No Measure Dowel Hole Making Jig

prusaprinters

This is a dowel pin jig for joining boards using dowel pins. It is used for holes in the edges and the faces. The jig allows you to drill in non-measured positions and match the mating board's dowel up exactly. It is currently designed for .375 inch dowels, but I could post other sizes (.25in, 6mm, 8mm, 10mm) if there is interest. There is a bill of materials drawing to assist in knowing how many of each part to print. A few parts have to be fabricated from metal and basic dimensions are shown for that purpose. Part #6 is made from a 3/8-16UNC hex head cap screw. If you buy two 4inch long ones you can make all four #6 and #7 parts. The groves in items #2 and #3 are to fit a rubber band that pulls the pins together clamping the edge of a board. The grip pads on the linkage allow you to squeeze it open. I may add an insert to the handle to adjust the dowel pin size for 1/4" and 6-10mm dowels. A new drill bushing will be needed for each size as well, which I might make a cutout for inserting it without disassembling the handle. This depends on the interest.Let me know in the comments. Print Settings Infill: 25% or more Notes: Part 1 (Handle) was printed with the outside flat on the bed without supports. You will need a 10"x10" bed. Parts 2-5 I printed flat with supports and a brim. I failed to produce a proper part twice due to shinkage lifting it from the bed and causing it to be curved. With the brim at 15 lines I was able eliminate it on all but one link. Printing them on edge should eliminate the issue, but the holes won't be as round. Since the will need to be reamed out with a drill anyway, it is not really an issue. Parts 2 & 3, print with at least 6 wall line count (WLC), and better yet solid. I printed them at 4 WLC and while they function fine the ends with the pin can twist a little and the increased stiffness would be beneficial. The pin holes will be slightly under size unless your printer is dialed in perfectly. This is good. Drill them out to .375" and .500" on part 2, and tap the smaller hole on part 3 at 3/8-16UNC or drill it out to .375" and epoxy the threaded pin in place if you don't have a tap. Run the bits as little as possible for a nice tight fit around the pins. Parts 4, print with 4 WLC or better. This is only needed for the tapped hole, not for greater strength. I used 30% infill. Tap the hole 3/8-16UNC. Drill the .500" hole to match your drill bushing. Part 5, 3 WLC is fine, with 25% infill. Drill the same as part 2. Part 9, I added this part to print as a temporary solution until you can make a metal one. Print solid. Part 12, Print nut side up without supports, 25%+ infill. The drill bushing is make of 1/2" tubing. I can post a version for 1/4" pipe which is .540" OD and .364" ID, which can be drilled out to .375", if there is demand. It maybe be easier to find. How I Designed This Drill your dowel holes with no measuring. To use it: Push the pins through to all be on the same side. Squeeze the handle and place it over the edge of your board, clamping it between the pins. It will self center. Tighten the locking knobs. Then drill your holes, sliding it down the edge. The location is not important, but if you like you can see marks thru the drilling hole. To make a 90degree joint, flip the jig and place it on the face and edge of the mating board, pushing the pins thru and pushing the pins up against the edge of that board. That should position the drilling hole precisely the same distance from the edge as the holes in the first board. Then take board #1 put the dowels in the holes and lay it flat on the board #2 with the two edges parallel, but offset just enough that the base of the jig does not touch it. Line up the perpedicular edges of the boards and clamp #1 down to #2. Then you can move the opening in the base of the jig over each dowel protruding from #1 which positions the jig horizontally. The pins position it vertically. No measuring it is required and the holes match up. This design was inspired by Tamar at https://www.3x3custom.com/tutorials/adjustable-dowel-jig Mine has a few more features, but it will still be helpful to see her website and video that explains how this type of jig is used. I wanted to increase the accuracy vs. making a wood one with hand tools. I wanted it to hold itself on the edge of boards so I added the rubber band actuated clamp. I also wanted it to have a lock that did not get in the way of flipping it over. One set of pins slides through to the other side allowing you to use the pins, and the broad base for squaring the jig to the work piece. If you are drilling away from the edge and cannot get the drilling hole the right distance from the edge of the board, try flipping it over or using the second drilling hole. For use well away from the edge, clamp board #1 down and used the base of the jig to locate off of it. The wide base has flats to clamp it to board #1 over each dowel. Updates from Original Release Updates from Original Release While I am pretty happy with the results from the first print, I have made a few improvements. The locking knob, I added a large chamfer so that the elephants foot of the first layers do not distort the gripping surface. The handle I plugged the nut hole so that the slicer will bridge it when printed without supports. I moved the locating boss out to the tips pf the base to align the two halves. I found differential shrinkage caused them to be slightly misaligned. The locating boss is slightly looser now. The chamfer around the slot was reduced to give better bearing area when using a drill stop collar. The assembly screws turned out a bit shorter than stated, and the heads did not quite fit flush, so I moved the nut a bit deeper, and countersunk the head deeper. To fix that issue on the already printed part I heated the nut on the end of the screw and pressed i gently into the hole, melting the nut in place about .02 deeper, and then used a countersink to cut the opposite side slightly deeper. None of the changes are significant enough to cause me to reprint it though. The results turned out very well and the fit is good on the moving parts. Category: DIY