fit roller. I can measure the speedwerx which is the same, tonight. mild steel roller will be fine, 60mm or so

cheers bru

I was thinking about 25mm, the overkill cant hurt right? Well, can only hurt my wallet I spose...

Just trying to work out if I should bush the roller. I was thinking phospher bronze.

[Damo]

I was going to use a high tensile bolt for the pin, but I found some heavy duty pins so I'll prolly use them.

I'll just use mild steel for the roller with a phospher bronze bush pressed in. The bronze isn't too expensive. I'm also going to put a grease nipple in the pin.

Anyone got 250x1000 of 1/2" plate kicking around?

[AJ]

Anyone got 250x1000 of 1/2" plate kicking around?

250x12 is a standard flat bar size.
Try your local steel merchant and see if they will cut a 1000 long piece. (Some will cut, some wont)
Also try local steel fab shops

[Damo]

Anyone got 250x1000 of 1/2" plate kicking around?

250x12 is a standard flat bar size.
Try your local steel merchant and see if they will cut a 1000 long piece. (Some will cut, some wont)
Also try local steel fab shops

Hey, I didn't even think of flat bar!

Reason I said 250x1000 is I can cut that into two 125x1000. So i'll just see if I can get 125 flat bar or close to. Thanks!

Anyone got a 1" drill bit I can borrow?

[Guy]

Anyone got 250x1000 of 1/2" plate kicking around?

250x12 is a standard flat bar size.
Try your local steel merchant and see if they will cut a 1000 long piece. (Some will cut, some wont)
Also try local steel fab shops

Hey, I didn't even think of flat bar!

Reason I said 250x1000 is I can cut that into two 125x1000. So i'll just see if I can get 125 flat bar or close to. Thanks!

Anyone got a 1" drill bit I can borrow?

I would farm that job out .. as you would want the holes in pretty well perfect allignment with as little slop as possible..

Should not be to costly to get an engineering firm to do that one part of it ..

[Damo]

Anyone got 250x1000 of 1/2" plate kicking around?

250x12 is a standard flat bar size.
Try your local steel merchant and see if they will cut a 1000 long piece. (Some will cut, some wont)
Also try local steel fab shops

Hey, I didn't even think of flat bar!

Reason I said 250x1000 is I can cut that into two 125x1000. So i'll just see if I can get 125 flat bar or close to. Thanks!

Anyone got a 1" drill bit I can borrow?

I would farm that job out .. as you would want the holes in pretty well perfect allignment with as little slop as possible..

Should not be to costly to get an engineering firm to do that one part of it ..

I have a drill press that will handle the job, so that's not really a problem. The bit will probably cost more than paying someone to do it though. I'll see how I go.

[Hoonz]

i've got a drill press too

[Damo]

i've got a drill press too

Nice tech jackass if I remember correctly you POS drill press has dodgy wiring and only 1 speed (FAST). It burnt up my 10mm bit, I think a 25mm bit is gonna be toast in seconds now get the fawk outta my thread before I come up there and whoop yo ass

Back on topic... what size hydraulic hose should I be using? 1/4"? 1/2"? 3/4"? I got no fawkin idea but i'm guessin' 1/2" would do it!?!?

Also, I did up a little diagram to try figure out how many hose end connectors I am going to need. Does this diagram look right??? If so that's 7 hoses, & 14 connectors!

[Damo]

Bump!

Cmaaaawn! where are all the hydro gurus?

[spazbot]

1/4 hose will be fine for the hydro, u will need a 3 pos valve block so u have extend tank and retract, do think u need a flow control or pressure relief just run the valves on a momentory switch

[Damo]

u will need a 3 pos valve block so u have extend tank and retract,

Yep, chasing this up at the moment. Cheapest I can do is about $150, the ones I have seen have pressure relief built in.

do think u need a flow control or pressure relief just run the valves on a momentory switch

No, I don't think I need flow control, I was just going to use it coz I had it sitting there. I may ditch it in order to simplify the hoses. Pressure relief on the other hand is more critical AFAIK. From what I understand if the hydraulics gets loaded up too much it can stall out the motor, maybe burn it out. Is that just BS or am I on the right track?

[1MadEngineer]

or maybe?

[Damo]

or maybe?

Do you have a better copy of that, i'm havin a hard time making it out. I have a list of those symbols somewhere, I should be able to decypher it

[Damo]

Here are some pics of the parts I have for the hydraulics side.

This ball valve came with the parts I got. I don't really know what i'd need this for, I haven't counted on needing it.


This is the flow control valve. At this stage I won't be using this because I want to cut down on the amount of hoses. And I don't think I really need it anyway.


This is the pump. I think it's a Rexroth:rolleyes:


Originally I though, OK with all these numbers it should be a piece of piss to figure out the specs. I've been trawling the web and stumbling through the Rexroth web site so far with no luck. If anyone can get me any details that would be great


This is the cylinder. It's a big Mofo.


3" bore, 16" stroke. Dunno what the 1.5" refers to. It's kinda overkill for a bender. I think I will only use about 1/2 the length of the stroke but it's what I have and it was cheap so that's why i'm using it.


Clevis takes 1" pins. Those pins I found at the tractor supply place will be perfect.


I spose 3.5" is about standard for a 3" bore cylinder. The two 1/2" plates for the frame will end up being a little over 3.5" apart, so the 5" long pins will be spot on.


From the measurements I have the 2 plates will end up being about 45" long. So it's not going to be very compact. I might toy with the idea of making it vertical. That should work if I can figure out where to mount the motor, pump & oil tank.

[1MadEngineer]

11cc/rev gear pump, clockwise rot, 5/8" 9tooth splined shaft, sae-A 2 bolt flange.

[Damo]

11cc/rev gear pump, clockwise rot, 5/8" 9tooth splined shaft, sae-A 2 bolt flange.

Thanks Greg

Now I just have to figure out what motor to drive it with. Will 1HP 1440RPM be enough?

[1MadEngineer]

try not to run the system above ~2500psi / 175bar

cc x 1.44 x press(bar) / 600 = power (kw)

11 x 1.44 x 180 / 600 = 4.75kw (~2600psi)

3" bore @ 2600psi = 8ton (stuff all)

the problem is that most cylinders in jack are able to operate upto 6000+ psi and the small hand pumps will sometimes be able to put out upto 10000psi. most ag/commercial cylinders and seals are barely good for 4500psi. gear pumps arent that reliable above 3500 either.

so a 5.5kw / 7.5hp motor is the go!
and 10-14amp 3phase DOL.




enjoy!!!!!!!!!!!!!!!!!11

[Damo]

try not to run the system above ~2500psi / 175bar

cc x 1.44 x press(bar) / 600 = power (kw)

11 x 1.44 x 180 / 600 = 4.75kw (~2600psi)

3" bore @ 2600psi = 8ton (stuff all)

the problem is that most cylinders in jack are able to operate upto 6000+ psi and the small hand pumps will sometimes be able to put out upto 10000psi. most ag/commercial cylinders and seals are barely good for 4500psi. gear pumps arent that reliable above 3500 either.

so a 5.5kw / 7.5hp motor is the go!
and 10-14amp 3phase DOL.




enjoy!!!!!!!!!!!!!!!!!11

That is a big mother of a motor. I'm only bending tube, cant see it needing to do more than 3mm wall 2" tube. Do I really need that much power?

[Webbie]

hows the bender coming along DAMO

[Damo]

hows the bender coming along DAMO

Been getting flogged at work lately so time has been a factor. I have chased up another pump though (this one's around 3cc/rev), so i'll prolly put the one I have on flea-bay.

[AndrewPatrol]

If you build it verticle wouldn't that make it hard to position the tube, to get the bend in the right place, without hitting the floor?

[Damo]

If you build it verticle wouldn't that make it hard to position the tube, to get the bend in the right place, without hitting the floor?

I thought the best description of mine was horizontal, not vertical, so i'm not sure if you have the right idea. Have a look at the pic at the top of this page, picture that sitting on top of a saw horse, that's the basic idea.

When it bends the tube will actually swing in the horizontal plane, not the vertical plane. This does cause a problem if you want to do a 180 degree bend as the tube will swing around and hit the bender. You would get prolly 110 - 120 degrees max out of it i'd say.

For the record, the vertical benders I have seen (eg. Speedwerx) bend so that the tube swings upwards rather than towards the floor.

[runnin4life]

im not sure if the bender we have at work is the same system as yours it looks similiar system it has 2 dieso n the bottem and on on the top which goes up and down and the other dies swing up and out


i think its called a centre line bender piss easy to use but it has a control panel where u dial in the degree and the size of the pipe and put on the dies for that pipe and away you go

but ill be fuked if i can work all the maths out for it lol

althought it probally doesnt help in any way i hope it does

cheers
elliot

[Roctoy]

hey Damo!
How is this thing coming along?

Chris

[Damo]

hey Damo!
How is this thing coming along?

Chris

Not so great. Time's been an issue, I haven't even been on this forum for ages. Should have my shed finished soon though, that'll help. As for the bender, i'm probably going to end up getting a JD2.