sizing the cutout on a sled

[Sliverfoot]

I was making a sled to hold a lithopane project that I wanted to try and the area that I removed to place the lexan in didn't cut out the same size as the mpc that was uploaded to the carvewright. I'm sure that this subject has been cover many times in the past but I guess I just didn't put in the right words when I searched the forum. .
I cut a piece of MDF 16Lx13W x3/4 and put it in my Cravewright. Instead of a 8 1/2 X 11 1/2 area removed to a depth of .25 I got a
5 13/16 x 7 1/4.
I think My mpc is ok so what did I do wrong when I put my board in?

[fwharris]

Have not looked at your mpc file but best guess is you said "yes" to stay under the rollers and during the measuring process the machine asked if you wanted to scale your project to your board size and you said yes.

[Sliverfoot]

Yea
I probably did, so in order to keep my pattern at the size that I designed it at I should be answering "no" to stay under rollers?
I'm not at the machine right now but I think I remember the machine giving me the option of "cut to size"? I said no.

[fwharris]

I did look at your mpc and your lay out does have 3 1/2" + on each end of the board so say "no" to staying under the rollers. Saying yes the machine will add 7" to your design size and look for a board that long and when it finds that it is not you will get the scaling message.

On the "cut to size" it is asking that after the carving is done to you want the machine to cut the board in the machine out to your design size, Say NO you do not want the machine to cut the board size out.

[Sliverfoot]

OK
Thank you. I'll run it again tomorrow night.

[SteveNelson46]

I was making a sled to hold a lithopane project that I wanted to try and the area that I removed to place the lexan in didn't cut out the same size as the mpc that was uploaded to the carvewright. I'm sure that this subject has been cover many times in the past but I guess I just didn't put in the right words when I searched the forum. .
I cut a piece of MDF 16Lx13W x3/4 and put it in my Cravewright. Instead of a 8 1/2 X 11 1/2 area removed to a depth of .25 I got a
5 13/16 x 7 1/4.
I think My mpc is ok so what did I do wrong when I put my board in?

Try this one. The recess is done as a "Pocket Cut" with the 1/8" cutting bit. It should cut much faster. Make the actual board 19" by 10.5", "Center On Board", and answer NO to stay under the rollers.

[Sliverfoot]

Thanks Steve
My wife has had me doing christmas decorations so I haven't had a chance to get out to the shop yet to try anything. I was wondering if making a cutout in the center would be the way to go instead of carving out the whole thing.
I was going to upload my mpc for the lithopane and I got a warning message: " The carvings on this project are arranged in way that may interfere with the machines mechanics requiring manual or automatic jig. Wide cuts acroos the board may interfere with the compression rollers."
Do I have to somehow rotate my design?

[t-townwilson]

Steve,
Please explain "pocket cut". I opened your mpc and saw "polylines". With which program were they drawn? I am unfamiliar with that term, but I have made several recess cuts in sleds, and if I can find a way to make them quicker, I would be excited! It appears that you drew a series of progressively smaller rectangles in .2" increments. Would this work with a conventional rectangle drawn in Designer 2.xxx, or does it require specialized software? I also remember seeing elsewhere on this forum that pocket cuts were not possible on CW, but if so, inlays could be done. Thanks for your response in advance!

[bergerud]

The way I do pocket cuts simply uses the connected lines tool. I go back and forth in the y direction to cut out the interior and then go around the perimeter to clean up. Pick a snap grid the same size or smaller than the bit diameter and fill the interior (copy-paste-connect as you go). Keep in mind that the machine cuts in the same direction as you draw. Change the snap grid to a size which is compatible with the size of the pocket perimeter and finish by going around the inside of the perimeter.

This has the advantage of minimizing the travel in the x direction. Also, since it is one continuous curve, the bit stays down. Pockets cut from separate paths require more cutting in the x direction as well as requiring the bit to go up and down at start and finish of each path. This takes extra time and does not give as smooth a floor.