# Clausing 5914 VFD



## machPete99

I did this a while back, but figured I'd post the info for others that might be interested.

This setup completely replaces the original Reeves drive and countershaft arrangement. The motor is the original Doerr 2HP 3PH unit. I am using the stock cogged belt size/length, but have fitted the motor with a slightly smaller drive pulley (22T). I redrilled the motor support brackets so they could use the slots previously used for the countershaft support. A piece of 1/2" steel plate is used to get the motor in the correct location, in line with the spindle pulley.

Mechanical parts, from McMaster-Carr:
6495K615 - H Series Quick Disconnect Timing Pulley (1-1/2" wide H series Quick Disconnect 22T)
6086K34  - Quick Disconnect SD 7/8" ID 3/16" keyway
6484K284 - H Series 63" x 1-1/2" Belt (630H150)
99020A420 - 3/16" key stock

VFD is Hitachi WJ200-022SF, from Drive Warehouse. I am using  4 x 50 ohm 100 watt resistors (in series/parallel pairs for 100 ohm total) for braking. Most of the control items are from Automation Direct.  The enclosure is good sized (14 x 12 x 8), from factorymation, so does not need a separate fan. I am using a (2) pole motor switch as a disconnect, relatively simple control wiring. The original motor flexible conduit has been rerouted to enter the enclosure, near the top. Everything is mounted to a an aluminum plate which can be removed for service.

The speed control is pricey but industrial quality  (Allied:  Honeywell 53C11K + Schneider Electric ZB4BD922). The control panel is located where you stand so you can change speed etc. while machining.

Pete


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## wa5cab

Another member here inherited a 6900 Series on which he says the variable speed drive had been disabled and a VFD added, possibly with the original motor.  He hasn't taken any photographs yet so I don't know exactly what was done to it.  It is difficult to judge from your one photo how high your motor is off of the floor.  Is it located approximately where the countershaft once was?  Maybe that's what was done to his.

Over what motor RPM range (slowest to fastest) do you run the motor?  And whatever the slowest speed is, have you noticed any tendency to overheat after running for an hour or more at that speed?


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## machPete99

The top of the 1/2" motor mounting plate (bottom of motor flange) measures about 15-1/4" from the bottom of the housing.
Motor centerline is approximately at the centerline where the countershaft would be. Its actually slightly lower due to the slightly smaller pulley.

From my calculations, speed range is similar to what the Reeves would do, if allowing motor to go from 24-120 Hz (696 - 3480 RPM):
Direct drive: 388 - 1940 RPM, Back Gears: 55 - 277 RPM

Any slow turning I tend to use the back gear mode, so motor is turning relatively fast. I have not seen any overheating issues. The only issue I have is that using too much brake at higher speeds with a large (8") chuck can cause the control to kick out. My "brake" knob simply changes the braking constant for quicker stops, but needs to be used at lower speeds. All of these settings are adjustable on this VFD.

I was able to drill 1" holes in a couple 3/8" thick steal disks recently without any trouble (in back gear), no shortage of torque for "normal" tasks. This VFD does have some special settings ("Sensorless Vector", "Torque Boost") that are supposed to produce more torque at lower RPMs, and I do have them enabled.

The "Jog" mode is really the same as setting the motor to a slow, fixed speed (currently 6 Hz or 174 motor RPM, 14 backgear spindle RPM). Its probably best for things like powered tapping, but I have not used it yet. You probably don't want to run at that speed continuously.

You can reverse the motor while running, although it goes through standard deceleration and acceleration rampings.


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## wa5cab

OK.  That sounds encouraging.  

What size is the 5914?


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## machPete99

The 5914 can swing 12" over the carriage, 36" between centers, weighs about 1100 pounds or so (maybe less now, without the countershaft stuff). Spindle has 1-3/8" bore, can take 5c collets with proper adapter sleeve. Ways are hardened on this lathe, cannot detect discernible wear on mine.

Mine is mid 70s vintage. I had to replace bearings in the motor, back gear (drive hub) and quick change gearbox. Everything else is just cleaned up a bit. The countershaft clutch mechanism has at least one oddball bearing that you might not be able to easily find. I did have to make sleeves for some of the bearings as current sizes differ on the ID a bit.


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## wa5cab

OK.  What's the swing over the bed, and the nominal distance between centers?


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## chips&more

How smooth running is the new conversion? Are you getting any noise in the finish of your cuts? Do you miss the clutch?


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## machPete99

I did not run the lathe much in its original configuration, except at the shop that I bought it from, so cannot compare much on finish. The lathe seems to run very smooth, especially in direct drive. It is also much quieter now; the Reeves setup made a lot of rumbling noise. There is a small amount of whine from the VFD but not objectionable. Noise now is predominately from the gear train, when in back gear, or running the lead screw. I ended up adjusting the banjo position for better engagement and that also quieted things down a bit. I would not have been able to hear that issue over the Reeves rumble.

The VFD has electronic braking which I think is similar to the mechanical clutch/brake capability, and you can also adjust it, within some amount of reason. I don't really miss the original clutch, and it had some issues (would not stay engaged). It might have been nice to rig a another stop switch to the original clutch/brake lever but I did not bother (at least yet). Having the handle at the carriage is a nice feature, but I arranged to have the control buttons in close proximity.

Being able to change speed in the middle of a cut is a nice feature. You can dial in the color of the chips. The original Reeves control on this lathe is not really in a very good location.


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## machPete99

Attached is a recent project, flanges for a tractor loader support. These were made from DOM tubing, OD turned down, and CRS flanges, tigged on and then trued up on the lathe. I think this was all using HHS tooling (MO Max), in back gear. Finish was not super important, so probably cut a bit aggressively. No noise in the cut here, and these are tough materials. The pits on one of the flanges is the weld area.


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## Dhector

wa5cab said:


> Another member here inherited a 6900 Series on which he says the variable speed drive had been disabled and a VFD added, possibly with the original motor.  He hasn't taken any photographs yet so I don't know exactly what was done to it.  It is difficult to judge from your one photo how high your motor is off of the floor.  Is it located approximately where the countershaft once was?  Maybe that's what was done to his.
> 
> Over what motor RPM range (slowest to fastest) do you run the motor?  And whatever the slowest speed is, have you noticed any tendency to overheat after running for an hour or more at that speed?



If I am the member your referring to I have a pic n this thread page 2. 

I like the setup you have there. Looks like it could get rid of a lot of wear spots like I have.
http://www.hobby-machinist.com/threads/new-clausing-6913-gear-box-engagement-lever-fixed.


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## Dhector

That link didn't work. Attempt number 2.

http://www.hobby-machinist.com/threads/new-clausing-6913-gear-box-engagement-lever


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## wa5cab

That one didn't work either, but I did manage to locate the photos that you made of the left end of the machine.  Take a look at the photos that Pete posted above of his modification.  You might want to do that eventually.  It's a very neat mod, and about what Clausing might have done had VFD's been common when your and his machines were new.  Now back to your thread.


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## Dhector

machPete99 said:


> I did this a while back, but figured I'd post the info for others that might be interested.
> 
> This setup completely replaces the original Reeves drive and countershaft arrangement. The motor is the original Doerr 2HP 3PH unit. I am using the stock cogged belt size/length, but have fitted the motor with a slightly smaller drive pulley (22T). I redrilled the motor support brackets so they could use the slots previously used for the countershaft support. A piece of 1/2" steel plate is used to get the motor in the correct location, in line with the spindle pulley.
> 
> Mechanical parts, from McMaster-Carr:
> 6495K615 - H Series Quick Disconnect Timing Pulley (1-1/2" wide H series Quick Disconnect 22T)
> 6086K34  - Quick Disconnect SD 7/8" ID 3/16" keyway
> 6484K284 - H Series 63" x 1-1/2" Belt (630H150)
> 99020A420 - 3/16" key stock
> 
> VFD is Hitachi WJ200-022SF, from Drive Warehouse. I am using  4 x 50 ohm 100 watt resistors (in series/parallel pairs for 100 ohm total) for braking. Most of the control items are from Automation Direct.  The enclosure is good sized (14 x 12 x 8), from factorymation, so does not need a separate fan. I am using a (2) pole motor switch as a disconnect, relatively simple control wiring. The original motor flexible conduit has been rerouted to enter the enclosure, near the top. Everything is mounted to a an aluminum plate which can be removed for service.
> 
> The speed control is pricey but industrial quality  (Allied:  Honeywell 53C11K + Schneider Electric ZB4BD922). The control panel is located where you stand so you can change speed etc. while machining.
> 
> Pete



Looking at that setup and reading what you wrote makes me think that machine came with one belt only. Mine has two belts and I'm wondering if it would even be possible to change mine over to what you did to that one. I'd look at the downloads and diagrams but I'm on my phone and it would take hours to check. Any thoughts?


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## Mikebr5

machPete99 said:


> Being able to change speed in the middle of a cut is a nice feature. _*You can dial in the color of the chips.*_


I gasped when I read this... Brilliant!


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## wa5cab

DH,

His machine originally looked exactly like yours does now.  What he did was remove the mechanical variable speed pulley from the motor and remove the entire countershaft assembly above the motor.  Then he mounted the motor where the countershaft was, and he said that he also used a slightly smaller toothed pulley on the motor and a slightly longer belt.  He didn't say why, but possibly to get the required belt length to be an available belt length/  and/or get the desired motor RPM range with the desired spindle RPM range.  Go and read the PM I just sent you.


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## machPete99

Robert described it pretty much exactly, but the belt I am using is the exact same as the upper belt used on the original configuration. There is some tradeoff on the motor pulley sizing between lowest speed, highest speed, and the "hole" in the middle. I leaned towards better low end speed and torque, as I never run much up in the 2000 RPM range.

You can think of the "fixed" cogged pulleys as being near the middle of the Reeves speed range, but with the VFD you can safely double the motor speed, since stock is around 1800 (1740 nameplate) and most bearings/armatures are rated to 3600. I also figured on being able to run at 40% of nominal speed for the low end. You can go even lower but lose a lot of torque.

Top speed calculations for direct drive pulley ratios (keeping spindle pulley at stock 40T) running 120 Hz, various drive pulleys:
(back gear supplies 7:1 step down)
1740 * 2 * 24/40 = Spindle 2088   RPM <--Stock countershaft pulley size
1740 * 2 * 22/40 = 1940                             <--What I used for VFD conversion
1740 * 2 * 20/40 = 1740
1740 * 2 * 18/40 = 1566
1740 * 2 * 16/40 = 1392

NOTE: Above calculations are for 5900 family (59214 12x36) lathes, which use 40T spindle pulley. You may need to adjust these for other size lathes that might use different spindle pulley sizing.


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## wa5cab

For clarification, please confirm that for example 24/40 means 24T 40DP.

I remember now that you commented that you used a spacer plate to get the motor in the proper vertical location for proper belt tension.


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## machPete99

"T" is for Tooth, so 24/40 is referencing the motor pulley (24T, or 24 Teeth) to the spindle pulley (40T or 40 Teeth) ratios.
1740 is the motor normal RPM (not sure why its not 1800...).
The *2 is the doubling of the motor speed by running at 120Hz.

The steel plate under the motor is needed to support it as it needs to hang out of the cabinet a bit so that its pulley is directly below the spindle pulley.
The motor bolts to the plate (from above), the plate sits on the brackets, and there are bolts that hold the plate to the brackets (from below).
The bolts need to be trimmed so they don't protrude through the plate, at least in the rear.

Once I figured out how everything was going to line up I drilled new holes in the motor brackets to match the center of the mounting slots originally used for the countershaft brackets, So I have some adjustability in the motor up and down, to set the belt tension.


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## Ulma Doctor

hey pete you mentioned that you get motor whine.
if you significantly increase the carrier frequency the whine will go away.


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## machPete99

Thanks for the tip, Mike. I increased the carrier frequency from the default of 2KHz to 15KHz and it is much quieter now.

I still do get some gear whine, and may try going to a thicker oil in the headstock at some point.
I am currently using Mobil DTE24, but some folks think DTE25 is better:





						1st post: New to me Clausing 6913 lathe. Basic Maint. Questions....
					

Hey team,  I'm a 4 year school trained, 20 year career machinist....FINALLY have a lathe in my garage at home now!  I found the manual for the lathe online... I want to change all the fluids. The manual calls for all these Texaco Blah blah models of oils that I can't find listings for. Don't...



					www.practicalmachinist.com


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## machPete99

Some additional information about the motor mount plate...

Motor mounting plate used is 10"W x 8"D x 1/2" Thick.
It sticks out from the cabinet rail surface 2-1/2"
The front motor mounting screws are located 1" from the front of the plate, but you should check your motor geomtry on this.
Original motor brackets are redrilled so the captive nut plates can be reused and positioned so they end up roughly centered over slots in the mouting rail.
The motor mount and bracket mounting bolts go into threaded holes in the plate.
Some of the bolts need to be cut so they do not protrude and interfere with the brackets.


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