Dust Shoe Prototype I Project

[bergerud]

The dust shoe operation is designed to be simple on a machine equipped with the Carvetight chuck if one uses only the standard bits (1/16, 1/8, 3/16 carving and cutting bits). The dust shoe does not interfere with chuck, adapters, or these standard bits and should be virtually trouble free.

In the case where one wants to use a decorative bit which has a diameter larger than the hole in the window, one will have to remove the window. In this case, the dust collecting effectiveness of the shoe will be significantly decreased. If a certain bit is used often, one might make a custom window for it.

As a further complication with the larger bits, the touch hole on the bit plate is too small and the bit will touch too high. In a mult-bit project, this could be bad. If, for example, a standard bit is used to touch the bit plate and to touch the board and then a larger bit is loaded and touches the bit plate too high, the larger bit will cut too high. This is an area for further development. A lower custom metal bit plate may be what we need. (I believe that the A ans B machines with the CT do not need the touch hole and so need not have this problem. A simple bit plate without the hole is all that is required.)

If the dust shoe is used with other types of chucks which come within 1/2 inch of the board surface (Rock and QC), one will have to remove the window during the bit loading and board measurement stages and replace the window during the carves and cutting. (It may be possible to block the z truck from going too low. Something you can experiment with.)

Warning: Some of us like to just let the machine measure the carving bit over and over instead of switching in all the right bits at the beginning of a multi-bit project. Then, when the machine measures the bits to be the wrong lengths later, we just press continue. This is ok as long as the bits later measure too short. If, however, the bit later measures too long, the machine gives a good hard second push on the bit plate. I have had this break a thinner acrylic bit plate.

The bearing on the pipe will get that fine dust in it. It is just a matter of time and the bearing will stiffen up. Until we can find a bearing with better seals, we will have to keep an eye on it. There is a cavity behind the bearing where dust may collect and get into the bearing. One might experiment with, say, a felt washer behind the bearing to block the dust.

[bergerud]

Double sided carving small parts where accuracy is important can be frustrating on the CW. The CW does, in fact, carve and cut very accurately once it finds the board! The problem is that the board sensor never seems to measure the same board to be the same size twice. This variation in measurement makes it a bit of a crap shoot when we want 1/32 or better accuracy between the sides of a double sided carve. The trick of leaving the carrier board clamped in the machine and flipping only the work piece solves the x accuracy problem since the x does not change for the flipped piece. The y accuracy, however, depends on the consistency of the machine. If the machine is inconsistent, measuring the width of the carrier different than when it was made, the y of each side may not line up. The following procedure outlines a way to set up the carrier board and machine so that one can accurately and repeatedly carve with y centered on the piece. A simple centered hole project is run first to determine the coordinates of the center.

Before the project is carved, load a project that just drills a shallow 1/8 th hole in the center of a 3X3 piece using my carrier board.

1. When the question comes to 1) Center On Board choose instead to 2) Jog To Position
2. It will ask for the 1/16 carving bit (to jog with) but put in the 1/8 cutting bit instead.
3. Press STOP when it starts the bob to touch the board. You will get the option to 3) Jog.
4. Jog to the approximate center of x with the arrow keys (center with the half holes on the carrier) and write down the x center coordinate from the display. Accuracy in x is not crucial.
5. By hand move the carriage to the half hole in the carrier board on the keyboard side and push the bit into the half hole and up against the 3X3 piece. Write down the y coordinate on the display. (Call it a.)
6. By hand move the carriage to the half hole on the other side of the 3X3 and push the bit up against the piece. Write down the y coordinate. (Call it b.)
7. Calculate the y center (a+b)/2. You now have the x and y coordinates of the center of the 3X3 piece. (Independent of whether the cavity is cut in the center or whether the machine is calibrated!)
8. Now move the bit by hand or with the arrows to a place to touch and press enter.
9. After the touch you will be asked to Jog to project, choose 2) Center.
10. Instead of using the arrows, key in the x and y coordinates you have written down and calculated. (Careful: the first digit has to be pressed twice. Once just to change the mode. If you screw up, you can press STOP.)
11. Press enter and it will ask for the 1/8 cutting bit - just keep going and drill the hole.

Get out the calipers and check that the hole is really in the y center of the 3X3 piece. It better be. Now you are set set up to do accurately centered carves using those same x and y center coordinates with the Jog To Center option. These numbers will be good as long as the carrier board is in the machine. (Unless you abort a project whereas all will be lost!) The thing is that you have to be able to hold the piece in the carrier board and also be able to easily get it in and out of the cavity while in the machine. Screws or a clamp or something. This is also another job for the jog. You can use the jog to move the piece to an accessible x position. The carriage can always be moved out of the way in the y direction by hand. It does not matter when you flip the piece so start the second side project setup and then flip the piece later during the jog to touch step.

(Note that for a project which uses only the 1/8 cutting bit, one can find the coordinates as above and just continue the project. If the project starts with the carving bit, however, one will not get the chance in the above procedure to change bits before the carve. In this case, one has to run the simple hole project first.)

[bergerud]

OK. I think I am finished the start of this thread. I have tried to lay out all of the instructions and files to make the dust shoe. (I will still be making corrections and improvements I am sure.) This is an interesting posting experiment in itself. To have all of the information up front with no other posts.

For the rest of this thread, I hope that members will now post questions, comments, and results relating to the dust shoe's creation, use, and improvement.

[b.sumner47]

Thank You, for all your efforts and time.Very much apprecated.


Capt Barry

[bjmwoodworker]

hi well I have been trying to carve your project but keep having a problem with the dustcap bottom .. I can carve the top ok but when I try to carve the bottom piece ...for some strange reason I keep getting a z-axis stall message and my only option is push stop button! I tried reuploading the mpc to the card and I still get the same result... apparently my designer 2.004 software is adding something to the upload process any thoughts? anyone else having this problem? any suggestions would be welcome!!

[bergerud]

I cannot understand why you would be getting a z stall. The carve is quite shallow. When do you get the stall? Sharp bit? Cast acrylic? I do not think it has to do with 2.004.

[bjmwoodworker]

well I dont understand either I tried to carve the mpc in hardwood and Corian I get the stall after it does bit find . btw is the bottom mpc really supposed to be .75 unlike the top which is .5 thick?

[bergerud]

The top and the bottom are 1/2". The carrier board itself is 3/4". I think your stall might be a different problem. Try a simple carve on a scrap board and see if you still get the stall.

[bjmwoodworker]

well I still think that the problem is with the mpc it carves the top of both versions just fine, but it doesnt carve the bottom of the dustcap version because it is showing .75 for board thickness instead of .5 as the other three mpc do. I am now confused which dust cap dust collector project to use. one is labelled Dustcap and one is labelled Dustshoe. Which one so you recommend that I use?

[bergerud]

I am sorry, I thought you were carving the dust shoe since this is the thread for the dust shoe. The dust cap is a much more complicated project. The dust cap does not work with the Carvetight or the Rock chuck because they are too big to fit through it. I use the dust cap with ER spindles. I think you need to be carving the dust shoe.

You are right, the dust cap bottom is 3/4.