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-   -   Mandrel bender project (https://www.rx7club.com/rotary-car-performance-77/mandrel-bender-project-242784/)

Scalliwag 11-18-03 05:55 AM

Damn Coldy you have that lathe just sitting there? ARGH!!! I would not be able to sleep at night until that was up and running :eek: Is it single or 3 phase?
If it is single just get the heaviest gauge Romex you can find and tap into your box. If it's 3 phase then get a phase convertor.

With the weight of the dies the shipping would be pretty high. Anything outside Dallas/Ft.Worth would probably not be very practical. The way it breaks down in exact numbers on my dies was $73 on the steel, $30 on the bearings (which I have found for less now) and $250 per set for machining. I have bearings for the arms as well so my price breakdown on my 5th post was not redundant when I quoted $400 on the dies and then mentioned bearings again with misc. materials.
So I was about $50 high after going off receipts.
So $125 to cut one of the dies is not too bad. Of course it is the single highest cost other than a *good* hydraulic system that will come later on.

I am not sure if you guys noticed but I used tapered bearings for the dies. I have flange bearings for the *final* arms. The reason I used taped bearings on the dies was for load support and it makes them easier to get on and off.
Another really good unplanned blessing with that is now I only have to buy bearing "cups" for a couple bucks each instead of the complete bearings for the rest of the dies.
Since they are not worked at high speed I am not using grease because it would be a mess. Instead I sprayed the entire dies with graphite to mainly keep the rust down and to dry lube the bearings.
So in case you wondered why the dies went from being real shiney to gray that is not paint.
Hopefully I can get the thick flat bar at lunch today. As a matter of fact I need to go take some measurements.

pinkfloyd 11-18-03 11:22 AM

how did you spray graphite. the only way i know of gettign graphite is in that little tube that i use for my co2 powered cars, for the wheels

Scalliwag 11-18-03 11:48 AM

Well you will like this shit then ;) I get it in both the aerosol and the bucket. But now that I have found the re-fillable aerosol cans at Harbor Freight I am only buying the bucket. You can dilute it with either mineral spirits or acetone (I can't remember which, it says on the bucket) so you can take some of the thick shit from the bucket and put it in the re-fillable aerosol, pour in some solvent and shake the shit out of it, screw the top on and hit it with some air and WALA!!! you have a "Scalliwag do-it yourself kit" ;) I figure you can make 748 cans per bucket :) Honestly there really is no telling how many times you could do that. The stuff in the bucket is unbelievably concentrated.

I need to make a thread on doing that and making an aerosol rubberizing compound the same way. You guys will like those little tricks.
See my thread on fixing the nasty door trim rust problem on second gens for the rubberizing idea.

Scalliwag 11-18-03 12:02 PM

Damn all that yakking and I forgot to post the link :confused:

http://www.mytscstore.com/detail.asp...productID=2296

pinkfloyd 11-18-03 01:02 PM

sweet thanks.

xbootyguyx 11-18-03 04:06 PM

What are you going to use for the Mandrel in side the tubeing?

Scalliwag 11-18-03 04:40 PM


Originally posted by xbootyguyx
What are you going to use for the Mandrel in side the tubeing?
You don't need anything on the inside. In order for the tube to collapse on one side it has to expand somewhere else. If the dies do not allow the pipe to expand it forces the pipe to maintain to the shape of the dies.
Or at least that's what the hell better happen or I'm goin' apeshit!!! ;)

xbootyguyx 11-18-03 05:05 PM

Your going to still need to pack the tube with sand to act as a Mandrel or you will crush it.

Scalliwag 11-18-03 05:14 PM

I ain't skeered!!!! At least I do have some sand but I hope I don't have to use it. If I do I will use some rubber plugs setup like a rubber freeze plug.
Good or bad I will post results so you guys can give me the "told you so!!!!" treatment :D

pinkfloyd 11-18-03 06:00 PM

lets just say if it dose crush with this setup(i hope it dose not) i dont think sand sould stop it. the sand would have to be packed so tight to work. I dont know much about this, what else is used as a mandrel, like on real mandrel benders. i have looked on google to find out more about these to learn more but did not come up with much.

Scalliwag 11-19-03 12:41 AM

I picked up the flat bar and made the mounting for the extra support at the top side. Then Brian Cain (BDC)dropped by and we ran over to Gotham Racing (a mile and a half from me! :) ) and I just got home so no more worky on it tonight.
Tomorrow I make the braces. I should be ready to crush, I mean bend a pipe tomorrow evening. Unless someone else comes and kidnaps me again :(

enzo250 11-19-03 08:53 AM

Hey Scalli.

What do you plan on bending? Alum?
I own a mandrel bender so i know a few things about them. Anyhow your gonna need a mandrel(hence the name mandrel bender) inside the tube you plan on bending otherwise you will never have a true mandrel bent tube. They will come out egg shaped.

enzo250 11-19-03 08:57 AM

BTW.

heres a pic of my machine...

Scalliwag 11-19-03 09:20 AM

What does the mandrel that does inside it look like? I thought the dies were mandrels?

banzaitoyota 11-19-03 09:31 AM

looks like an egg
look here, it resembles a marital aid!!!

http://www.ercolina-usa.com/mandrel-bender-specs.htm :D

Scalliwag 11-19-03 09:56 AM

Damn with that no woman would ever need us!

http://www.ercolina-usa.com/images/m...s/mandrelt.jpg

Cool info that I definately need. From what I am seeing I can see why you referred to that as a chaser before.
It looks like you put it into the tube to a specific point where the dies start the bend and you have to attach whatever rod the it attaches to to a fixed point.
In my case I will need to extend a length of pipe off the end of the pipe rest that has to be longer than the tube I am bending. Then have a little arm or something come up behind the end of the tube so the "chaser rod" can attach to it and hold the shlong at the correct point.

Does that sound logical?

Rx7carl 11-19-03 10:02 AM

Hloy cow! Thats a bender! :eek:

Oh and Dow Corning makes an aerosol graphite spray. Comes in a can. We use it in avation as a dry lubricant.

Scalliwag 11-19-03 10:43 AM


Originally posted by Rx7carl

Oh and Dow Corning makes an aerosol graphite spray. Comes in a can. We use it in avation as a dry lubricant.

What's really funny is I bet that the aerosol graphite the Tractor Supply sells to farmers for $5 a can is the same stuff as gets sold to the aviation industry for probably $20 a can.
If that's the case Carl then we need to buy a shitload of the Tractor Supply graphite and make some fancy labelling and sell it to them for $15 per can ;)

Scalliwag 11-19-03 10:52 AM

Hmmm, I got to looking at something. I would have to make my pipe get pulled into the dies for this to work. So I will have to make a locking mechanism on the stationary dies. This may change several things actually.
Well at least I figured there would be some changes on the way :eek:

Rx7carl 11-19-03 12:17 PM


Originally posted by Scalliwag
What's really funny is I bet that the aerosol graphite the Tractor Supply sells to farmers for $5 a can is the same stuff as gets sold to the aviation industry for probably $20 a can.
If that's the case Carl then we need to buy a shitload of the Tractor Supply graphite and make some fancy labelling and sell it to them for $15 per can ;)

Correction. I was thinking of M02s. I do recall some graphite spray we used, but cant remember the mfg. Might have been Dow. LOL, we prolly pay $100 a can. Just like racing. To make a small fortune in avation, start with a large one.

pinkfloyd 11-21-03 11:22 AM

i want more info,more pics,more more more. hehehehe. i just cant wait any longer.

Scalliwag 11-21-03 11:35 AM

I can take a couple of pics of a bend the really went awry :(
I went ahead and tried to bend it in the current configuration and damn I did not know a pipe could be made to look like that in anything other than a car wreck :eek:
I have to do some major changes to this. It will be real interesting. This will be a very busy weekend for sure.
Thanks to the info that several of you gave me I have a few ideas to try next. The main change is making the tube get pulled into the mandrels.
But yeah, that first bend was a real mess. I took a night off from it last night for my "boys night out" at the club.
I should be over the hangover by this evening and get started back at it.
Oh, and quit laughing about the fugged up bend! ;)

scathcart 11-21-03 12:17 PM

Lets see this :D

Scalliwag 11-21-03 12:37 PM

It's pretty sad (at least to me :( ) It looks like something from the Hindenberg :eek: But Enzo was wrong about it coming out looking like an egg. An egg would have been an improvement. This is shaped more like a chicken than an egg..... hmmm, maybe the chicken did come before the egg :confused:

coldy13 11-21-03 02:40 PM

I can take a picture of a bender we have in my schools shop. I think it can't bend more than 2" pipe, but it makes nice bends. It seems similar to yours, except it uses a long arm that you have to push instead of a hydraulic ram. Maybe it could give you more ideas on how to make yours work right.


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