Dust Shoe Prototype for the Carvetight

[bergerud]

Sallen, I too have made sawdust out of 6 attempts at the pipe carve. It seems that my machine is not as closely calibrated as some. The pipe consistently carves through on the top cut at the edges of the inside tube. I give up!!

What we need is a better method that does not rely so much on machine calibration. If the depth is a problem one must use a shim for the touch or adjust the depths of the mpc. If it is line up of the front to back, let me suggest another technique. The pipe mpc here is split into two files. One for the back and one for the front. The one for the back has a center hole drilled in it (You will have to load the 1/8 cutting bit just for the hole.) After the back is carved, flip it over and choose jog to position instead of center on board. When you get to jog to edge or center, pick jog to center. Jog to the hole so that by pushing the truck down, you can push the bit into the hole. The y will line up automatically since the truck will move manually. It is the x that requires some effort since you have to use the arrow keys. Now away you go. You cannot get much better than that for line up I do not think. The method should be independent of the machine calibration. I have planned to experiment more with this method but have not gotten to it.

Don't give up. Hell I will send you a pipe if you cannot carve one.

[henry1]

Sallen, I too have made sawdust out of 6 attempts at the pipe carve. It seems that my machine is not as closely calibrated as some. The pipe consistently carves through on the top cut at the edges of the inside tube. I give up!!

Lower the depth on the inside to 0.280 and the outside 0.345 that should help work for me we will get it yet right Dan

[rockflier]

Bergerud, thanks! I tried that on one carve using 2 separate files for top and bottom. I will try again using your files and Henry's depth settings also if the first one does not work. I cannot thank the members enough for all the help, encouragement, and comradeship. Good job guys!

[rockflier]

Henry, I went as far as using .275 inside and .325 outside and had the same problem. I am going to use Bergerud's technique and go from there.

[henry1]

sorry about that wish you luck

[bergerud]

I finally had a chance to try the second prototype with the window cup. I have to say it is very good. I just completed a 1 hour carve of ebony. I did not see a speck of ebony in the machine. Although not the most grueling test, it was a good one. The Shoe was not always over the board and the carve was deep, through the board. There was no dust on the carving, the sled, or the machine. See the after pictures below.

I think that this may be better than my Dust Cap that I have raved about for the last year. I like that I can see the bit. I think that the window cup, added for chucks which plunge lower than the CT, actually makes the shoe work better. Higher velocities and vacuum are moved closer to the board.

You guys have to try this.

http://youtu.be/LvVN7MlODlU

[Sallen1215]

Love it!!! bring on the MPCs for me to try out lol

[bergerud]

I will but I have to do some alterations for the Rock. The hole has to be bigger, but it is not so easy. Right now I am working on laying out my method of double sided carving. It is no good if people get frustrated trying to carve these parts. The pipe, as you well know, requires some serious accuracy. I am afraid that the jog to center hole is still not good enough. I hope it works for rockflier. But like I say, when the pipe works, I feel lucky!

What I do is first, make sure the y offset is set so that centering in the y is as accurate as it can be. I do not care about the x, it is hopeless. Then I use the machine to cut out a carrier board with a 3X3X1/2 cavity in the "center" for the acrylic. (Check that the cavity is y centered and really is 1/2 deep.) I cut out the acrylic so that it fits snugly (not too tight) in the cavity. (It does not matter if the acrylic is less than 1/2; the carrier board will be the height reference for the 1/2 inch.) With the mpc in two separate projects, I carve the back in the normal way by choosing to center it. After the back is carved, without releasing the carrier board, I load the front project and proceed to go through all the same steps as for the back as if the board was flipped. I have the jog to touch turned to (ON) and when the machine asks for me to jog, I move the board instead into a position between the rollers which allows me to pull out the acrylic and flip it over. (This is sometimes difficult in the limited space. Special tools or hooks are useful as is masking tape. The carriage can just be moved out of the way by hand.) Then I do jog to the touch spot (which may be on the carrier or on the acrylic depending on the part and side). After that and the bit changes and away it goes.

The trick of not releasing the carrier board means that the machine uses the same board dimensions for both sides. This means that the x and y centers will be in the exactly (+/- 0.005 or better) in the same place. When the piece is flipped, the x stays the same no matter what. If the piece, however, is not centered precisely in the y, the error will double when it is flipped. This is why the y offset is so important. (It is also an easy calibration to adjust.) I have yet to find a better way. I am afraid that if you have and an uncalibrated, or worn out machine this may be the only way you will be able to carve these double sided parts.

[henry1]

I will but I have to do some alterations for the Rock. The hole has to be bigger, but it is not so easy. Right now I am working on laying out my method of double sided carving. It is no good if people get frustrated trying to carve these parts. The pipe, as you well know, requires some serious accuracy. I am afraid that the jog to center hole is still not good enough. I hope it works for rockflier. But like I say, when the pipe works, I feel lucky!

What I do is first, make sure the y offset is set so that centering in the y is as accurate as it can be. I do not care about the x, it is hopeless. Then I use the machine to cut out a carrier board with a 3X3X1/2 cavity in the "center" for the acrylic. (Check that the cavity is y centered and really is 1/2 deep.) I cut out the acrylic so that it fits snugly (not too tight) in the cavity. (It does not matter if the acrylic is less than 1/2; the carrier board will be the height reference for the 1/2 inch.) With the mpc in two separate projects, I carve the back in the normal way by choosing to center it. After the back is carved, without releasing the carrier board, I load the front project and proceed to go through all the same steps as for the back as if the board was flipped. I have the jog to touch turned to (ON) and when the machine asks for me to jog, I move the board instead into a position between the rollers which allows me to pull out the acrylic and flip it over. (This is sometimes difficult in the limited space. Special tools or hooks are useful as is masking tape. The carriage can just be moved out of the way by hand.) Then I do jog to the touch spot (which may be on the carrier or on the acrylic depending on the part and side). After that and the bit changes and away it goes.

The trick of not releasing the carrier board means that the machine uses the same board dimensions for both sides. This means that the x and y centers will be in the exactly (+/- 0.005 or better) in the same place. When the piece is flipped, the x stays the same no matter what. If the piece, however, is not centered precisely in the y, the error will double when it is flipped. This is why the y offset is so important. (It is also an easy calibration to adjust.) I have yet to find a better way. I am afraid that if you have and an uncalibrated, or worn out machine this may be the only way you will be able to carve these double sided parts.

I never jog this is my first can you explain how to do it again thank you in advance

[bergerud]

I never jog this is my first can you explain how to do it again thank you in advance

I usually have my machine configured to jog to touch. On the keypad press 0 - 5 and change the JOG TO TOUCH(OFF) to (ON). Now when ever you start a project, the machine will stop at the point where it would touch and ask for you to jog to a touch spot. This gives you a chance to move the board around as well as freedom to touch where you want. Where you touch is important for controlling the depth of some carves. I always jog to touch the bit right where the bearing hole is to be carved. That way the depth of the bearing hole is always right. On the other side I would just press enter and touch as normal on the carrier board. Touching on the carrier board makes sure that the second side is carved 1/2 an inch above the first side because the cavity in the carrier board is 1/2 deep. This is especially important if the thickness of the acrylic is not exactly 1/2. (Mine has been 12mm.) For the pipe, I just let it touch the carrier board on both sides.

(You can also just use JOG TO TOUCH any time by pressing STOP as the machine starts its normal touch. It will pause and allow you to jog.)

As I mentioned before, the jog to touch gives you the opportunity to move the board. This is important to allow you to flip the piece. After the first side is carved, the piece will be left under the front roller. With the jog, you can move it to a spot between the rollers where you can get at it.

I hope this method will help with the accuracy problems of machines which have lost their calibration. I will provide more specific instructions for each piece when I later post the files.