This Router Machine can hold a flexible Dremel tool or A Foredom General-Purpose Flex Shaft Rotary Tool - H.44T . This allows for 1/4 inch or 6.25 mm router bits.

Quite a few parts get used in more than one place . Part 16 ,15 and 12 are good examples of how a parts duplicate is used across the machine. There are lots of less obvious examples as well parts 58 60 36 39 51 52 22 and 4 , are all redundant parts that get used in multiple places . I've built 2 Machines like this now and I have the assembly time down to around 15 hours . This is not including printing time just part post processing and assembly . There is only a need for part 46 , 47 and 53 if you Have a Dremel flex shaft . If your going to use a Vevor Flex shaft Mill you don’t need to print them. Instead print 53.1 and a quantity of 2 of 46.1

The machine has 12 mm diameter rods for slides on the x and y axes. I purchased a Befenybay 200mm 4080U Z-axis Screw Linear Actuator for the z axis from amazon.

A slight modification was done to this z axes .I took out its adjusting cams and reinstalled them on the front of the z axes slide plate rather then leaving them on the back this allows for much simplified adjustment. I've only tested that modification on the Foredom flex shaft Mill . It has not been attempted on the Dremel version .

The stepper motors and the anti-backlash nuts are attached with m3 threaded rods and nuts. The threaded rod goes all the way thru the part and gets double nutted on each end with a lock washer . I cut the M3 threaded rods from 150 mm long m3 threaded stock to the proper length. Then I saved the cutoffs for parts that required a shorter length threaded rod. Anywhere that I’m not bolting all the way through a part, I'm likely using one of those brass threaded inserts that can get melted into the part. Its with the stepper motors that special care should be taken in taking only one bolt out at a time so as to avoid separating the armature from the rotor. This prevents loss of the thrust washer and also introduction of foreign material to the magnetic parts
Opposite the X and Y axes stepper motors on the 8mm linear drive/Acme screw is a thrust bearing setup and printed thrust bearing cartridge. This cartridge allows you to set the backlash for that axis. I printed part 31 and 32 with 100 percent fill and sanded the face of it a little at a time until I had the desired backlash. Part 31 and 32 are the parts that actually determine the amount of backlash.

Part 39 is a bearing race holder. The bearing race is a suitable washer that fits tightly into part 39. With the washer in there, I sanded the part until the washer was shiny and flush with the plastic edge.

Part 36 is the inside race holder. It also gets a washer and gets sanded also, but it slides onto the acme lead screw and fits tight onto a shaft collar. The set screw on the collar sticks out a little and there is a little notch in the part to accommodate that set screw. See the 7th photo. It shows part 39 on the left side of the picture and two of part 36 facing away from each other on the right side of the photo. There is another part 39 off to the right that can’t be seen . It's these parts 31 or 32 and 36 and 39 that make up the backlash cartridge. They all sandwich together and 4 M3 threaded rods keep everything tight together. If you assemble the end opposite the stepper motor and there is no backlash then you need to sand part 31 or part 32 some more . You can stop sanding it when you assemble it and you can detect a little backlash. 0.001 inch (.254mm) is good .Some backlash is necessary so the bearings wont wear . The face that you need to sand is the face that was up when you printed it. I’m using regular steel m3 nuts and stainless threaded rod so the nut will just crack if you over tighten it. The nut will continue to tighten without a reduction in backlash if its tight enough. End play is being checked as I’m tightening the nuts .This is done using part 28 . .

To check the tolerances, part 28 is the backlash/dial indicator tool holder tool(9th Photo). Assembly order is first set backlash at one end, and then install the stepper motor at the other end of the lead screw . Then measure to determine the desired length of 12 mm Rod. Remove the backlash cartridge and stepper motor to prevent damage after the measurement has been taken . Install the 12 mm rods with bar clamps. Parallel bar clamps are what I used used to press the 12 mm rods into their respective parts. (Sixth photo) . Finally reinstall the backlash cartridge and then stepper motor again after all linear rods are installed on the Machine . The couplers joining stepper motors to acme screw rods are the two piece type . Originally I used single piece couplers and the printed parts have little access holes to get an allen wrench thru this works but it's much easier to assemble with 2 piece couplers . Hindsight is 2020 use 2 piece couplers.

I'm using LM12utu bushings throughout..Sleeves (Part 27 ,29 and 30) hold the bushings and then the sleeves slide into their respective parts. This makes sanding to a perfect fit a little easier. It's easier to sand the outside of the sleeves then the inside of the holes they slide into. You do have to sand the inside surfaces a little. Initially the bushings will get stuck. its when the sleves are sanded to the perfect diameter that the 12 mm rods slide smoothly . I recommend first getting the x axes assembled and The Z carriage sliding back and forth by hand ( clamp both part 16s to a table or flat surface as your doing this ) The 2 y axes sides get assembled thru the bushings in the x axes second. Get the right and left side sliding back and forth individually before you attempt to get them sliding simultaneously . When it comes time to secure the y axes to the 2o by 2o rails ,use part 28 again, the backlash indicator holder tool .This time use it to make sure y axes rails are parallel . The machine should be able to travel from y minimum to y maximum without a change in reading on the runout gauge connected to the end of the x axes drive screw (9th Photo) . That is how you know your Y sides are parallel. ( End play/backlash is being checked at many spots along the y axes and at both ends .It should always be the same ) I’m using a standard CNC shield. It allows for limit switches . Here is the switch type I used (10 x Mechanical Endstop Limit Switch End Stop with 22AWG Cable for RAMPS 1.4 3D Print Limit Switch). The x and y axis limit switches are double ended. They trip at the x minimum and x maximum. There is just one switch. However, it is activated at both ends of travel. Part 57 is a spring seat for the double the ended limit switch. The springs on the double ended limit switches are the same springs as on the anti-backlash nuts. I just cut them a little shorter to make them fit. Ideal spring length is found by gradually shortening until the valley between the bumps on part 58 is lined up with the bump on the switch lever arm (10th Photo) . A 3 mm threaded rod goes all the way threw part 58 and part 60 screws onto each end of it . The 19th photo shows a double ended Limit switch that I remixed/redesigned its a little better in my opinion but doesn't have a lot of hours on it yet.You can check that one out as well . The LEDs on the limit switches boards work. I power them with the 3.3 volt supply on the CNC shield and ground. The voltage is always there and if a switch or a wire develops an open, it will trigger an alarm at the CNC shield. See the 4th photo schematic The 2n2222 transistors invert the limit switch signal. Each z limit switch connects to an optical isolator input just like the x and y. The Z axis signals from each optical isolator connect to a diode XNOR gate (Schottky diodes are used here ). The XNOR gate output signal connects to a 2n2222 transistor. I'm using 2 separate z limit switches as this allows a little greater X axis travel distance. I transition from 3.3 to 5 volts on the optical isolator board . . I don’t recommend running without an optical isolator . Its voltage dividers are handling the voltage increase but it is also preventing stepper motor noise that would result in false triggering. This is the Type I used ( NOYITO 4-Channel Optocoupler Photoelectric Isolator Module Level Voltage Converter Module PLC Signal Converter Module PNP NPN to pnp (3.3V to 5V) again from amazon ) The X and Z limit switches share the same power and ground thru the cabling tracks. It’s only there switched output that needs to be kept independent.

Part 20.1 and part 20.2 are stops for the limit switch to run into . There used on the Y axes only. Part 60 contacts them .You may discover you like part 20.2 more than 20.1 as its shape is improved and guarantees your cable track won't snag it.

I have several vacuum parts not all vacuum parts seem to work well with all types of router bits and projects . Dremel uses 1/ 8th inch bits and some vacuum parts are designed for 1/8th inch bits. Others are for 1/4th inch bits. Very little vacuum is needed if you are making a pc board. Other vacuum parts are designed for maximum depth and large air flow. You can adjust the machine to cut deep by loosening the bolts in part 42 and sliding the entire z axes lower. Included are 3 types of vacuum attachments . Any of which get glued together and then installed into part 50 or 50.1 or 50.2 .
Printing part 50 is no longer necessary as part 50.1 works with both Dremel and Vevor Hanging Flex shaft Mill and part 50 only works with Dremel. However part 50.1 is larger. Part 50.2 is a part that can be printed on a small printer . it works with dremel and flex shaft mill. It may be the best yet. Finally regarding vacuum attachments please see also . The thing called Vacuum attachment Hot Tub CNC Machine for additional ideas and files. Part 16 has surrounding attachments designed to conceal wire and hold cable tracks ( photo 15) . I used 22 awg stranded wire for everything in the cable tracks. Each wire is given a number at both ends to assist with identification . It then gets soldered directly to the wires coming out of the stepper motors and the limit switches. At the top of the z axes is part 2, a box ,that secures to the back side of the z axes,. It's provided to wrap up a little extra slack in the wiring so that if I need to resolder a wire , replace a motor or a switch I will have the necessary length to service and troubleshoot without running a whole new wire . At the other end of the wires below part 21 and 35 there is some room to hide a little slack in the wires for your splicing and troubleshooting needs. . There is enough room to run several extra wires in the cable tracks if you stagger splices just a little .I ran 5 extra and labeled them on each end .
Most parts should be prinable on a 6 inch prusa. The Uno/cnc shield shield base (part 24)is a bit big. The wire guide on the side of it can be eliminated if your print space is limited .That is why you see 2 of them 24.1 and 24.2 . On the z axes each side has part 52. A z axes limit switch holder .Its held down with m5 bolts about .46 inch long and the limit switches bolt to it with m3 bolts and nuts these bolts mustn't be too long . The switch has a cover, part 51 and its bolts must not be too long also. I had to dress them with a file so part 52 would sit flat on the surface its bolted to. I’ve done a dozen carvings in hardwood and 2 in aluminum with this machine. So far, the machine seems to work excellent. Its strong enough to last. Cutting area is 335 by 335 mm (13" by 13"when I back 4mm off the limit switches (a setting in the GRBL firmware). Larger cutting areas are possible with these same components .The machine is extremely accurate but you would definitely sacrifice accuracy if you built it larger than 2 foot by 2 foot . Mainly do to the 12 mm slides . I placed a spoil board on top of the 20 by 20 rails that can be removed . When the machine is complete you can use it to locate and countersink 4 holes in the spoil board for some m5 bolts to hold it down . M5 bolts hold the 4 corners of the machine to the 2o 2o rails .If these M5 bolts are giving you difficulty you can use M5 studs and install nuts and lock washers on the studs. Lock washers are in use everywhere on this Machine . M4 Bolts hold down tools and vacuum parts . M3 is used for cable track securing and the anti backlash nuts . anything not otherwise mentioned is either M3 or a small Screw.

It so far has the accuracy of an inkjet printer and the strength of an arbor press. I’m very pleased with the first projects I’ve completed with it.