I got some inspiration to make some end covers for the stepper motors based on these that are available all over the place like here from Cnc4pc.
The ones for sale are for smaller Nema 23 steppers with 56.4mm frames but I needed some for the bigger 60mm framed nema 23 570 oz/in steppers.
A few other sizes have the same larger frame, 425 and 495 oz/in'ers for example.
I put my 3D Printer to work to make these for myself very quickly and easily.
I made a left hand side and right hand side versions so the motor cable goes out the back.
They could just as easy be made with the cable going out the bottom too.
I used these XLR connectors from keling.
The covers are mounted using the M3 threaded holes in the stepper used by the long stepper frame screws themselves. Clearance needs made to have enough threads for the cover screws. Take one screw out of the stepper and cut/grind off about 1/8th inch then replace the screw then continue with the next screw. Don't take them all out at once.
I got some 3mm x 30mm stainless machine screws from mcmaster.com part# 92000A132.
They need an 1/8th cut off too. Seal the cover up with some RTV gasket sealant.
The Power Drawbar 3 was created after a cnczone member combined my previous power drawbars for inspiration into one that used a cam lever and the floating design to get max force but from a cheaper easier to find single stage air cylinder. A great idea I had to copy. :-) I basically used the cam lever section like from my power drawbar for the X2 and the floating base design from my PDB2 for the G0704 with some improvements. Initial tests are good and it puts out a lot of force. On paper it should provide 2000 lbs with a 2.5 in. bore cylinder and 3000 lbs. from a 3 in. bore cylinder at only 80 psi. Most home shop compressors that max at 125 psi will cycle down to around 80-85 psi before they kick back on so that is where you should have the tension set on your belleville stack to release the tool so it will always release. Some compressors allow you to adjust the pressure switch cut in pressure so you can make your minimum higher and therfore get more from the PDB. At 100 psi a 2.5 in. bore could give 2500 lbs and a 3 in. bore, 3600 lbs. There are videos on youtube on adjusting the pressure switch. I made some prototypes with my 3D printer designing this and you can see them on my youtube channel, search for PDB 3. Ebay is a good source for cheap air cylinders, a 2.5 in.(63mm) bore, 4 in.(100mm) stroke, double acting is the mimimum recommended, a Fabco G-521-X fits the bill and pop up a bit.
You can request the free plans, contact me at hoss@g0704.com.
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