CHIPMASTER belt-drive conversion

This is also posted on the Home machinist forum. But I'm posting here also for the benefit/interest of CHIPMASTER owners.
As posted earlier I asked some questions re: putting a 3 ph motor on and using an inverter only
to drop the speed as many Chipmaster owners have done when their variator goes.
So going back to the beginning my variator is not shot-it doesn't sound like a dryer full of ball bearings.
But it is loud to me, quite probably because my shop is tiny and at present the lathe sits on a wood floor
with 1/4" steel plates between the leveling feet and the floor to spread the load.
So I knew I was going to have to do something because it became increasingly annoying.

So I looked at 3 ph no dice w/o belt reduction-moot/pointless.
I looked at reeves type variable speed. Our Clausing drill press at work has that and when you
wind it up to 2000 rpm it just screams. Same problem-not a solution.
So I came up with my own solution-sort of.
So lets start with some before pics.
Pic 1 is of the original variator on the lathe on its own cast iron mounting stand/bracket with
the motor mounted underneath.
Pic 2 is the Variator speed control handwheel.
Pic 3 is with everything removed. A blank cavity so to speak.

So my idea borrowed from a lathe we have at work It's badged LANCE,
which I beleive is just a rebadging for USA sold machines.
The name they're known by is Zubal, spanish made.
The lathe has 3 pulleys on the motor and 3 pulleys on the main
spindle. And because the 3 pulleys at the motor slide on a spline
you get 7 speeds plus 7 more with the back gear.
So I took this idea and how loud it sounded when running
and said I can work with that.
So on my version I took the spline shaft from the motor and
moved it over to the intermediate shaft and that allowed me
to use a smaller pulled at the motor for a lower bottom speed.
Next I needed a way to quickly/easily release belt tension and retension.
So I came up with a sliding motor mount.
With the motor mounted on a 1/4" plate that slides in some steel channels.
The motor hung underneath a steel fabricated shelf and tension controlled
by a 5/8" leadscrew and a nut mounted to a standoff and to the sliding mount.
Pic 1 is the motor a 2 Hp Doerr farm duty, mounted to the motor mount
with the channels sitting on the sides and the leadscrew/nut asssembly.
Pic 2 are the pulleys. The motor pulley has the 2 smaller Vees made of steel with
the large pulley bolted on.
The intermediate shaft which mounts to the shelf with 2 pillow blocks
has a pc. of 1-5/8" x 6T spline shaft mounted on the end.
My new taped attachment came in very handy for this part.
Taper on the end of the 1-1/4" shaft and matching taper inside the spline shaft.
The 3-Vee pulley that slides on the spline shaft is mounted/bolted to a spline
coupling that has a flange welded to it which allows the 3 individual aluminum
pulleys to be bolted together.

Pic 1 is of the completed set up and everything mounted and in place
with the 2 vee pulley mounted on the end of he intermediate shaft
driving up to the clutch shaft.
And pic 2 is view of the pulleys through a front access port that I
made by enlarging the original small hole for the original on/off switch.
This was to help speed/simplify belt changes. There is also a lexan cover for the
port to keep out chips.
So you're probably asking how well does all of this work.
All things considered pretty well.
When I got the spline shaft a coupling in I was very dissapointed to see
that the 2 components had the worst fit tolerance of all those I read about
while researching this. There's press fit/sliding while not rotating fit and
sliding while rotating. And let me tell you it was a really loose fit.
My solution was to mount set screws into the splines of the coupling
12 set screws on 6 splines 1 fore and one aft. and then bore the coupling so the set
screws ride in the bottom of the female splines on the shaft and are machined with a radius
for the most contact possible.
In the slowest high range speeds its reasonably quiet but in the higher speeds it gets a bit
clackety which is amplifyed by the hollow metal stand and the wood floor.
The lathe at work has the 3 motor pulleys made of cast iron and the splines slotted into the pulleys.
For a lot less play than the spline shaft/coupling that I bought.
MY final solution will be after I finish rebuilding my Rockwell mill.
I'll machine up a pc of 1045 and mount in the dividing head and use the horizontal spindle
to gang mill 6 splines on the shaft with a very good fit and then turn down the OD after to get a snug sliding fit.
That should almost elliminate any clacketyness and noise. It should be even better than the one at work.
Because the pulleys have a quite large size range/variation several belt sizes are required to cover
all the speed combos and when using a speed in which 2 of the largest pulleys in the set come in close contact
a slightly longer belt is needed. And this lets the sliding pulley go lateral mostly when using the spindle in reverse.
Again this should be remedied with the new spline shaft.
Right now I have a handwheel for the belt tensioning sitting down in Oroville so I'm using a small vise-grip
on the outboard end of the shaft on top of a pc of split aluminum tube and slides off the shaft every so often.
The new handwheel will solve that issue and make speed changes even faster.
The best part. The speed range of this set up is 40 to 2000 rpm. 400 to 2000 in high range and divide by 10
for back gear. Not quite the 35-3000 of the chipmaster with variator.
But the lathe at work only gets 56 to 1600 rpm's and its a bigger lathe and not as rigid.

Recall rklopp converted his Chipmaster to vfd, I think without variator. Sounded like it worked well.

L7

lucky7 said:

Recall rklopp converted his Chipmaster to vfd, I think without variator. Sounded like it worked well.

L7

Click to expand...

I use a VFD to drive my Chippie, but the variator is still in place and works. The VFD is mostly there as a phase converter, and I only vary the VFD speed when I need real slow creep speed, like when winding a spring or threading to a hard shoulder. The VFD is an old LG Industrial 5-hp unit built like a tank. The main noise source on my Chippie is the timing belt between the motor and variator. That makes quite a whine.

Running my Chippie yest and wondering how a guy can tell timing belt noise way back in the motor compartment from variator? Maybe it’s just my crappy ears that have too much jet engine noise time on them, but I can’t tell the difference.

Might be interesting to know what an early Chippie with its direct connected motor to variator sounded like. I’ve never seen one much less heard one run.

L7

lucky7 said:

Running my Chippie yest and wondering how a guy can tell timing belt noise way back in the motor compartment from variator?
L7

Click to expand...

I can tell it's mainly the belt, because the sound became a lot louder when I replaced the belt. The new belt is stiffer and has not yet worn to mate with the 60-year-old pulley teeth. It is getting quieter with use.

I also fell into the trap laid by Tony of lathes.co.uk (he hates the variator). Buying two 3 HP VFD's for my Chippie and my Deckel FP2.

The variator made a knocking sound, so I planned on making a layshaft so I could keep the great RPM range with the VFD.

But I was very lucky to be given an older 3-ball variator that had been killed by it's ignorant owner.

I could use a spare cone part from that, so my variator is still up and running. And I am very happy, that I did not convert it.

As everyone have 3 phase power in Denmark, I have no need of the VFD for conversion and the variator input is specified as 1400-ish.

The VFD could give me soft start, but it starts well enough. And better braking would wear the belts.

The main problem I had was, a 3 phase VFD needs an expensive false current protector (forgot the name) type "B",

so I am saving that expense. And the FP2 doesn't need it - but soft start would've been nice. To get rid of the "clack" start sound.

So to get back on topic - if your variator runs fine, then the correct oil and pretension is all it needs to last a lifetime.

If you have no idea what I mean by that, please PM. The variator works wonderfully and lasts forever, but it needs these two things.

Cheers
Erik

I also fell into the trap laid by Tony of lathes.co.uk (he hates the variator).

Buying two 3 HP VFD's for my Chippie and my Deckel FP2.

The variator made a knocking sound, so I planned on making a two-step layshaft

so I could keep the great RPM range with the VFD. But I was very lucky to be given

an older 3-ball variator that had been murdered by it's ignorant owner.

I could use a spare cone part from that, so my variator is still up and running.

And I am very happy, that I did not convert it. As everyone have 3 phase power in Denmark,

I have no need of the VFD for conversion and the variator input is specified as 1400-ish.

The VFD could give me soft start, but it starts well enough. And better braking would wear the belts.

The main problem I had was, a 3 phase VFD needs an expensive false current protector (forgot the name) type "B",

so I am saving that expense. And the FP2 doesn't need it - but soft start would've been nice. To get rid of the "clack" start sound.

So to get back on topic - if your variator runs fine, then the correct oil and pretension is all it needs to last a lifetime.

Cheers
Erik

chipmaster belt drive conversion

Hi Eric, thank you for your post.
re: the 2 things I need to know.
I have the correct oil, but the pretension you
mention, I'm not quite sure of.
Is that the setscrew adjustment for the drive cones?
Anyway the belt drive conversion is complete and am not planning on reversing it.
I tentatively have a buyer for the Variator, so anything I learn I can pass it on.
If the pretension comes out of adjustment, can that cause extra/unwarranted noise?
JUst out of curiosity, how loud should a Variator in good condition sound?

This is the final installment for this project.
I finally got tired if waiting to get my mill done to make the new spline shaft,
with a tight tolerance fit. I went to a friends with my dividing head and
milled out the spline shaft. Right off the mill it was a bit tight.
One extra pass with the endmill on the bottom corners of each side
of the splines helped. Cleaning up the parted end of spline coupling
and de-burring all the corners as well as filing a chamfer on all the top corners
of the splines, yeilded a perfect fitting spline/coupling.
But... practical application was a bit more complicated.
At the begining of the saga, I used set screws in the spline coupling to remove
as much of the play/slop of the coupling.
So next I had to mill out the set screws.
And where the flange was welded to the outside of the coupling-so that the
3 individual aluminum sheaves could be bolted together to form a step-pulley.
The internal splines of the coupling were tight fitting, not allowing the
pulleys to slide.
A bit of cleanup on the inside of the coupling in this area as well as some filing/fitting
of the spline shaft got me the sliding fit I needed. The pic shows and end view of the fit.
I think the end result was worth it. The motor and pulleys are so quiet that the greatest noise
offender now is the timing belt from the clutch to main spindle.
At the top 2 speeds 1500 and 2000 rpm with the end cover off the belt is quite loud.
But significantly less so with cover on. The system is quiet enough to know there is
very little noise coming from the headstock/back gears. And that the gear-train only
raises its voice at the highest speed in low range-200 rpm.
Job done, now onto the next project.

Nice work, love it when a re-design takes place as you literally take a leap of faith (doing it on my Schaublin 135 Variator), seems there is a theme here ...'Variator' - so is there a Rolls Royce of Variators that actually work for a long time, 50+ years reliably, don't pump oil everywhere, don't clunk rattle or shake and are quiet? Love to know who makes one and what the design is .....

I have lots of different variations-on-the-variator theme in my garage shop.

1. The main variator on the Aciera F5 is a commercial Heinkel (like WWII airplanes) unit, using traditional moveable sheave flanges, one of which is spring-loaded, and a wide V-belt. It did not last 50 years - some rubber bushings down inside turned into elephant snot. I replaced the snot with Delrin, but that made the unit rattle a bit. The F5 power feed variator is the same as on my Aciera F4.

2. Both variators on the Aciera F4 also use moveable sheave flanges, but the belt is a standard "B" section. The sheaves are cut out in a flower-petal pattern so that they can interleave and approach close enough to squeeze the narrow belt. See attached images. These cutouts bend the belt laterally, making it wear faster than normal, and cause a buzz noise. These variators are mechanically bulletproof, and a 50-year life seems not a problem.

3. The Colchester Chipmaster has a Kopp tilting ball-cone variator. Mine is 59 years old and still going strong. I suppose the main issues are complexity, cost, and sensitivity to misuse. They require a special traction drive oil, which fortunately is sold in liters (OK, litres) from the UK.

4. VFD. I have not seen a 50-year-old VFD yet, though I bet there are good ones out there that will make it to that age. I have a 20-year-old 5-hp LG Industrial unit that is built like a tank, but it has needed a new fan and the display cover has gone cloudy. That unit is about 4 times the size of today's 5-hp units. There is a reason most mechanical variators have gone the way of the dinosaurs - after all, speed control in modern CNC machine tools of all kinds is electronic via VFD or close relatives.

5. Monarch 10EE Modular DC drive. Mine is 45 years old but has had plenty of repairs. The latest was to toss the main vacuum tubes and replace them with Scissio Controls solid state units. Sometimes I have scary over-speed on acceleration, I think due to losing the motor's field. The electrical relays have been a headache, and acceleration overspeed seems to be one symptom. The speed variation control is amazing when working right.

See attached Aciera F4 variator pictures.

rklopp nice summary and very interesting read, if I'm not mistaken the one 'issue' with VFD's and I had this commented on when I converted my Hardinge HLV to single phase and ditched the Variator was at low rpm you loose torque which I get as the motor is actually spinning slower to achieve the rpm and has less inertia, with a variator the motor is revving and holding its peak torque.

After the mods to the HLV it certainly did loose grunt at low rpm's which was noticeable when performing some tasks like tapping etc.

I opted to do a big re-engineer on my Schaublin 135 Variator which sadly suffered from a design issue like many where the oil seals fail on the sliding pulley section covering belts in copious quantities of oil, operators then tighten the belts thinking they need it and then you get excessive wear on parts that should not wear! I have copied Schaublins later version which runs in sealed bearings and has no oil feed and hope it will all work nicely after the project has completed - its on this forum if you fancy a look ...

Yes, the motor runs at 1400-ish RPM all the time - it says so in the Allspeeds manual (only speed allowed).
So the torque gets larger the slower the output runs. With a good VFD the torque stays the same at all RPM.
So the variator gives a much larger range of speeds (35-300 and 350-3000 - you can't do that with a VFD).
HP= Torque x RPM...
Oil is Shell Morlina S2 BL10 - nothing else will do...
Cheers
Erik

Oh, I do have a propeller-driven aircraft.
In fact I just went solo (alone) four days ago.
It's an MTO Sport Gyrocopter, and it makes a great sound....
Cheers
Erik

Wally, I suppose the variator has found its new owner.
The pretension is needed to keep the innards together.
The variator has two cones, one for the input shaft and one for the output shaft.
That would of course push the (6) balls away, so they rest against a ring.
The balls touch 3 points: Two cones and the ring. They have to touch all 3 points
through an oil film and they must be pressed together with the correct force.
Like you mention, it's done with the threaded round thingy. Loosen setscrews etc.
It's all mentioned in a manual from Allspeeds.
When running, the variator makes just a splashing sound - nice and not loud.
But the timing belts - oh, oh. They are loud, like Rklopp write.
Cheers
Erik