The CT Dust Shoe is a fairly simple dust collection system designed specifically for the Carvetight spindle system. The CT is higher than other spindle systems leaving about 1/2" between the bottom of the chuck travel and the top of the board. It is in this space where the Dust Shoe is designed to be. Other spindle systems can use the Dust Shoe but the only with the extra complication of a removable top window which allows the chuck to pass through the Shoe during the board and bit measurement routines.
The Shoe requires only a small shop vacuum and with a small cyclone and auto switch can make for a dust system which requires very little user attention. One can quickly get used to not dealing with carving dust.
The Dust Shoe works very well in normal carving. The cutting bit naturally throws the chips right at the vacuum intake of the Shoe. In other operations such as milling deep pockets or routing with the fancy bits where the chips fly in all directions, the Shoe is not quite as effective.
The Shoe bolts to the bottom of the y carriage using the screw holes of the board sensor. For this, it is better to use longer screws (1 cm 3m). The dust is removed from the Shoe through an elbow pipe which pivots using a small RC car ball bearing (R1212-2RS). A hose goes from this pipe, is strapped to the top cover, and exits though the handle on the right side of the machine. No permanent machine modifications are required.
The standard, swinging bit plate has to be replaced by a stationary one because the swing of the standard bit plate interferes with the Shoe. This results in a slight reduction of the maximum board width from 14.5 to 14 inches. A fringe benefit of this is that the bit plate is quiet and no longer fails to swing out. Replacing the bit plate does require removal of the right side cover of the machine and the locking plate.
The Shoe can be made out of hard wood or cast acrylic. If one does want to use cast acrylic, I still suggest you make your own prototype out of wood first. Machines are different and many of the parts are a challenge to to get right. Expect a few setbacks along the way.
The Shoe is designed to only require the 1/16 carving bit and the 1/8 cutting bit. These must be sharp and in the case of case acrylic, they should probably be new.
I use carrier boards to carve all of the Shoe parts. The carriers can be cut out of any planed wood or MDF (3/4"). The carrier boards have 1/2" deep cavities cut into them to carry the pieces to be made. The 3 X 4 carrier is for the Shoe body. The 3 X 3 is for the bearing cap and the pipe. Simply cut them out using the center on board option.
It is important to be able to get the piece in and out of the carrier board while the carrier board remains in the machine, while at the same time, the carrier board has to hold the piece fast. Tape is probably not good enough. Screws which clamp the edges from the top would be good. Side screws from the right is what I used but one must be careful not to push the piece off center in the cavity. I make the piece a little wide and sand it to a close fit. A little tape on the side of the piece can make it snug if it is a little narrow.
The carrier board procedure is designed to minimize the errors involved in double sided carving. The carrier board stays clamped in the machine so that the board is only measured once. It is not important that your machine centers the carving on the carrier. As long as the same machine (with the same calibration) that cut out the cavity in the carrier is used, the carving should be centered on the piece. That is, if your machine is consistently off center, it should not matter. (This is not the case for double sided carving where the whole board is flipped. Before you carve a part, you can test this consistency. First, load a project which simply drills a 0.1" deep, 1/8" centered hole in the piece. If the hole is centered in the piece, you can, without removing the carrier, proceed to make the part knowing that it will be centered. If your machine is inconsistent, you may may have to use the alternate coordinate procedure which I outline later in this thread.) Also measure to make sure the cavities are really 1/2" deep.
The basic procedure is to carve the rear of the carve in the normal way by centering on the board. When the rear is done, one loads the front project mpc (the front and back are two separate project files) without releasing the carrier board and continues through the setup until the bit starts to do the board touch. At this point, press STOP. Choose the option 3) Jog. Use the arrow keys to move the board into an x position where you can flip the piece. You can move the carriage out of the way in the y direction by hand. After the piece is flipped, move back to a touch position and continue to carve the front. This procedure is laid out in more detail in the next post on the instructions to carve the shoe body.
Upload the top and bottom projects to the card. (The top is on the back side of the mpc but will carve as if one sided.) You will get auto jig warnings because the Designer boards are so small. Choose MANUAL jig. Choose best or optimal for wood or optimal for acrylic.
The shoe body is carved by first carving the top. With the piece secured in the 3 X 4 carrier and in the machine, simply load the top project and go through the procedure to do a centered carve.
Stay Under Rollers - press 1) YES or 2) NO
1) Keep Original Size? - press (1)
1) Center On Board - press (1)
Cut Board To size? - press 2) NO
Be ready for when the board touch starts ("finding surface" on the display), press STOP and choose 3)Jog. Use the arrow buttons to jog to where the bearing hole will be carved on the piece (right front of the piece). Press ENTER to do the touch. ( "Select Cut Through Depth (0.500)" message - press (1) ) Continue with the bit loads as instructed and carve the top.
After the top is carved, do not to release the board and do not try and remove the piece. Load the bottom project and continue through the centered carve procedure as above. The board will not be remeasured. Be ready for when the board touch starts, press STOP and choose 3)Jog. Use the x arrow buttons to move the piece into an accessible position between the rollers, then move the carriage out of the way by hand over by the swinging bit plate. Loosen the side screws and use two wood screws in the pull holes to lift out the piece, flip it, and re-tighten the side screws. Now use the arrow keys to take the bit back to a place on the carrier board near the piece to touch. Press ENTER to touch on the carrier board. (This especially important if your piece is less than 1/2" thick. This uses the depth of the carrier board cavity as the 1/2" reference instead if the actual thickness of the piece. There may be a little air carving if your piece is thin.) Continue with the bit loads as instructed and carve the bottom.
(The 1/16 cutting bit is only used to cut the shallow brush slot. If you do not have a 1/16 cutting bit, you can use the 1/16 carving bit instead.)
(When finished, check the front - back alignment by looking at the mounting holes from the bottom. The holes were drilled from the top and the counter sinks were milled from the bottom. If they are not lined up, you may have some trouble shooting to do or you may have to use the alternate procedure outlined later in this thread.)
Upload the bearing cap bottom and bearing cap top on optimal. The bearing cap is a carve similar to the body but you use the 3 X 3 carrier and the 1/8 cuttong bit is only used on the bottom. This time you carve the bottom first. Stop 3)Jog to the bearing hole (middle of piece). Follow the same procedure as the body, touch the second side (bearing top) on the carrier.
After cleaning up the edges of the cap and making sure the bearing fits, you have to glue it on. (If you are making it out of cast acylic, you need a solvent cement like Weld-on #16.) I glue it on with the bearing in place while holding the shoe vertical against a horizontal flat surface. After a few seconds, pull out the bearing and press a together little harder.
After the glue has set you will have to "port " the shoe. That is, hand carve the out port hole with a Dremel. Make it as big and as smooth as possible without going too far down into the brush slot. Stay away from the thin top edge of the cap where the window will slide under.
The bit plate is a single side cut out of material which is 1/4 inch thick. It really needs to be cut out of some strong material. It does not fit in the carrier boards and so you are on your own figure a way to cut it out.
One has to take off the right side cover (two 10mm bolts on the post tops and two screws on the bottom). Then the lockdown clamp arm has to be dropped down away from the bit plate (three Allen screws). Pop off a C clip and the old bit plate drops off. The new bit plate fits on the same pin but also fits snugly into the cavity in the casting. One may have to sand the edges of the bit plate to get it to fit all the way up. Then put on the washers and C clip that were on the old bit plate and put back the lockdown clamp arm.
The C machine bit plate has a hole for the touch. I think this is only required for the C machines. (Without the hole, a C machine will go into a load bit loop after finding the board too low.) I have not tried a bigger bit that will not fit in the hole. There is some room here for experimenting. The bit plate A-B mpc has no hole since I do not think they need it.
The bottom edge of the end of the bit plate (under the new touch hole) has to be rounded so that it does not catch on the shoe when the shoe slides under. (It is easier to round it by hand then to have the machine carve it in a double sided operation.) Also where the bit plate stops the carriage could be trimmed down if the bit does not touch in the middle of the bit plate hole.
The window is the top of the shoe and is the most important part to be transparent. It can be as simple as a plastic washer or a little fancy with a cup glued in the center.
Very simple cut out, use double sided tape to hold a 2X2 X1/16 inch piece on top of a board. (Stick the double sided tape to the protective plastic not the acrylic itself!) You may find your own way.
For the QC and the Rock, these windows have to be easily removable. I put a small screw in the shoe and a small notch in the window edge. The window slips under the bearing cap overhang and the notch slips past the screw. A little twist and the window is on. One could also just make it a press fit.
For the CT, one would not be removing the window very often. I also made a little insert to reduce the window hole to a minimum while still leaving space for the bit adapter to fit through. It is milled from 1/4 cast acrylic. (One could cut and paste it onto the bit plate mpc and mill it at the same time.)
Also there is a milled CT window with the cup built in. This one would have to be wet sanded and polished to be see through.
Which windows you want depend on how you use your machine.
Upload the center pull hole as well as the pipe bottom and top on optimal. After, the pull hole is drilled, the bottom is carved and then the top following exactly the same procedure as the Shoe body and the bearing cap. On the bottom, STOP 3) Jog, touch near the middle of the 3 X 3 piece and on the top, STOP 3) Jog, touch on the carrier.
(It is this carve which requires the most accuracy. After the pull hole is drilled, measure to see how well it is centered in the y direction on the piece. If it is not centered, there is no point in continuing. Either re-measure the carrier and try again or use the alternate coordinate procedure.)
The two halves of the pipe are carved from both sides with a thin layer left between the sides instead of tabs. The thin layer makes it easier to cut out and glue. It is important to touch on the piece for the first side and then touch on the carrier board for the second side. Some adjustment to the carving depth might also have to be made. Different machines may carve to different depths. You may, with trial and error, need to change a carving depth. The bottom is easier to alter.
(The following trick might save the carve: If the carve is too deep and is carving all the way through at the start of the second side, you can raise the head slightly with the crank until you get the thin layer. You have a little time to do this before the bit gets to the pipe. It is worth a try since the carve will otherwise be a loss.)
After carving it, cut out the pipe halves with a Dremel by cutting along the outside perimeter of the carve leaving a skirt around the pipe halves. Clean up the bearing end and, using a file on the mating surface, get the bearing to just fit over the end. Apply glue to the skirts and clamp together. Use the bearing as a clamp and rubber bands or string. After the glue dries, sand off the skirt (leave it a little proud) and clean up the ends. The bearing should be a press fit. One would like the bearing to be tighter on the pipe than in the Shoe so that the bearing can be easily removed for periodic maintenance.
(The pipe is delicate and using too much force to attach the hose could break it. Use a pair of long nose pliers and/or some heat to spread the hose before slipping it on. This, however, should be done later when fitting the Shoe and hose into the machine. The hose will probably need to be twisted to take advantage of its natural curve.)
Last but not least is the brush. It is very important to block the horizontal escape route for the chips. I use window seals that I got from the local glass shop. They are the same as some door brushes. There are two rows of bristles imbedded in a fiberglass like backing and sometimes they are called fin seals if they have a "fin" between the rows. You only need one row. I used the scissors in my Swiss army knife to carefully it out. A bit tedious. If you used the 1/16 cutting bit to cut out the slot in the shoe, you can press fit the brush in with a small watch screw driver. Just work your way around twice. If you used the carving bit, you will have to glue it in. If the bristles are too long, you may have to trim them. They should just be slightly longer than the gap to the wood.
I was hoping the someone would find some better hose. There are a lot of hoses out there. Not so many 1/2 or 5/8 inch though. We ideally would like 5/8 ID clear, smooth bore, wire reinforced, antistatic, flexible hose. Some experimenting and product research is required here.
As to how to get the hose out of the machine, I have found a way out which does not require any machine modifications (see pictures). The hose goes down behind the right hand cover, has a loop and then goes up and out the hole under the handle. This is the method I recommend while you experiment with the Shoe. This is opposite to the way I have my hose and it has the disadvantage that the hose is longer and it is vertical at the Shoe when the carriage is to the left. This means that the bearing moves more during carving that the other way around. If you later decide you like the Shoe, you might want to make a hole somewhere. One could also get the hose out through the pluged (crank) hole above the handle if one puts in an elbow.
The hose is held to the top of the machine between the clear cover and the flex cable slot by either zap straps or tape. Different machines are different: some have little clearance between the flex and the slot side, and you may have to use tape. You have to experiment a little with the right place to attach the hose. The lengths should be as in the pictures. Move the carriage back and forth to find the best length.
The dust shoe is attached to the carriage using the board sensor screws holes. Crank the head all the way up. Remove the board sensor screws. While keeping the board sensor in place with a finger from behind, place the shoe over the board sensor and screw it on using 1 cm long, 3m screws. While tightening the screws, keep the board sensor pressed all the way forward in its cavity with you finger from behind.
The bearing should be a press fit onto the pipe and should always stay on the pipe. The pipe and bearing are more easily installed into the shoe when the carriage is toward the left and the hose is vertical. The bearing should be a snug fit into the shoe. If it is loose, use a small piece of masking tape to make it snug. Before taping the hose to the cover, twist the hose so there is no torque on the bearing and pipe. The hose should clear the z truck as the carriage moves back and forth. For now, just let the end of the hose go into the cavity behind the side cover.
The bit plate installation requires removal of the right side machine cover. Remove the two 10mm bolts from the top of the cover and the two small screws on the bottom and remove the cover. The locking bar which is just under the bit plate has to be dropped. Undo the three Allen bolts and lower the locking bar out of the way. Remove the clip from the bit plate pivot shaft and remove the bit plate spring and washers. Place the new bit plate over the pivot shaft and push it up into the cavity. The new bit plate should be a tight fit up into the casting cavity. Make sure it is pushed all the way up until it hits the top. Now move the carriage over to the bit plate to test how the shoe and the bit plate line up. Some trimming of parts may be required. Test to see where the bit touches the bit plate. You may want to remove some material from the bit plate where the carriage hits it to get the bit centered in the touch hole. When all looks lined up, put the original washer or two and clip back on the pivot shaft so the new bit plate is held up tight. Lift up the locking bar, hook it back on and put back the three Allen screws.
As the machine cover is replaced, one has to loop and feed the hose through the handle hole in the cover. The hose should come straight down, then forward and loop up to the handle hole.
A simple mini shop vacuum is all that is needed to run the dust shoe. (The larger, low vacuum high volume DC systems will not work.) One must make an adapter to connect the 1/2" hose to the vacuum.
Dust Shoe Prototype I Project
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