Bosch Bench Router Table Insert RA1181 or RA1171 STEP 3MF FreeCAD

Description

So here are the details about accuracy and what you need if you want to modify anything here. I have included my FreeCAD file (version 0.20 (27008)) with parametric Part Design WB parts. I have uploaded error free meshed files, the STEP files for easy editing in any CAD software, and a PrusaSlicer generated 3MF file (MK3S+/0.6mm nozzle/PLA - all of which you can change after opening) that will work as a baseline in any slicer software. All parts that require printing multiple quantities have the number at the end of the part name. Documenting and writting this took as long as the project itself, it was probably a total waste of my time, maybe yours, but hopefully someone finds this useful or interesting. If so, please let me know by liking, commenting or posting makes. That's why I took the time to post this. The manufacturing tolerances of the Bosch router mounting plate insert appear to be around +/-1mm or larger :-(seriously). The hole diameters and placements seem to have around this level of error. I corrected a few spots in my model that were very close to the same measurement, but not all. It is difficult to determine what differences are intentional offsets and what is tolerance error when I do not have the tools that mount in these positions. I can say, the screws that hold my router base to the insert plate fit well, but are not all centered in the flange holes of the insert plate after tightening. So, how good is this CAD model of the insert plate, and what should I expect? Useful but not perfect. First for clarity, I will call the long edge of the insert plate opposite from the 'Rotation' label and arrow "Top" and the center of this edge "12 o'clock." All of the router mounting holes were constrained the same way. The easiest router mounting hole to first constrain was the small mounting hole at 12 o'clock. This is one of the holes used to mount a Bosch 1617 fixed router base (RA1161 / what I have). I measured this hole to confirm it is centered between both sides of the plate. Then I measured the distance to the cutter hole internal diameter. The RA1161 base has an equilateral triangle mounting hole pattern which I used to fully constrain all three of these holes on the insert plate. All other router mounting holes are constrained using the distance to one of these three RA1161 base mounting holes and the distance to the center cutter hole ID. In FreeCAD all parts are made in the Part Design work bench. I also made a spreadsheet with a single variable used for all of the filler parts. This variable sets the clearance around all parts. Each individual filler part has a binder reference to the insert plate model and the spreadsheet variable is used to set the clearances. If you need to make adjustments to the overall X and Y dimensions, editing this variable will adjust the clearance without impacting the small lip designed to fit the chamfer of each hole. If you need to edit or correct something it is probably better to edit the insert plate model instead of the filler parts. Also note, the oval holes are different sizes, are deeper than the other holes, and do not have a chamfer. I think the differences in these shapes are intentional, and are probably the same on all of these insert plates as they appear to be cut on a CNC mill. This is where my earlier mentioned clock reference scheme is important. All four of the oval holes have unique inserts made. The files are named with clock positions. It is easy to get the parts mixed up and fit the wrong part in the wrong hole. It may be a good idea to print these separate and locate them in a way that makes sense. As pictured after mounting in the table, I decided to leave off the caps for the four outer mounting bolts that retain the insert plate. I used a small dot of hot-glue to hold down all of the fillers. Yes PLA and hot-glue work well together. Just try it. It is possible to remove the fillers from the top after gluing them in but it is not fun and risks marring the aluminum surface. This is why I left the four mounting screw holes without inserts. In the worst case, if I need to remove a filler insert, I can take everything apart and knock out the filler from the back side of the insert plate. Before glue, all of my inserts fit below the top surface of the insert plate. I printed these in cheap red PLA because I was too lazy to change filament, and red shows up on camera. I think PLA is fine for this, but I will probably reprint these in clear PETG at some point because clear PETG is practically camouflage texture for aluminum surfaces, and why highlight the hideous utilitarian look of the plate with bright colors. Major Aside... The Bosch RA1181 Router Table and old Contractor Tablesaws. Maybe you noticed, but my RA1181 is mounted on a 10in Craftsman 315 contractor's tablesaw. The Bosch RA1181 bench top router table is 27in wide (the cheaper RA1171 is not). If you can find an original Craftsman iron router table leaf for these saws, definitely go with that. It is the BEST cheap-ish option if it can be sourced for less than ~$200. You will probably discover that the Bosch cast aluminum insert plate of the bench top router tables is not straight. You may discover an unexpected reason why this insert plate comes with four retaining fasteners with six additional fasteners used to adjust the insert plate tram height. At least on my plate it is slightly bowed diagonally. While usable, it is impossible to get one of the four corners (of my choosing) to sit completely flush with the other three. (I use a 1-2-3 block to check if it catches the edge of the plate or rocks while straddling the table and insert plate.) The merits of aluminum machined surfaces aside, the Bosch RA1181 is almost a perfect drop in fit on any tablesaw with 27in depth. All I did was drill and tap a few holes in the flange lip of the iron saw top using holes already existing in the RA1181. This is super easy to do. Cast iron takes a tap like butter. The holes in the RA1181 do not interfere with the original stamped steel extension-leaf mounting holes in the tablesaw, so the mod is fully reversible. The RA1181 even has slots built into the side flanges of the aluminum table that work perfect with the T-bolts in the Align-A-Rip (fence) aluminum extrusions. These side slots make it super easy to sit the table in place on the rails while holding the aluminum surface just below the iron tablesaw top. This makes it really easy to get it level with the tablesaw top. It is actually easier to level the RA1181 than it is to level the original Craftsman stamped steel sheet metal leaves. No joke. I just drilled and tapped 3 holes, and this was overkill as a simple hole and hex hut would have worked too. IIRC, there is interference with the reverse operation of mapping the holes from the tablesaw leaf to the RA1181 flange. One (or more) holes intersected slots in the aluminum flange. Overall, if you already have the saw, this is like an accessory that is still retail available. I'm not the first to do this mod, but I did not find much info about it when researching, so thought I might mention it. -Jake

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