Build Thread - Chevalier 2040 CNC Bed Mill

[Coolidge62]

With the encoder on motor, you will not be able to do peck tapping. You need the encoder on the spindle to give exactly one index pulse per spindle rev in order to be able to retap the same hole.

The motor and spindle turn at the same RPM. 500rpm on the motor = 500rpm on the spindle. It's a 1 to 1 ratio.

That might be ok if there is no lash in the drivetrain to the spindle.

Better solution is the encoder directly connected to the spindle.

Uwe

Power is transferred via a 30mm timing belt and B&B Manufacturing timing belt pulleys. Brand new spindle gear hub so zero lash with the spindle pulley hub. That also tightened up the spindle gear hub to splined spindle. Of course new bearings throughout including P4 angular contact bearings. It's as tight as she's ever going to be!

[Coolidge62]

For that you will likely need the low ratio, at which point the motor encoder isn't 1:1.

Exactly, the double reduction low speed range will grunt through whatever I will tap with the 5hp motor. And again, someone quite knowledgeable on the subject described DUAL inputs for RPM. I haven't fully unpacked his post but it sounds like it's possible to config for the low speed range. Once the reduction is calculated it's simple math motor RPM vs spindle RPM in the low speed range.

[Coolidge62]

After an epic 7 hour battle I wrestled the 6,000 lb thing into it's final position. 90 degree turn, uphill a few feet, over a few feet. The pallet jack lifted it but I couldn't budge it. A mix of pushing with the tractor as far as I could get it them pulling with ratchet straps anchored to the tractor and lathe. Phew!

Now clear of the garage door and in it's permanent home I can install the Z servo, head and get the new shop lights hung.

[tblough]

Exactly, the double reduction low speed range will grunt through whatever I will tap with the 5hp motor. And again, someone quite knowledgeable on the subject described DUAL inputs for RPM. I haven't fully unpacked his post but it sounds like it's possible to config for the low speed range. Once the reduction is calculated it's simple math motor RPM vs spindle RPM in the low speed range.

That's correct, you will be able to rigid tap in low range, but you will not be able to peck tap in low range.

[suntravel]

Exactly, the double reduction low speed range will grunt through whatever I will tap with the 5hp motor. And again, someone quite knowledgeable on the subject described DUAL inputs for RPM. I haven't fully unpacked his post but it sounds like it's possible to config for the low speed range. Once the reduction is calculated it's simple math motor RPM vs spindle RPM in the low speed range.

That's correct, you will be able to rigid tap in low range, but you will not be able to peck tap in low range.

Also no way to do a second rigid tap if depth of the first one was not ok...

Uwe

[Coolidge62]

Guys, here's the filth bath the spindle gear hub lives in. If there's another location to install on the spindle I'm all ears. It's not a capability if it's not reliable and requires half the head to be ripped apart to fix it. As far as I can see the only reasonable location would be to attach to the spindle nose piece and encase in some kind of sealed armor.

[tblough]

Well, it looks like you are out of luck then. If you examine the exploded views of the Bridgeport head 2J head, the only place you can get 1:1 with the spindle is below the transmission where I installed my encoder. Luckily where the feed worm is located is not near as dirty as the upper transmission and my encoders have been working 5+ years on 3 machines.

I'll be interested to see your spindle nose solution.

[Coolidge62]

I'll be interested to see your spindle nose solution.

There's almost 5/8 inch of spindle nose piece (the threaded collar that holds the spindle in the quill) to clamp onto so plenty of meat to work with to clamp a sensor onto. The bottom of the spindle has 4 large 10mm tapped holes. No doubt used in manufacturing the spindle as they serve no other purpose and are partially covered up by tool holders. But there's about 70% of those holes open outside the diameter of the NMTB 40# taper tool holders. All sorts of options there for mounting a spinning sensor trigger. Could make a tapped plug and insert a iron rod like I see the Extech tachometers use. For that matter 4 tapped plugs to mount a spinning ring of sorts.

It would need to be sealed against oil, coolant, flying chips but this area is several inches above the cutting tool tips. I think this area is the best option for retrieving the actual spindle RPM or position.

[Coolidge62]

Finished the CAD on the 5/8-11 drawbar and ordered a whole Maxi Torque-Rite power drawbar today with a new drawbar. The mill had a hack job Kurt power drawbar on it when I got it, missing parts and malfunctioning. The drawbar was also way too long and the brass spacer destroyed because it would bottom out in some tool holders. So I had to measure everything to determine the proper drawbar length, spacer etc.

I also completed phase 1 of the American Rotary phase converter install. Assembled. This is the 15hp ADX. Had to get the engine hoist out to lift that idler dang!

I fixed Baldor's stupid screw up. Also fixed American Rotary's stupid cheap out. Next bringing in the single phase power and running 3ph conduit out to the machine.

Details: The phase converter bolts to the idler motor via idler motor studs that stick out each end. American Rotary includes some slim nylock nuts to attach the mounting brackets. Baldor idiots stuck a mile of threads out one end of the motor, like 2 inches and almost none out the other end of the idler. Even the slim nylock nut would only grab about 2 threads and not even touch the nylon. American Rotary for their part of this nonsense gave you a hex nut to use as a spacer so the bracket would clear the idler end bell. Really, why not spend $1.25 for an actual spacer?

Fortunately I had some slimmer 1/8 inch thick stainless spacers on hand. That freed up some threads. Their slim nylock still looked sketchy so I used some stainless wizz type lock nuts I had instead. Problem solved but kind of lame for a $2,000 product.

The American Rotary phase converter is otherwise a work of art!

[Coolidge62]

Gathered the parts for the lower spindle gear hub assembly

Done!

Installed the low speed range small gear.

Gathered parts for the upper spindle pulley hub, spindle brake, timing belt/gears assembly

Installed the spindle bearing, brake shoes and brake actuator.

Installed the spindle pulley hub and timing belt pulley. This is the lower half of the old variable speed belt drive system. It's only purpose now is to be a brake drum since I am converting to direct timing belt drive and a VFD driven inverter.

Completed assembly of the 'pancake housing'. This sandwiches between the lower spindle assembly and the top casting which holds the spindle motor.

Test fit the adapter plate for the Black Max 5hp inverter spindle motor. I had Front Panel Express make this for me on a CNC machine.