Tapered Inlay Trivet

Instructions

If you have questions or comments about this project, please leave them in this thread: https://community.shapertools.com/t/multi-part-tapered-inlay-knowledge-thread/15054/6 The thread has a ton of detail about tapered-bit inlays. The project has two PDF files. One has the instructions (same as the text below). The other is a worksheet that has all of the project settings and sizes. A tapered bit inlay isn’t hard and doesn’t require and special manual dexterity. (Good for me, a guy with ten thumbs.) But you’ve got to be able to do three special things. I have hardware solutions that take all guesswork out of these. First, you need to have a way repeatably mount, remove and remount the trivet to Workstation in exactly the same position multiple times. I made a special shelf for this: https://hub.shapertools.com/creators/5fb124fb8009d8000f0ca018/shares/688b756040be7cb19827aacb If you have a different solution for mounting the trivet, of course that’s fine. The ability to dismount and remount to the exact same position is how the inlay can have tiny intricate details. So this is mandatory. Note that I don’t think double sided tape is a good option, because you risk moving the shelf when mounting/removing the trivet. Second, you need a way to make the Workstation shelf (including the special inlay shelf) level from front to back and stable. The extended WS table has a leg that makes this easy. Highly recommended. I made extra brackets so I can use the leg on all of my WS shelves. Here is a link to a simple bracket from 1/2 inch plywood: https://hub.shapertools.com/creators/5fb124fb8009d8000f0ca018/shares/68ab0583a460d41a6d790b1d If your WS shelf is not level front to back, your depth of cut will vary, and therefore (since you are using a tapered bit) your cut width will vary. That will probably mean a poor fitting inlay. So leveling the shelf is mandatory. Third, you need to make accurate manual Z touches using the tiny end of a tapered bit. I made a gadget that makes the manual Z-touch easy: https://hub.shapertools.com/creators/5fb124fb8009d8000f0ca018/shares/689b59d55ecb5867423e1ba4 My Z touch gadget might look like overkill, but I’ve used it dozens of times and it just works. If you’ve got a cheaper/better/faster solution let me know, but when using a tapered bit you’ve got to get the Z-touch right. If your Z touch is off, your depth of cut will be off, and that will mean your width of cut is off. Therefore an inaccurate Z touch will mean a poor fitting inlay. Accurate Z touch is mandatory. I suggest you print the PDF worksheet. Its got all the settings and sizes. The male parts come first. Cut the 3/16ths thick inlay material to these sizes (can be a little bigger but not smaller; I hand cut on a bandsaw — no need to worry about keeping corners square): Main leaf, yellowheart, 5.5 by 2 Rear shadow, white oak, 2.5 by .75 Tip shadow, white oak, 1 by 1 Stem shadow, white oak, 4.5 by 1 Stem, maple, 4.5 by 1. The grain runs with the long side on each part. Arrange the male parts on a single piece of MDF, about 11 by 5 inches, and attach the parts with double sided tape. Leave a little space around each piece as you tape it down. Now you have a parts/MDF sandwich. Attach the parts/MDF sandwich to a normal WS shelf (can be any normal shelf, but probably not the special inlay shelf, because the fence might interfere). Align in WS the normal way. However, take extra care to make sure the shelf is level front to back. (Use the leg from the extended WS shelf kit.) Scan and grid. Use a small grid pattern such as 1/8th inch. You can simply double click to grid — no need to probe the edges. Each male part has two files: One includes “taper” and the other includes “pocket.” Import and place each “taper” file on the appropriate piece of wood. Be sure to snap the file to the grid. UPDATE: My current thinking is that the separate pocket file isn't needed and wastes time. I'm keeping the prior description of the two-file process, but see the update below for how to produce the parts using only the "taper" files. Mount the tapered inlay bit and do a super careful and correct Z touch. Make outside cuts using the following exact settings (the settings are on the PDF worksheet): Depth: .15 Offset: 0 Bit Size: .0289 If using autopass or BenchPilot, I like four passes, including a roughing pass. Just trying to be gentle with these parts. Make a second outside cut with .01 offset. Same depth and bit size. You can cut this to full depth on a single pass, no roughing. Replace the tapered bit with a 1/8th bit. You can use an automatic Z-touch. Don’t forget to change the bit size to 1/8th. Import each of the “pocket” files, and place them by snapping to the same spots as the taper files. Pocket using the following exact settings: Depth: .15 Offset: .017 Bit Size: 1/8th THE OFFSET IS CRITICAL. If you don’t offset you’ll wreck the walls you cut with the tapered bit. I like 2 passes for the pockets. If using BenchPilot, you don’t have to follow up with an inside cut. If no BP, make an inside cut (yes, inside) using the following settings: Depth: .15 Offset: .017 Bit size: 1/8th 2 passes, no roughing pass. Why is this an inside cut when the tapered bit cut was an outside cut? Its because the “pocket” files were shape shifted to combine the inlay part with a bounding box. You are cutting inside the bounding box. UPDATE: Halfway through another inlay project, it dawned on my slow and ancient brain that I don’t need a full pocket for the male parts. I just need to clear enough around each part to use a bandsaw to separate each part from the other parts. So now I’m just using the "taper" file to cut both the taper and an outside cut with a straight bit. If I need more room around a part I do a second cut with the straight bit, adding some offset. For get the pocket file, you don't need it. Making the parts this way takes a little more time at the bandsaw because the cuts can be irregular, but overall its much faster: (1) no need to align a pocket file with a taper file, and (2) an outside cut is a lot faster than a pocket. Remove the part/MDF sandwich from WS. Keep the parts attached to the MDF, but cut each part/MDF sandwich to separate all the male part/MDF sandwiches. Now for the females. Mount the trivet to WS using the inlay shelf (or your substitute). Level it (using the wonderful WS leg is best). As the production proceeds you will need to remove the trivet from WS and remount it to EXACTLY the same spot on WS. The ability to remount in exactly the same spot is what makes intricate inlay details possible. You need a solution like my inlay shelf or your own substitute. Related to that, I don’t recommend double sided tape for mounting. If you use double sided tape you risk moving the WS shelf as you remove and remount the trivet. Scan and grid. If you want to place the inlay exactly as designed, you’ll want to probe the edges of the trivet for your grid. But it’s OK to eyeball it if you don’t care about exact placement. Import and place the female file. Mount the tapered inlay bit, and do a super careful and accurate manual Z-touch. Remember: an accurate Z touch is mandatory for good results. The female file has five components: Rear shadow, main leaf, stem shadow, tip shadow and stem. We are going to cut the female for one component, remove the trivet from WS, glue in the male for that component, let the glue dry, sand the male flush, then return the trivet to WS for the next component. The components have to be done in this order: (1) Rear shadow (2) Main leaf (3) Tip shadow and stem shadow (you can save time by doing these two parts in a single stage) (4) Stem. The female recesses (other than the main leaf) are small enough that we will cut the entire female recess with the tapered bit. So for the rear shadow, pocket cut using the following settings: Depth: .12 NOTE: the depth for the females is not the same as for the males. Offset: 0 Bit size: .0418 NOTE: the bit size for the females is not the same as for the males. The worksheet has these settings. If using BenchPilot, I like four passes, including a roughing pass. Again, tryng to be gentle. If using BenchPilot, a pocket is all you need. If no BP, then follow the pocket with an inside cut and these settings: Depth: .12 Offset: 0 Bit size:.0418 If you don’t have BP then you might want to cut the pocket in fewer passes to save time. Maybe two or even one pass. For the inside cut I’d recommend four passes, including a roughing pass. When you are done with the rear shadow female, remove the trivet from WS. DON’T MOVE THE SHELF! Glue and clamp the male rear shadow/MDF sandwich in place. It’s helpful to remove the clamp after about a half-hour, but not necessary. Even if you remove the clamp, leave the part/MDF sandwich in place long enough for the glue to dry (about 4 hours here in low humidity Colorado). When dry, carefully pry the MDF from the part. This is why its helpful to remove the clamp after 30 minutes — the longer the clamp stays, the stickier the tape. Sand the part flush. I use a drum sander but if you don’t have one, use a ROS. You can use coarse grit — just need level, not smooth. Mount the trivet back into WS in exactly the same spot. (This is why you don’t move the shelf.) Make an inside cut on the main leaf, using the tapered bit and the following settings: Depth: .12 Offset: 0 Bit Size: .0418 Make a second inside cut on the main leaf with the tapered bit, using the following settings: Depth: .12 Offset: .01 Bit Size: ,0418 Switch to the 1/8th bit. Z touch. Pocket the main leaf using the following settings: Depth: .12 Offset: .023 Bit Size: 1/8th One pass is fine for this. If using BenchPilot, no need for an inside cut. If not using BP, make an inside cut using the following settings: Depth .12 Offset: .023 Bit size: 1/8th One pass is fine. When the main leaf female is done, remove the trivet from WS, and follow the same procedure as for the rear shadow to glue in the main leaf. When done (glue dry, sanded flush) return the trivet to WS. At the next step you can mill the females for the stem shadow and tip shadow. Same process as for the rear shadow — the entire females for these will be cut using only the tapered bit. When the females are done, glue in the stem shadow and tip shadow part/MDF sandwiches (you can do both at once), let them dry, sand flush and return to WS. The female for the stem is cut the same as the stem shadow and tip shadow. When the female is done, glue in the stem part/mdf sandwich. When dry, you are ready for final smooth sanding and finishing. I ordered some silicone feet for mine. That’s optional. I finished mine with Howard’s Butcher Block Conditioner. Easy to find in most hardware stores. This guy sells nice silicone cutting board feet if you want to add those: https://cuttingboardfeet.com/ Hope you have fun with this.