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Design help for pipe bending shoes

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
Hello all.

I am building a set of Delrin bending shoes to be used on bright dipped anodized pipe for a hydraulic bender.

I am bending 7" CLR into 1-1/2" 6463 bright dipped anodized SCH 40 pipe.
What I have is a 120 degree Delrin shoe with 1/2" 6061 plate bolted on each side to hold the wall from flattening.
The depth of groove milled for the pipe is just over radius of pipe.

I have two shoes built.
The first is a 9" CLR and is working fine.
The 7" shoe is folding the pipe rather than bending.

So....
Where to go with this to get this done.
The first thing I will do is deepen the groove to get more than radius held on pipe wall with the hope of keeping the pipe from springing out of the shoe.
I am using air over hydraulic and a small compressor so I have to wait for the compressor to catch up as I do the bends.
One thought is the pipe is work hardening and by waiting on the compressor I am not getting this done in one throw so fighting the material.
The other is I am not setting the outboard turning rollers at the correct distance from shoe but have played with close in and further out with same result.

Other thoughts?

Thanks all

What I have :

Screen Shot 2022-03-19 at 5.19.36 PM.jpg
 

Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
My first though is not work hardening, but stress distortion from your stopping and starting. I have a JD2 m52 bender with a 5.5 CL die for 1 1/2. It bends just fine.

My other thought is your pipe is slipping in your die, as the 7" requires a stronger grab to pull it around. This would cause your buckling issue. When you combing slipping with a not consistent single bend, seems like that could be the issue.
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
Pix of bending machine would go a long way here.

Looks to me your not using a Hossfield type bender but rather a simple bottle jack and wheels model like this:
Rigid Only Benders | Greenlee

I could be wrong, so post the pix of said bender
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I am using this type:

Screen Shot 2022-03-20 at 9.55.31 AM.jpg

I am going in to work on it today- I am most suspicious of the depth of groove followed by the start/stop press cycle.
I just picked up a large compressor which I’m installing today so that issue will be gone.
 
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Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
Because of that kind of bender design, you are very limited to how tight you can bend. It will continue to keep bending in the middle because it has no support.

I dont think anything you do will help it honestly.

You will end up having to go to a hossfield or mandrel bender
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
Thanks- I see your point.
But..
There are marine fabrication shops hitting the 90 degree bends in this tube to 7” CLR on these benders.

I got the compressor installed today but didn’t have a chance to to do anything further.
I will see if I can sort this in the morning.
If it’s possible to beat this I will.
 

Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
Is your setup the same as their setup?

Are you bending the same exact material they are? Since galvanized has been chunky plated, it wont sit in the die like bare steel or aluminum would.
 

Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
Also, I was thinking about this today.

If you were to max out that die in a bend, how far away is the 2 idler end rollers? Are they spaced too far for tighter bending dies?
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
Bondo-

Thank you for your input and mulling this over with me.
I got it beat- I upgraded the compressor and adjusted the milling on the Delrin shoe and am getting good 90 degree bend now with the 7" CLR shoe.
I can't say which solved the problem as I did both before trying again but it is good to go now.

Thanks much

The dies are producing perfectly scratch/scuff free bends.
Still a bit of flattening but acceptable.

How round is the tubing coming off of your bender Bondo?

Screen Shot 2022-03-21 at 6.19.11 PM.jpg
 

Bondo

Hot Rolled
Joined
May 14, 2011
Location
Bridgeton NJ
The pipes come out pretty smooth with some die alterations with the runner guide.

I bought it mainly to bend square tube. It does great, bent some 2" 3/16 wall stainless sq tube a whole ago. It didnt like it, but it went fine. 1 bend came out great, 1 bend came out sucked in pretty good.
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
Ok- I brought in a contract for a large superstructure in BD anodized,
To setup for the work I needed upgrades across the board with the custom bender/roller with die sets and rollers plus a new welder etc.
All together a lot of work and money.
This die problem was the last bit to bring it all home and finish the upgrades.
The standard I have to hold is pretty high for the work with clean fab work throughout from the structure design to hold together in offshore service to the bending/fitup and tig welding the anodized pipe.

I’m set now finally- thanks again for the assist.
 

52 Ford

Stainless
Joined
May 20, 2021
Completely off topic, but I like the wood floor in your shop. How well does it hold up? My old boss put knotty pine in his cabin and it looked nice, but it was soft. Dents easily.
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
Completely off topic, but I like the wood floor in your shop. How well does it hold up? My old boss put knotty pine in his cabin and it looked nice, but it was soft. Dents easily.

Remarkably - I have a lot of machinery in a wood framed shop.
I built the shop years ago and as I was putting it together I needed to beef up the single layer of 3/4” T&G ply subfloor.
I was going to double it up and just paint it but at the time that #2 yellow pine was cheaper than another layer of ply so I ran flooring.

I have a LOT of machines stood up in there and do tons of work on that floor.
A couple of decades later-
Great solution.

The shop is easy of the feet to work in and while there is sort of a nice worked on look that hard pine has stood up.
I could use running a sander through the shop and splashing on another coat of poly but won’t.
Also the damn place is like and old farm house with all the additions as I sneak the walls out here and there to get some more room and the pine flooring is always available so easy to get and patch in.

When we first stood the shop up we had a puppy in there and that pup was tossing a big bone around which put a little dent in my new glossy flooring each time it landed.
Whew - I was sweating that as I had just carefully lain sanded and finished the flooring.
Wife looks at me and reminds- “it’s a shop”.

Damn she was right.
All these years later of dropping large things on that floor and I don’t even think twice.

One thing I can say- I was in a restaurant down in North Carolina which was done up with old shop flooring and the whole floor was covered with little swarth curls from a metal lathe pressed into the pine from tooling carts I recon running over the floor.
I don’t get that with the light carts I have and just sweep up the debris from the lathe mills and saws.

And edit- as these things go the pine T&G over ply is a stiffer floor than double ply so I don’t get wallows between joist if a heavy machine pad happens to land there.
All this is relative of course.
My machines are a ton or so each with the heaviest at two ton.
 
Last edited:

Strostkovy

Stainless
Joined
Oct 29, 2017
I use 0.035 or 0.020 urethane die film for bending 1/4" aluminum in press brake dies without marking. It's a bit late now but you might have been able to slip that between a regular die and your tube
 

52 Ford

Stainless
Joined
May 20, 2021
Remarkably - I have a lot of machinery in a wood framed shop.
I built the shop years ago and as I was putting it together I needed to beef up the single layer of 3/4” T&G ply subfloor.
I was going to double it up and just paint it but at the time that #2 yellow pine was cheaper than another layer of ply so I ran flooring.

I have a LOT of machines stood up in there and do tons of work on that floor.
A couple of decades later-
Great solution.

The shop is easy of the feet to work in and while there is sort of a nice worked on look that hard pine has stood up.
I could use running a sander through the shop and splashing on another coat of poly but won’t.
Also the damn place is like and old farm house with all the additions as I sneak the walls out here and there to get some more room and the pine flooring is always available so easy to get and patch in.

When we first stood the shop up we had a puppy in there and that pup was tossing a big bone around which put a little dent in my new glossy flooring each time it landed.
Whew - I was sweating that as I had just carefully lain sanded and finished the flooring.
Wife looks at me and reminds- “it’s a shop”.

Damn she was right.
All these years later of dropping large things on that floor and I don’t even think twice.

One thing I can say- I was in a restaurant down in North Carolina which was done up with old shop flooring and the whole floor was covered with little swarth curls from a metal lathe pressed into the pine from tooling carts I recon running over the floor.
I don’t get that with the light carts I have and just sweep up the debris from the lathe mills and saws.

And edit- as these things go the pine T&G over ply is a stiffer floor than double ply so I don’t get wallows between joist if a heavy machine pad happens to land there.
All this is relative of course.
My machines are a ton or so each with the heaviest at two ton.

I like the look of those old machine shops from the turn of the century - wood floors, line shafts, that sort of thing.

I'm adding onto my shop and decided to keep it all ground level, so I can't do the wood flooring unless I seal the floor under the wood. The lean-to area that my forging stuff is in is right on the edge of a hill, so for me to add onto the back and maintain the same floor level, I'd have to frame the floor and that just adds complexity to the project. I decided it'd be easier to just rent a small excavator and dig the entire addition down 2 feet (which gives me more ceiling height, anyway). Since it's just forging, grinding, and welding in the new area, I'm thinking about doing gravel for the floor. That way, it'll sort of shift around as I walk and won't be as tiring as concrete if I'm standing at the anvil for a couple hours and it'll be easier to keep looking "clean". What I think would be ideal, is to put wood floors in the existing shop space once I move all the welding and forging stuff into the new (and less flammable) area.
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I would say - definitely do not use gravel as a shop floor.
That “shifting around as you walk” will exhaust you if you are pushing long days to get jobs done.

From many many years in shops and job sites I can say without reservation that debris on the floor of any kind is a bad ideal.
Keep shop floors swept and footing certain.
Anything else will tire you out and is dangerous.

Unless you are 20 or so- there are a couple of decades at your disposal where nothing slows you down.
 

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I use 0.035 or 0.020 urethane die film for bending 1/4" aluminum in press brake dies without marking. It's a bit late now but you might have been able to slip that between a regular die and your tube

Given the oddball diameters of BD pipe plus the geometry demands for bending and rolling of the work I have to do I early on abandoned the ideal of shielding commercial dies with film to making custom non marring shoes and dies.
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
I would say - definitely do not use gravel as a shop floor.
That “shifting around as you walk” will exhaust you if you are pushing long days to get jobs done.

From many many years in shops and job sites I can say without reservation that debris on the floor of any kind is a bad ideal.
Keep shop floors swept and footing certain.
Anything else will tire you out and is dangerous.

Unless you are 20 or so- there are a couple of decades at your disposal where nothing slows you down.

You didn't have a smart phone
 

kustomizer

Titanium
Joined
Aug 17, 2007
Location
North Fork Idaho
Years ago I made a bender that made 1" od x 1/8 wall aluminum tube into something like mickey mouse ears. The middle bend wanted to kink sometimes as the ears were being bent, I ended up with a second shoe with a small air cylinder pushing against the opposite side to keep it in place as the rest of the bends happened, that would likely work here as well.
 








 
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