Adjustable Bottom Mold

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petefromluck
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Joined: Tue Oct 14, 2014 6:59 am

Adjustable Bottom Mold

Post by petefromluck » Tue Jan 27, 2015 11:24 am

Good Afternoon Guys!

I have been creating all of my molds with the use of a CNC machine that I am able to use for free. I have been building these molds in my CAD program as on piece. (meaning I include my camber, tip and tail)
This creates awesome results in my press but it is super time consuming - it takes about 12 hours to cut out all of the MDF. Because the CNC is not located near my home, this has become a pain in the a$$.
I'm looking for advice at making a mold that could be adjustable depending on what type of ski I want to make. I am looking for a base camber of 4mm - 8mm and then be able to make different tip and tails that could move around on my camber base. Most skis that I have been building range from 170-195.

I appreciate any help. Cheers!

switzch
Posts: 46
Joined: Wed Jan 05, 2011 7:35 pm

Post by switzch » Tue Jan 27, 2015 7:33 pm

My method which is copied from someone on here was to keep the camber locked but have replaceable tip/tail blocks. The key thing is that the tip and tail block is milled to fit exactly on the bottom camber (it may need a slight curve) and also the end is exactly the same width of the mdf sheet that will fill in the gap between the two blocks. You can see in the picture below that the tip tail blocks have a metal piece holding it in place but is also adjustable. The middle piece in this picture is not painted green so its easy to see where it butts up against the tip/tail blocks.

I have read that some people do this with a flat camber and use heat differences on top/bottom to adjust camber.

Image
winter is coming..

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Akiwi
Posts: 370
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Location: Olching (Near Munich) Germany

Post by Akiwi » Wed Feb 04, 2015 5:39 am

I'd also be interested in what options there are also.
If I am goindf to build a form, It would be nice if it was adjustable, or at least parts could be easily swapped out to account for different shapes and lengths.

I saw one recently for Vacuum that looked pretty interesting.
It was an aluminium sheet where the camber and tips could be adjusted with screws making an infinitely adjustable shape table.

Unfortunately I can't find where I saw it.

satch
Posts: 49
Joined: Wed Mar 28, 2012 5:38 pm

Post by satch » Wed Feb 04, 2015 10:18 am

Maybe you saw my adjustable mold:

http://skibuilders.com/phpBB2/viewtopic.php?t=4821

It's a zinc coated steel sheet. Not sure if it's 0.5mm or 0.8mm. You can adjust rocker/camber every 150mm. It measures 2,15m in length and there is about 50cm space between the screws. Below the sheet metal there are L-shaped ribs helping to get a flat base. If you need any further information just ask.
Cheers,
Sebastian

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Akiwi
Posts: 370
Joined: Thu Jan 15, 2015 7:48 am
Location: Olching (Near Munich) Germany

Post by Akiwi » Wed Feb 04, 2015 12:57 pm

That is exactly it. Looks awesome!
How have you attached the l ribs to the steel?
And how adjustable is it for the tips and tails?
How easy is it to adjust the camber or rocker?
How are the screws attached so they can rotate to allow the different angles, particularly in the tip and tail?

I must say, it is the most interesting looking mould I have seen.
Would love to see more of it, and hear your opinions on how well it works, if it could be improved etc. look snore or less exactly the direction I want to go.

satch
Posts: 49
Joined: Wed Mar 28, 2012 5:38 pm

Post by satch » Thu Feb 05, 2015 3:29 am

I didn't connent the ribs and the sheet metal. The sheet is just lying on top of the ribs. Haven't had any problems so far. Maybe I could glue them together to get my bases even flatter. The tightest radius I've done so far was about 350mm. I wouldn't go much lower because it would mean permanent deformation for the sheet metal. On every rod there is a nut below and on top of the mold surface. So it takes some time to change the camber/rocker curve.
I'll post some more pictures of detailsfor you if you like. Might take some time as the mold is in my father's basement. Won't be there until end of february

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