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'72 K5 - Greg's @MightAsWellK5 Build

This is the build description. I will improve this later. (GB)
Overview Gallery Discussion
rdn2blazer said:
I have herd some say hydro is easy to ever bend cause it comes up quick. Or when you only need just a smidge more bend, actually just a flex to get it just right, you can over bend cause you can't just flex it, the bender BENDS it. So I'm still a bit apprehensive about doing it.
Click to expand...

Rob,

I'm sure it's just a "feel" thing....with a hydro valve it's going to be a lot easier than with an electric solenoid (on/off) actuator. That was my concern when I first put this parts list together.... electric is 2 fewer hoses, but there is no "feathering" of the control like there is with a hydro valve. That's why I ended up moving away from an electric solution.

All I need to do is gently crack open the valve and observe...initially there is so little pressure being diverted to the ram that it won't even move it. As I open the valve more, I can build additional pressure and watch the result...if it creeps forward to where I want it, all I have to do is release pressure on the valve and the spring-loaded control automatically returns to center and removes all the pressure. There is no overshoot, unless the operator (me) is being careless or trying to go too quickly.

The only final thing I need to do is get an accurate measurement on springback. This varies based on the type of tubing, bender, etc. So it's not a one-size-fits-all number. And even hydro benders have springback. Fortunately the degreewheel I've got has hash marks before the 0* reference mark, so I can dial-in a few degrees of springback before I even start the bend. That way, I just bend until the pointer shows the correct number, and I know I've got it right once the tube relaxes.

Honestly, I don't think it will be that hard to re-insert a tube and bend a few extra degrees if needed, typically you mark the starting point of the bend and you know the rotation due to the POB bracket, so getting everything back in place shouldn't be that challenging. Trying to UNBEND a tube that's a few degrees too much is another story completely! :D



EDIT: OH YES.....AND WELCOME TO PAGE 5!


:usaflag:
 
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Pic of the toy as it sits with the mods that worked you big doofus...we've all seen tube bent to 180 degrees before. Sheesh! :p:

every bracket that I've tried ends up binding up against the clevis mount at the end of the ram. Basically the ram end is a huge "U" shape, and the bracket ends up being about a 3/4" thick piece of flat stock stuck in the middle of it.
Click to expand...

That big honkin inconvenient clevis unbolts from the ram end...opening up plenty of options that would better have suited you. You got it figured out though, now we just want to see what you came up with!!

Rene
 
tRustyK5 said:
Pic of the toy as it sits with the mods that worked you big doofus...we've all seen tube bent to 180 degrees before. Sheesh! :p:



That big honkin inconvenient clevis unbolts from the ram end...opening up plenty of options that would better have suited you. You got it figured out though, now we just want to see what you came up with!!

Rene
Click to expand...


2009.02.23 - UPDATE! - RENE, HOW ABOUT SOME VIDEO??

Now making his YouTube video debut.......Greg72!! :haha::D:doah:

A quick overview of the bender itself, showing some of the features and stuggles I dealt with...



Video showing a few additional parts I've acquired to get started bending...



The video that shows the actual bending of tube...


The video where the joke is on me... how many degrees are there in 90 anyway?




:usaflag:
 
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3 degrees of pre-compensation + 90 degrees of bend...... and I got 93 degrees total.

All that extra "math" to outsmart the bender, I shoulda just set the needle to 0 and started bending.....it would have been perfect. :doah:


:usaflag:
 
I'm still laughing at the "I need to get some friends" line.:haha:


Come on Greg you should know friends are only good at making fun of you and drinking all your beer.:D











































Can I be your friend? I don't drink beer.....making fun of people on the other hand......
 
3 degrees of pre-compensation + 90 degrees of bend...... and I got 93 degrees total.
Click to expand...

Ah, I was expecting something more than that. So you have 0.3 degrees spring back. I wonder if resetting the pins at 88 degrees affected the spring back rate or can you expect the same amount of spring back at any angle?
 
lookin good Greg!! Looks like about 25 seconds to 90 degrees. I 'think' you took up the springback amount by locking the tube in with the ram. When using it manually it's hard to get the tube that tight in the dies and then set the pointer to zero.

As you said in the vid you have to baseline it somehow, so this is how that is done. Looks real smooth, and a lot less physical exertion than my set-up. ;)

I kinda wonder about the tab off the follower block...that is one difference between the PT 105 and my JD2. The JD2 has no tab and bolt on the follower. I don't get any galling though...:dunno:

Rene
 
tRustyK5 said:
I kinda wonder about the tab off the follower block...that is one difference between the PT 105 and my JD2. The JD2 has no tab and bolt on the follower. I don't get any galling though...:dunno:
Click to expand...

To be honest, this is the first time I've used the tensioning pin on the follower block while bending (oh, THAT'S what those pins with the flat side are for! :p:). When I would do manual bending, there would always be a loud BANG! when I'd release pressure and start trying to get all the drive pins removed. I think the tube might have been wedged backwards against the follower block.

The other thing I had to deal with this time on my newest die set (1.75" dies in the video - BTW) was that there was a lot of galling the first time when I bent the 180* practice part. By machinists standards, I don't think the dies are really THAT well finished as they are received from Pro-Tools. The edges are sharp, and the surface finish is not polished...more like the texture of whatever cutting head was used to create the final shape.

I wrapped some sandpaper around a holesaw and ran it in my electric drill to polish the main die and the follower block to a MUCH smoother finish. I also put a slight radius on all of the sharp edges where the tube transitions into or out of the die to help prevent nicks and defects. The result was a much nicer quality bend with almost no visible scratches on the tube.....I suspect this may be another reason why I didn't get the usual BANG! out of the bender when I unloaded the tube. :dunno:

Anyway, it's all about the little "fine tuning" steps now and learning all the little tricks that will allow me to create highly-precise and repeatable parts.

:usaflag:
 
Greg72 said:
3 degrees of pre-compensation + 90 degrees of bend...... and I got 93 degrees total.

All that extra "math" to outsmart the bender, I shoulda just set the needle to 0 and started bending.....it would have been perfect. :doah:


:usaflag:
Click to expand...

What I found funny was how long it took you to measure this thing, you looked like you were perplexed, kept going back and forth.
By the way, the measurement that you got is a 93 on the tube, when you are measuring the bend on the machine, you are measuring the end of the tube from the straight line, so you need to actually add another 3 degrees to get the 90 on the tube.
What you got now is an 87 degree bend on the machine.
Hope I saved you some time by noticing this now. :rolleyes::D
 
Yeah, if you look closely at that Bosch angle finder you can see that one of the legs is a sort of "U" shape so that it can be collapsed onto the other leg for storage. The problem is that I couldn't get it to sit convincingly against the tube without shifting around, and I wanted to make sure that I was measuring the "flats" beyond the bend area.... you'll notice I finally gave up and grabbed a small scrap of flat stock to use as a backer for that side, and then I was finally able to get both sides fitted up nice and tight for the measurement.

As for your other comment about the degrees....I have no idea what you are telling me there. :dunno: The demonstration piece travelled a total of 93 degrees around the degree ring indicator, and the actual part on the bench came to 93 degrees also.

I'm still puzzled why there is no apparent "springback" in the bender, but the best I can figure it's because as I approach the value on the degree ring and start feathering the controller to hit the number, the springback of the tube is already being bled-out of the part so the pointer is showing what is truly in the part with no stored energy.... :thinking:


:usaflag:
 
Looking good as always. I'm glad to see all of the pain and suffering paid off well.


I do like how fast that bugger is. I have the pro-tools hydraulic ram and kit on mine with a ait/hydraulic pump and it only bends about 40 degrees and 20 seconds per shot. By the time I repin mine 3 times it takes just about 70 seconds to bend a 90.

I agree the finish on the dies is terrible! I used a little flap disk in a die grinder to polish the dies and remove the sharp edges. I also quickly hit the dies before each use to smooth any scratches. It's also improtant to wipe down the tube just before sliding it into the bender to remove any dirt and a shot of lube sure doesn't hurt either.

Are your test pieces DOM? It almost looks like HREW as shiny as they are. Hot rolled has about half the springback as DOM in my experience. It'll take some time to get familiar with all the quirks of the bender, but all the bends come in handy for reference to know how much tube is used in different bends and also to know how much space or distance is used by different bends as well. Of course Bend tec is good at telling you that too. There are those cases when stuff has to be figured out the old fashioned way-chalk on the floor.
 
Yep, it's DOM. I'm used to seeing more of a chocolate brown color with DOM, but I've matched up the markings to the ASTM report and it all checks out. I also wiped it down with Brakeleen before bending it, so it definitely looked purdy and shiny for the camera.

:usaflag:
 
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