My Edge Bender

For discussions related to designing and making ski/snowboard-building equipment, such as presses, core profilers, edge benders, etc.

Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp

twizzstyle
Posts: 2204
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

My Edge Bender

Post by twizzstyle »

I need to give all credit here to the Skevik guys. I saw their edge bender in their awesome video and thought it was ingenius, so I wanted to make my own. What I made is essentially identical to theirs, with just some minor improvements for a more "finished" look.

Here is the Skevik guys' thread for reference...

http://www.skibuilders.com/phpBB2/viewtopic.php?t=2016

Here is a rundown of all the parts I used...

- Harbor Freight 4" drill press vice $15
http://www.harborfreight.com/cpi/ctaf/d ... mber=30999
- Two rubber knobs with 1/4-20 threaded insert from McMaster-Carr
http://www.mcmaster.com/#6185k36/=4e7pst
- One rubber knob with 1/2-13 threaded insert from McMaster-Carr
http://www.mcmaster.com/#6185k47/=4e7plk
- 3 rollers machined by a local for $100 (most machine shops wanted $200-$250 to make these)
- Various bolts/washers and some scrap steel rod

First I did a little work on the vice. It had some crappy green paint that was chipping off, so I stripped all of the paint off and repainted it with black wrinkle finish. I drilled and tapped the vice with 1/4-20 holes for the bolts for the rollers.

I didn't like the floppy handle thing for opening/closing the vice, so I welded it so it was straight with the threaded rod, then used a die to cut threads onto the end of it to accept the rubber knob. This is much nicer on the hands when you're moving it in/out.

The other two knobs went on the handle crank thing, they are attached with 1/4-20 bolts just tight enough so there is no play in them, but they spin freely.

When I did some test bending, I found that once there was a lot of force on the movable jaw, it would tilt backwards since there is no guide rod. My solution was to weld in a 3/8" steel rod underneath, with a guide that slides over that that I then welded to the movable jaw. Now there is NO play in any direction, but it still slides easily forward/back. HUGE improvement to the crap $15 vice. This made it so I couldn't get to the set screw on the bottom that holds the jaw to the threaded rod, so I had to drill/tap a hole on the top to accept a new set screw.

The biggest expense was the rollers... I am determined to buy myself a nice metal lathe now, its a tool I've always wanted, and I would have much rather made these myself anyways. If anybody wants to make one of these themselves, here are the drawings I came up with for the rollers. Any good machinist should be able to turn these for you, but it'll cost you...

Image

Image

The tool works great, it doesn't always feed the edge through on its own but if you pull or push with your other hand while you turn the crank it goes right on through. Super easy to make fine adjustments to the radius of bend. I'm not even bothering to flame heat the edges before bending like I did when I bent by hand, I'm doing cold bends.
twizzstyle
Posts: 2204
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

Post by twizzstyle »

Pictures of the bender...

Image

Image

Image

Image

Image

Image
nick
Posts: 91
Joined: Mon Jul 20, 2009 1:57 pm
Contact:

Post by nick »

sweet! Man it sucks that the most expensive part are making those wheels. Thats expensive. Very cool though.
sammer
Posts: 933
Joined: Wed Dec 19, 2007 10:37 pm
Location: Fernie B.C.
Contact:

Post by sammer »

Awesome, thanks for this twizzstyle.

Now to find a machine shop. I'm pretty sure the old guy up the street has a lathe :D

sam
You don't even have a legit signature, nothing to reveal who you are and what you do...

Best of luck to you. (uneva)
User avatar
Head Monkey
Posts: 310
Joined: Sun Jul 17, 2005 4:53 pm
Location: Carnation, WA
Contact:

Post by Head Monkey »

Very nice work!
Everything I know about snowboard building, almost: MonkeyWiki, a guide to snowboard construction
Free open source ski and snowboard CADCAM: MonkeyCAM, snoCAD-X
webboy
Posts: 108
Joined: Mon Oct 12, 2009 4:14 am
Location: Sweden

Post by webboy »

That seriously rocks! Thanks so much for sharing, especially the drawing.
User avatar
nrgboards
Posts: 69
Joined: Wed Nov 04, 2009 5:38 pm

My Edge Bender

Post by nrgboards »

What if you use washers of various sizes to build those rollers?
User avatar
chrismp
Posts: 1443
Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Re: My Edge Bender

Post by chrismp »

nrgboards wrote:What if you use washers of various sizes to build those rollers?
i think someone already did that...so it should work fine.
skidesmond
Posts: 2337
Joined: Tue Apr 07, 2009 3:26 pm
Location: Western Mass, USA
Contact:

Re: My Edge Bender

Post by skidesmond »

nrgboards wrote:What if you use washers of various sizes to build those rollers?
Washers will work. After I saw Skeviks' video w/ the edge bender I had to have one. I have been using an tube bender ($15). I cut a small groove in it to hold the edge but it was still awkward to use and the steel edges tend to twist and the teeth tend to bend out of alignment. Seemed like I needed a third hand to work it.

The Skeviks edge bender looked straight forward to make but knew I couldn't find the rolled steel bars easily. So for the hell of it I bought 3 - 1/2 x 2.5 inch bolts, 12 washers with 1 3/4in dia, 3 washers with 1 3/8 in dia. 6 - 1/2in nuts. I sandwiched the smaller washer in between 4 larger washers. Here's a pic of the how I assembled the hardware.

Image


To see how or if it would bend I clamped 2 of the assembled bolts into my vise. Inserted a steel edge and it worked pretty good. No twisting occurred and the teeth stayed in alignment.

Image

Image

Image

Cost of parts was less than $3.00. I'm going to work it into a bender like Skeviks.

Even a simple bender like the pic above made bending edges so much easier than the modified hand bender.

Twizzstyle - excellent schematic!! You made everyones life much easier.
twizzstyle
Posts: 2204
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

Post by twizzstyle »

Nice work with the washers!

It's pretty hard to justify the ~$130 cost of mine (total cost including all parts) over $3 for some bolts/washers :(

One cool thing about mine though, it would take very little work to replace the radius adjusting knob with a stepper motor, and turn it into a CNC edge bender 8) Maybe that'll be a project for next year, for now I need to hurry up and get some skis made, the snow's already falling!

Something like this would be the result...

http://signalsnowboards.com/EDGES
skidesmond
Posts: 2337
Joined: Tue Apr 07, 2009 3:26 pm
Location: Western Mass, USA
Contact:

Post by skidesmond »

Thanks. Yeah, mine is definetly low budget/low tech and I surprised myself that it worked. I forgot to mention that one of the smaller washers is a bit thinner than the other 2 small washers. I used the thinner one for the teeth and used the thicker washer for the edge, which made for a good fit. With the washers you need to make sure they are aligned properly and bolted very tight so nothing moves when you start bending.

Now that I think of it I do know someone who is a machinist. Might have to ask for a favor.... ;) But for the time being I'll have to stick w/ the low budget option.

I'm going to pick up a vise like the one you have at TSC (Tractor Sppply Co.) so I can have a dedicated edge bender. Thanks again for the drawings, it will make it much easier to make.

No snow here yet (Mass). But I do have a pair of skis in the press right now. This will be my second attempt. Probably leave them in the press over night.... it's getting late.
User avatar
threeninethree
Posts: 172
Joined: Fri Feb 23, 2007 8:11 pm
Location: Massachusetts

Post by threeninethree »

Twizzstyle,
How is the main roller attached to the jaw that enables it to spin freely?
If you dont mind me asking?
~ Matt
twizzstyle
Posts: 2204
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

Post by twizzstyle »

threeninethree wrote:Twizzstyle,
How is the main roller attached to the jaw that enables it to spin freely?
If you dont mind me asking?
All of the rollers spin freely. They have a 1/4" hole drilled in the center, and then a 1/4-20 bolt going into holes I drilled/tapped in the jaws of the vice.

I have the bolts JUST tight enough so that there is no up/down play in the roller, but it still spins freely (there are washers top and bottom as well). I also put red loctite on the bolts, so they won't wiggle themselves loose.

Then the arm to turn the main roller has two bolts going into the roller, but they don't go all the way through the roller and into the jaw, since it wouldn't spin then :)
hafte
Posts: 204
Joined: Wed Jan 11, 2006 11:40 am

Post by hafte »

Twizzstyle, I’m working with one of the machinists here at work who has a lathe at home. He can make the parts for me, but has me wondering about some of the tolerances in your drawing. Is the .025 for the teeth to run in that tight so the tool has traction on the edge so it feeds through the rollers properly or is it that not so critical (kind of sounds like it). The edge piece I gave him to work with has teeth that are averaging .024 in thickness.

His other concern is the depth of cut for the teeth. It’s a tough to find a tool that thin that will cut that deep, so he’s going to make it in two pieces. That way he can thread the handle holes in the bottom part and I can use the handle bolts to hold it all together.

Skidesmond, How’s the washer bender doing. I may opt for that. A few $$ for washers is much better on the pocket book.

Thanks for the drawings and ideas guys. Beats the heck out of the heavy leather gloves and muscle that I have been using.

Hafte
twizzstyle
Posts: 2204
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

Post by twizzstyle »

Ok, so the .025" groove is just to help keep the edge from curving the wrong way, it keeps it flat after bending. I think my grooves ended up being a little wider so thats ok, but you don't want to go too wide.

A few machinists recommended to me doing it in two pieces as well, and bolting the two together, I think thats an excellent way to do it, although the guy I finally went with did it in one piece.

You can get slitting saws at .025", but you need a mill with a turntable to do that accurately.

As far as I know my rollers were all done on a lathe, no slitting saw, so they were able to make a tool narrow enough... but again, I'm not sure how much wider than the .025" it ended up being.

When it really comes down to it, you want the edge to go in there easily, without having any slop, thats all that really matters. Give the machines a short section of edge and say "make this fit with no wiggle room" :)
Post Reply