Experimental Board Carrier

[bergerud]

This is good. We are learning things. I guess the clamp is not good enough on its own for uneven boards. I was thinking of having a row of holes through the tops of the sides so one could use some screws in cases where the boards were not so perfect. If a board is not flat and is above the rails in places, it could shift under the roller pressure.

[bergerud]

Just to be more versatile, I had thought to add these holes. They could be used for screws for uneven boards or pins to hold more elaborate fixtures.

[Wood Art 1]

Dan, you are a genius. Just got the first piece out of the Bergerud fixture. Worked just as advertised. Building it was kind of like copying a recipe for aunt Mary's fantastic cake. You know, substituting baking powder for baking soda and wondering why it doesn't taste like aunt Mary's. Well I didn't have 3/8 rod - had 5/16, didn't have 1/2" stock - had 5/8 plywood. Went ahead anyway. As you can see from the picture, I still have a few things to fix. Had some knobs (fit the 5/16 rod), painted the tops of the rails black and added a tool to set the top of the carving board 1/8" proud. Got it working, now to learn all the things I can do with it. PS. Couldn' get it to measure a 5" L board - 6 1/2" L board was OK (under both rollers). I will have to follow these postings religiously to figure out all the possibilities. Thanks for your inspiration, hard work and patience.

[bergerud]

Nice. You can only measure boards longer than 6". My trick was to measure a longer board and then switch in the shorter one.

Edit: it looks from the picture that you have the touch hole and blocks down at the opposite end as the design. You must have to do a bit of extra jogging.

I like the tool. I made (or had left over) 1/8" shims. I use them on top of the sides to set the 1/8" proud. I also, however, use them under the board when I am measuring a board I want to later drop down into the carrier. That is the trick to set up for sliding boards in and out.

[bergerud]

The CW machine is really very accurate at what it does on a board. The inaccuracy problems come from the machine not knowing exactly where the board is. The process of measuring the board is not nearly as accurate as the cutting operations are on the board. This can be a problem for double sided carving. If one wants the sides of the carve to line up with the same accuracy as the cutting operations, one cannot rely on board measurement. The two sided mpc project where you flip the board and remeasure is not very reliable. Methods with two mpc and jogging to place the carvings on each side works a little better, but, it depends on eyeball - push button accuracy and the bit just never seems to return to the exact spot.

I have tried many different methods. Some of which I am trying with the carrier base. What I would like to do is prove to you that it can be done by explaining a process which does always work.

First design a double sided, two mpc project in Designer on the smallest possible board. Also, design a carrier board with a pocket which will hold the small project board. Put the board for the carrier board in the carrier base with shims under it. Measure it, take out the shims, lower the board below the sides, clamp it, and cut the pocket in the center. Next, slide out the carrier and put the project board in the pocket. Slide the carrier board in and carve side 1. Slide the carrier out, flip the board in the pocket, slide it back in, and carve side 2.

The accuracy of the whole operation does not depend on "where the measured carrier board was". The machine cut the pocket where it decided center was and it knows now exactly where that is. This means that the machine knows exactly where the project board will be. Since the carrier base does not move during the swapping in and out of the project carrier, both sides of the project will be carved with the best possible accuracy. The same accuracy that the machine cuts with.

Now, I am not saying that this is the only method. It requires a "sacrificial" carrier board. The method, however, does prove that consistently accurate double sided carving is possible.

[bergerud]

Today I made a shorter, deeper carrier base. I think that maybe there should be a few sizes. This one will hold boards up to 12" long and 3" thick. (The first carrier held up to 18" long and 2" thick.) I was also thinking that a very long one would also be useful. One say which would hold up to 30" long and 1.5" thick.

[Sliverfoot]

Dan
I've been following this thread almost daily and I'm hoping to have this weekend free so that I can make your carrier. I'm anxious to experiment with it. I have looked at both the local Menards and Home Depot and neither handles 5/8 MDF. I have plenty of 3/4 MDF around the shop, other than the extra weight does it matter if I use 3/4? Otherwise I suppose I could pick up one of those white wood or oak edge glued panels that the stores sell and plane it down but like you've said MDF is cheap.
I can only echo what others have said. Thank you so much for taking the initiative and designing this carrier. It looks like something that will be a regular whenever I run a project. I wouldn't have a clue how to start designing something like this.

[bergerud]

You can use 1/2" or 3/4" MDF. I just like 5/8" because of some of the touch spots and it seems like the right size for strength. Give the 1/2" a try.

[Sliverfoot]

Ok I'll do that. I have some and both places carry it if I need more. I just thought that the 1/2 got a little thin for the touch hole.

[bergerud]

I just thought that the 1/2 got a little thin for the touch hole.

True. But then with 3/4", the first board touch can miss the board. Hence the 5/8". The 3/4" problem can be fixed with an under cut so the keypad side fits 1/8" over the squaring plate. Others have already used 1/2" but you could go either way.