OK,
So we built the press, made a custom heating system with temperature controller, I pursueded CAMAX to do a run of M5 inserts, crafted six sets of beautiful cores with ABS edges attached, ordered all the fibreglass and resin and it was all going sooooo smoothly until...
... I tried to bend the edges. Try as I might I cannot bend my edges to map close enough to the base that they will stick in place with the glue. I seem to have 3 key problems:
1) Just getting the bend to the right curvature is tough
2) Getting the bends in the right place (tip OK and tail OK but they are too far apart or too close)
3) Bend goes 3d (in the tight bends I find that my edges are not bending 'inline' but are bowing down at the edges and up towards the centre of the ski)
Some Backround:
1) I am using an edge bender like that illustrated by the Kams
2) I have not annealed the steel (this is probably my mistake, but I am using a coated edge and ideally I should not heat it)
FWIW I consider myself normally to be pretty good at crafting things (engineer, done a load of home tinkering etc...) so this hurts my ego that I cannot do it! So what is my problem? Does the annealing make that much difference? How do you position your bends accurately?
Go on tell me your secrets and I will buy you a beer!
Yours, frustrated,
B.
Edge bending - Arrrggghhh!
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
I use the same bender as noted and was luck to find a metal wheel with two radiuses. I can flip it over to use the other radius for tighter bends. I have not annealed the metal, but may try to get a full wrap at the very tip, but there is discussion that it may not be the strongest tip configuration.
Here is how I have been doing mine.
Clamp the ski pattern to the edge of a table with a welders vise grip type clamp so that the entire edge of the pattern hangs off the table. A c-clamp would work too. Anything that will give you clearance to lay\remove the edge along the pattern while keeping the pattern clamped down.
Be sure the pattern is marked with the ends of the effective edge and at least a CC or center mark.
Put the edge on the pattern and clamp it with spring clamps to hold it in place. It will take three or four to hold it in place. Mark the ends of the effective edge on the metal edges with a sharpie. I also mark the CC and anything else that will help keep the alignment good.
Take the edge off of the pattern. Put an end in the bender and start bending at the mark. Pull it off the bender and check it. Keep working your way around as far as you want to go around the tip of the pattern. Make additional marks with the sharpie as you match the curve so you know which parts of the curve match and don’t bend it there again. Cut to length after the edge is bent.
My patterns are made 4.4 mm narrower than the finished ski so the teeth on the edges are on top of the pattern which is the same size as the base material.
This has been some of the hardest work to get right for me too. Take your time check the bends often. Do little bits at a time. The tight bends would cause the teeth to bend up, so I had to bend them back straight and flat by hand. The metal is very hard and springy so over bending was required.
Hope that helps. I hope to get a digi camera soon and I’ll try to get pictures and a real journal going.
Hafte
Here is how I have been doing mine.
Clamp the ski pattern to the edge of a table with a welders vise grip type clamp so that the entire edge of the pattern hangs off the table. A c-clamp would work too. Anything that will give you clearance to lay\remove the edge along the pattern while keeping the pattern clamped down.
Be sure the pattern is marked with the ends of the effective edge and at least a CC or center mark.
Put the edge on the pattern and clamp it with spring clamps to hold it in place. It will take three or four to hold it in place. Mark the ends of the effective edge on the metal edges with a sharpie. I also mark the CC and anything else that will help keep the alignment good.
Take the edge off of the pattern. Put an end in the bender and start bending at the mark. Pull it off the bender and check it. Keep working your way around as far as you want to go around the tip of the pattern. Make additional marks with the sharpie as you match the curve so you know which parts of the curve match and don’t bend it there again. Cut to length after the edge is bent.
My patterns are made 4.4 mm narrower than the finished ski so the teeth on the edges are on top of the pattern which is the same size as the base material.
This has been some of the hardest work to get right for me too. Take your time check the bends often. Do little bits at a time. The tight bends would cause the teeth to bend up, so I had to bend them back straight and flat by hand. The metal is very hard and springy so over bending was required.
Hope that helps. I hope to get a digi camera soon and I’ll try to get pictures and a real journal going.
Hafte
Thanks Hafte,
I just read the post about only going 3/4 way round the tip. This largely solves the problem for me as it is the final bit that seems to cause me hassle, so I think that I will take this approach! I would still welcome pictures of how you actually manipulate the edge in the bending tool - I find it quite hard to get a constant bend radius and tend to have to work it a lot before I get anywhere close to a constant arc.
On a design note, I don't think that my tip design was that conducive to bending because I have quite squared off ends, so rather than a constant large radius I have 2 tight bends with straights between. I would advise people to avoid this kind of design for your first few attempts!
B.
I just read the post about only going 3/4 way round the tip. This largely solves the problem for me as it is the final bit that seems to cause me hassle, so I think that I will take this approach! I would still welcome pictures of how you actually manipulate the edge in the bending tool - I find it quite hard to get a constant bend radius and tend to have to work it a lot before I get anywhere close to a constant arc.
On a design note, I don't think that my tip design was that conducive to bending because I have quite squared off ends, so rather than a constant large radius I have 2 tight bends with straights between. I would advise people to avoid this kind of design for your first few attempts!
B.
edge bending
Thanks to hafte for the reply, it saved me a lot of typing. Here are a few additional tips. I have had no problems with the edges, and I wish that was true for all of the other processes, but given the fact that I have been a full time blacksmith,sheetmetal, and tubing bender for 25 years the edge part should come easy. My methods follow hafta pretty much, but I do use a hammer. Overbend the radius slightly then lay edge flat on some MDF or PE and hit it. This will open the curve up and also flatten the twisting. I also use a ring roller that has been modified, but have it mounted under a piece of MDF with just the rollers protruding. The edges can be feed in on the same plane as the grooves in the rollers. This is near the edge or the board, and it has an old ratchet wrench handle attached in place of the crank arm for easy access. Good luck. Feel free to call my cell. I think you have it from past PM, if not PM me.
Bambi,
I tried using the same ring roller that I believe you have described. Then I found a post about a tube bender. This bender is used for bending break and fuel lines in autos. I tried using that and it worked fine with the exception that the flage on the edge wanted to bend in as you have described. I solved that problem with a short visit to the band saw and put a groove around the center roller. This holds the edge flange in place and makes for easy bending of edges. In fact I now have my son do the bending for both the skis and the sonwboards. This tube bender can be found at most any auto suply store. I think mine was about $10 - $15.
Mine looks like this one in this ad:
http://www.classicperform.com/Store/Tools/TBTHD.htm
Send a PM if you want a pic only I won't be home for a few days...
ra
I tried using the same ring roller that I believe you have described. Then I found a post about a tube bender. This bender is used for bending break and fuel lines in autos. I tried using that and it worked fine with the exception that the flage on the edge wanted to bend in as you have described. I solved that problem with a short visit to the band saw and put a groove around the center roller. This holds the edge flange in place and makes for easy bending of edges. In fact I now have my son do the bending for both the skis and the sonwboards. This tube bender can be found at most any auto suply store. I think mine was about $10 - $15.
Mine looks like this one in this ad:
http://www.classicperform.com/Store/Tools/TBTHD.htm
Send a PM if you want a pic only I won't be home for a few days...
ra