Its pinewood derby time again...

[twelchPTM]

First before anybody gets upset, I am working on MY car for the dads race. My entry last year was Han Solo frozen in carbonite, Simple and easy to machine from one side only. This year I want to do something just as if not even cooler. I have a 3d model of the delorean from back to the future but I think I need to cut all four sides of my block and am not to sure on how to hold it in place especially once one side has already been cut. Any tips or tricks you guys can share?

[twelchPTM]

I've never had a post go this long without a reply, while i was waiting i continiued to bang my head on the wall and I think I shook an idea loose! tell me what you think....
I think, if i make a jig to hold my initial block of wood in place i can pack it with playdough to fill whats been cut away when I rotate it. sounds simple, but it an't be that easy can it?

[Brady Watson]

Just prepare the block to exact dimensions (meaning round numbers you can input into PWorks3D to define your material - uber important) - Make the block oversized at the ends (add 1.5-2" extra on each end) then screw or clamp the ends. Be sure to add tabs when you set it up so that doesn't 'free' the model while machining towards each end.

It is easiest to make the material the same on all 4 sizes. Mark your table where the material meets at the back (assuming Y dir flip) & mark the X0 end (which will really be -X since you'll X0 2" into the material) so you have a registration point when you flip it. Set your 0,0 point in PW3D to the bottom left corner. It defaults to the center...which is rarely used.

Others may suggest using dowels or other registration methods, but that is unwarranted for this. Pencil marks work fine (use a fine point pencil though) - and be sure you are rotating the material in the proper direction so that the toolpath matches the desired side.

-B

[jerry_stanek]

there had a video on two sided milling you may want to look at it

http://www.shopbottools.com/Training/Videos/Two.Sided.Machining.wmv

[twelchPTM]

I figured out the bit with the oversize work piece however if I m following the rules, I have to use the block that came in the PWD Kit.

[khaos]

Glue some waste wood to the ends for clearance. When done be sure that none of the 'un-sanctioned' wood remains. :)

[chiloquinruss]

If machined out of a block, do a 4 sided and when done cut the blocks off. Russ

http://hobby-tronics.lenzus.com/content/21775739/r/s_94543947.jpg

[twelchPTM]

i feel like i asked a silly question, I was trying to cut the block that cam with the kit with out adding on to it but it has become obvious that if I want to use the full length of the block I will have to add onto it to hold it, Also found out that the local council had no rule about adding onto the block as long as it fits final size regulations, district and national races have more strict rules regarding adding pieces to the block.
that being said thanks for the help and one last question, I don't think regular wood glue will hold up when I start cutting, any recommendations?

[Kyle Stapleton]

Wood glue with paper in between your two blocks will work fine.
It will give you a clean brake when you are done, this is how they turn bowls.

[khaos]

Wood glue with paper in between your two blocks will work fine.
It will give you a clean brake when you are done, this is how they turn bowls.

x2 this is the way.