Roll Bar Hoops

[Michael101]

Wondering if anyone has found a source for pre-bent dual roll bar tubing similar to what’s shown in this sketch from TCollins
119717

[Jeff Kleiner]

Send a message to Frank Maslowski ("frankeeski", "i.e.427")

https://thefactoryfiveforum.com/private.php?do=newpm&u=414

I know he has the dies to bend up the radius on roadster bars. He may be able to do these for you.

Jeff

[sethmark]

I can bend them once I get the shop up nd running. Next week or two,

[Michael101]

I can bend them once I get the shop up nd running. Next week or two,

Cool, let me know when you’re set up Seth.

[i.e.427]

Send a message to Frank Maslowski ("frankeeski", "i.e.427")

https://thefactoryfiveforum.com/private.php?do=newpm&u=414

I know he has the dies to bend up the radius on roadster bars. He may be able to do these for you.

Jeff

We've already been in touch Jeff but thanks. Since I lost my machinist, I have no one to turn the roll bar stubs down to the proper diameter. All the local machinist want way to much for piecework/small batches and it's just to cost prohibitive. We can bend the bars all day long but without a way to mount them?

[progmgr1]

I had talked with Frank about roll bars last February and at that time he only had bending dies for 2" tubing. I decided that I wanted 1 1/2" roll bars (used only for headrest supports), so I bought a set from one of the roadster guys on the forum. Now I have to strip the black powder coating and grind off the tubing stub for the rear support - I couldn't figure out a way to keep those and still use the hard top. Eventually, I'll get the roll bars powder coated along with the rest of the chassis. Keith HR#894

[Michael101]

At this point I'm thinking that I want to get my hand on the pre-bent hoops and then figure out my game plan, so I don't know that I need them machined? Looking at the tubing specified on the sketch in the OP it seems that the standard 1.75 tubing may fit into the specified receiver tubes as-is.

[sethmark]

I may be remembering wrong, but I’m pretty sure the factory receivers are 1.5”.

[progmgr1]

The stock Hot Rod roll hoop is 1.5" OD, and the receivers welded to the frame are 1.5" ID (1.75" OD, .12 wall thickness). I plan to weld sections of 1.75" tube to the frame in the correct locations to center the 1.5" OD roadster roll hoops, and maybe add some cross bracing using flat stock. I'm sure you could do something similar with larger size tubing if you decide to go with 1.75" or 2" roll hoops. Keith

[i.e.427]

And that's the other thing guys. I have a 180 degree die for 2" DOM and a 90 degree die for 1-1/2" DOM. A 1-3/4" die ($480) is quite an investment for a roll bar or two.

[sread]

Yeah, it turns out finding somebody that can put a 180 degree bend in 1 3/4 tubing is not easy. I have called several race car and chassis fab shops in the Houston area and haven't found anybody yet.

[JOP33]

Yeah, it turns out finding somebody that can put a 180 degree bend in 1 3/4 tubing is not easy. I have called several race car and chassis fab shops in the Houston area and haven't found anybody yet.

Please reach out to MBB Larry on this site...he may have a local contact.

[sread]

Hey thanks - but I think I have it done now. I dropped off the pieces of tubing at a place called Bendit. It's really more of an industrial type operation but all they do is bend stuff...imagine that. Anyways, the guy said he could do it no problem - hope he gets it right.

[sethmark]

New bender arrived today. I can bend to 180* in a single shot now. If anyone is interested in double hoops I’m going to start mockup shortly.

[DoBoy]

I'd be interested in the double hoops, I'm not really a fan of the single bar.

[FF33rod]

New bender arrived today. I can bend to 180* in a single shot now. If anyone is interested in double hoops I’m going to start mockup shortly.

I've flopped back and forth on whether I want to do this or not. Going to go for it Seth. Thanks! let me know what you need for deposit, I guess once you've completed a mockup and such you''ll have a good guess at price.

Steve

[sethmark]

Let me reset some expectations. If all you want is the hoops bent, I can do that quick. If you want a solution that actually dropped in the car and works with no additional work to speak of, that will take some time.

[DoBoy]

The bent hoops are all I'd need, even better with 2 extra receiver tubes.

[sethmark]

On the right track......

[FF33rod]

PM sent....

Steve

[sethmark]

Can those that are interested play with a tape measure and see if these dimensions make sense?

[progmgr1]

For comparison, the Mk IV 1 1/2" diameter roll hoops that I'm adapting to my Hot Rod are about 11 3/4" center-to-center, 22 1/2" tall (inside) and (very approximately) 17 1/4" tall to the start of the bend. (My hoops are powder coated and it's hard to be sure where the bend starts - so this is an eyeball / feel guesstimate.) (Also, these are tape measure / shaky hand numbers, so add some tolerance for that...) Keith

[sethmark]

That makes sense. Thank you. They’re using a 5 inch CLR die to achieve that radius.

[FF33rod]

I didn't look closely at the height but in terms of the position relative to the center line, they would seem too close together.

By my calculation, the center line of your hoop is 9 7/8 from the center of the cockpit. In contrast, the Tim Collins design has them at 12 3/8

Steve

[j33ptj]

IS that Tim Collins design for the 33?

[sethmark]

No. Bending tube without kinking it requires specific tooling. In my case I have a number of dies, but it’s not the same radius as what he had commissioned. Dies run about $1000 each, so they are pricey to buy for a project that might not yield fruit.