Myford Super 7 车床tachometer安装支架

The design is built around the generic 8-24VDC tachometer unit. This consists of the control unit with display, cabling and a hall effect sensor. The sensor body is approximately 12mm in diameter and comes with two flat nuts and two locking washers.

The mount consists of eight 3d printed parts. Apart from the Tachometer, you will also need to source the following:

• a small flat round magnet (approx 10mm x 3mm)
• a flat steel washer (approx ID 13mm OD 24mm). You could use the spare locking washer (only one is needed), but I haven't tried this.
• 10 x round head self tapping screws (2mm)

You will need to prepare the cabling for the unit and sensor. I cut and re-joined mine to eliminate the excess cable. The DC feed and connection are housed in the Box for tidiness.

You may also need to relieve some of the holes. I used a 12mm reamer for the sensor holes.

1. Spindle ring. This holds the magnet for the hall effect sensor. This slips over the spindle locking collar and has a relief for the cap head bolt. I wrapped a piece of electrical tape around the circumference to trap the magnet and secure the ring.

2. Lower nut holder. This holds the lower sensor nut captive and is shaped to fit inside the top of the cover.

3. Base. This incorporates the upper sensor holder. The top sensor washer and nut trap this between the two nuts and the cover. It is shaped to fit over the asymmetrical arched top of the gear cover.

4. Base lid. This fits over the base and has a relief for a large flat steel washer. A round magnet is glued into the Box Bracket to support the Tachometer box.

5. Box bracket. This supports the Tachometer mounting box. It incorporates a hole to locate the sensor though and a relief hole in the bottom to locate a magnet.

6. Box. This holds the tachometer unit. I used two short self tapping screws to secure the unit. The screws do not interfere with the electronics inside.

7. Box back plate. This screws to the back and to the bracket. A cut-out in the Box allows you to feed the wiring to the unit.

8. Box Logo. This screws to the lower front of the Box and is entirely decorative. I hand painted my one.

Assembly.

1. Fit the Tachometer control unit to the Box and secure with two screws into the unit avoiding any electronics.

2. Fit the large steel washer to the relief in the base lid and secure with glue (e.g. epoxy).

3. Fit the small magnet to the bottom of the box bracket and secure with glue (e.g. epoxy).

4. Locate the tachometer sensor magnet into the hole in the spindle ring and clip the ring over the spindle collar. Run a piece of electrical tape around the circumference of the ring to secure.

5. Press one of the two flat nuts from the sensor into the relief in the lower nut holder.

6. Position the lower nut holder inside the gear cover top and passing the sensor body through the hole, screw it in a few turns until the sensor is just below the holder. Note, the nut holder is asymmetrically curved at the top so only goes one way. Close the gear cover and holding the sensor (attached to the nut holder) up to check it doesn't foul the spindle ring. Adjust as necessary for the correct operating clearance.

7. Feed the cabling from the sensor with the plug and DC feed from the bottom through the base (from below) then through the locking washer, then the flat nut.

8. Position the base over the gear cover and pull the sensor up through the hole and lock it in place with the lock washer and nut. Note that the arch in the base is also asymmetrical so only fits one way.

9. Feed the ribbon cable and DC feed through the box bracket and ribbon cable through the box back plate in that order.

10. Connect the cable and DC feed and tuck inside the control box. Fit the box back plate tucking the DC feed wiring through the cut out on the box.

11. Fix the bracket to the back plate using two 2mm screws.

12. The bracket sits over the sensor on the steel washer and the magnet holds it in place.

I used CorelDRAW to create the asymmetrically shaped arch for the base and nut holder. I did this by tracing an end photo of the gear cover. I exported this as a SVG file. I also exported a tracing of the Myford logo in SVG format.

I then used Tinkercad to create the different components, importing the SVG files and exporting for slicing as STL file.