how do I get/make rollers for weld coupon test bender

[opa]

Hi All.

I plan on building a weld coupon bend tester, similar to the attached diagrams and photos. how can I get or make the rollers?

1. Can I buy the two rollers “off the shelf”? (this would be easiest approach i think). i cannot locate a seller. i think they should be hard steel. They need to be at least 1.75 inches long (since the coupon width will be 1.5 inches. Can you tell me where I can buy these? Roller diameter should be 1.5 inches, or more. I searched for a seller without success.

2. If these rollers cannot be purchased, how would you make them? I am thinking 4030 steel tube cut to 1.75 inch length. I do not have a lathe or way to machine them. do i buy a bushing that goes between the steel tube and a bolt? would it need to be a tight fit? or would a loose fit be okay? where to buy bushings? what type? solid brass? or should i use needle bearings inside a tube? i have never done bearings before.

i know i could weld in some fixed non-rotating “rollers” on the shoulders of my fixture (such as wrist pins, or solid rod), but i prefer to utilize rollers that will actually rotate.

i am hoping you can help me find where i can purchase rollers, or how to make rollers. any ideas or advice would be appreciated. thanks.

[Shootr]

No idea if this will help, but for my work (conveyor repair-commercial) Omni Metalcraft makes our rollers and pulleys.

https://omni.com/products/conveyor-rollers/

They custom make just about anything we come up with. Wall thickness, diameter, length, axle size, bearing type, etc.

If a roller won't work, possibly one of their pulleys.

[123weld]

[QUOTE

1. Can I buy the two rollers “off the shelf”? (this would be easiest approach i think). i cannot locate a seller. i think they should be hard steel. They need to be at least 1.75 inches long (since the coupon width will be 1.5 inches. Can you tell me where I can buy these? Roller diameter should be 1.5 inches, or more.thanks.[/QUOTE]

some dom tube w/ a bolt for shaft. i got some dom thats perfect for that. its ur 1.5"od, its got a .237 or .243 wall or something like that, so its got a lil clearance for a 1" bolt w/ a dab of grease on it. i got some 1.5" in .250 wall also, so if bolt shank is a couple thou under, it might be good too. u dont need hardened, buy a couple feet of dom, and ur set for life. " hangtown", yea

[opa]

123weld:

"some dom tube w/ a bolt for shaft. i got some dom thats perfect for that. its ur 1.5"od, its got a .237 or .243 wall or something like that, so its got a lil clearance for a 1" bolt w/ a dab of grease on it. i got some 1.5" in .250 wall also, so if bolt shank is a couple thou under, it might be good too. u dont need hardened, buy a couple feet of dom, and ur set for life. " hangtown", yea"


sounds like your 1.5 outer diameter tube with .243 wall would work good. (to show my ignorance, if i got your 1.5 tube with .250 wall, i don't know if 1" bolts are sold at under 1" or only at exactly 1"). let me check with McMaster carr on what diameter their 1" bolts have, and i will get back to you. i am definitely interested in your suggestions, and appreciate your feedback.

[Welder Dave]

Pretty much anything should work, just need the rounded corners. If your welds are good they won't crack or break. Tech school had a press in every lab. They pushed the coupons right through with a bit of a bang when they popped through.

[danielplace]

123weld:

"some dom tube w/ a bolt for shaft. i got some dom thats perfect for that. its ur 1.5"od, its got a .237 or .243 wall or something like that, so its got a lil clearance for a 1" bolt w/ a dab of grease on it. i got some 1.5" in .250 wall also, so if bolt shank is a couple thou under, it might be good too. u dont need hardened, buy a couple feet of dom, and ur set for life. " hangtown", yea"


sounds like your 1.5 outer diameter tube with .243 wall would work good. (to show my ignorance, if i got your 1.5 tube with .250 wall, i don't know if 1" bolts are sold at under 1" or only at exactly 1"). let me check with McMaster carr on what diameter their 1" bolts have, and i will get back to you. i am definitely interested in your suggestions, and appreciate your feedback.

Bolts solid unthreaded portion is under nominal size. A 1/4"(.250") bolt is .240" a 3/8"(.375) bolt is .360 so I would expect at a 1" size it would be a bit undersize like .960"

Evidently that must not be true of them all. This chart list the shank diameters at larger than bolts nominal size. Odd because I just measured 20 bolts from all different manufacturers and all were smaller shank than bolt size. Be stupid to have a 1" hole and buy a 1" bolt and it be too big for hole. 1/4" bolt fit in 1/4" holes usually as do 3/8" so chart below seems whack.

http://www.badensteel.com/bolt-dimensions

"A" was the unthreaded shank diameter.



Would it be too expensive to buy some large ball bearings and stack them on each shaft to make the rollers.

3/4" I.D. https://bearingsdirect.com/ball-bear...-8x7-16-sealed

10 of these are only $40

1" I.D. https://bearingsdirect.com/ball-bear...g&results=3895

[VaughnT]

A very nice How-To from the fine folks over at Weld.com crew.

[VaughnT]

A very nice How-To from the fine folks over at Weld.com crew.

[tapwelder]

Hf pipe bender would be easily modifiable. Only need an upper die.

[Country Metals]

The ornamental bender at HF has multiple sizes of the rollers you need. I know 7 ish years ago they were at least case hardened

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[opa]

OP here. i have questions i need help on. i built a bend tester fixture, and i built a plunger that will press down on my welding coupons so i can bend test them.

attached are two photos. they will be used with a hydraulic press.

I used 4140 for the plunger. it came from McMaster carr and is annealed (i believe it presently has a rockwell c hardness of RHC 10). I welded the 4140 to a bar of 1018 mild steel (i used 312 tig rod). I will mount the plunger on my hydraulic press. but before i install it:

questions:

1. should i use the 4140 plunger "as is"?

2. should i first heat treat the 4140 plunger (heat to austenitize and then quench ( in oil? in water?) and then temper it ?

3. should i "case harden" the 4140 plunger with Cherry Red "instant hardening compound" powder instead of heat treating it ?

i have never heat treated or case hardened steel before.

my thoughts: the plunger is probably hard enough "as is" since it already has chrome-moly and .40 % carbon. but i would like to see what you all think. thanks for your feedback.

[Country Metals]

If you aren't testing a lot of items, plain cold rolled 1018 or so is just fine. So you will be ok.

If your a weld testing school, a tool steel would be best as you would want to wear out your tester on someone else's coupon.

Maybe change your bolts to grade 8 or 12 depending on thickness, bug I would have made the bolts at least 3/4"

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[smithdoor]

It simple with little machinist back ground.
I would look at bolts it simple and can done with out a lathe.

Dave

Hi All.

I plan on building a weld coupon bend tester, similar to the attached diagrams and photos. how can I get or make the rollers?

1. Can I buy the two rollers “off the shelf”? (this would be easiest approach i think). i cannot locate a seller. i think they should be hard steel. They need to be at least 1.75 inches long (since the coupon width will be 1.5 inches. Can you tell me where I can buy these? Roller diameter should be 1.5 inches, or more. I searched for a seller without success.

2. If these rollers cannot be purchased, how would you make them? I am thinking 4030 steel tube cut to 1.75 inch length. I do not have a lathe or way to machine them. do i buy a bushing that goes between the steel tube and a bolt? would it need to be a tight fit? or would a loose fit be okay? where to buy bushings? what type? solid brass? or should i use needle bearings inside a tube? i have never done bearings before.

i know i could weld in some fixed non-rotating “rollers” on the shoulders of my fixture (such as wrist pins, or solid rod), but i prefer to utilize rollers that will actually rotate.

i am hoping you can help me find where i can purchase rollers, or how to make rollers. any ideas or advice would be appreciated. thanks.

[cwby]

Just stack however many bearings you need to make width on a bolt. Find a bearing with correct outside diameter, say it is 1/2" thick, you need 4 of them on the bolt to make a 2" roller...