converting a Kalamazoo 1SM

[grepper]

I suspect the speed vs heating thing is known and very well understood.  There is probably some formula to answer that question.  No doubt in my mind slower is better when it comes to heat generation.

I don't want to take this great thread off topic.  Sure is easy to do!

[Ken S]

More accurate RPM/SFM data:

I spent some time this afternoon getting accurate RPM readings with my tachometer. The trick to getting accurate readings is to angle the tachometer so that the light does not reflect back into the sensor.

The unaltered control box gave a speed range of 1338 to 2900 RPM. Using the formula circumference x RPM = SFM, a four inch drive pulley = .334 feet. Therefore, .334 x 3.14 = 1.05   
1.05 x 1338 = 1405 SFM That is not much slower than the Kally with the 1725 RPM motor, although is is just over half the speed of the Viel with the 1725 RPM motor and the six inch drive pulley.

Using the control box where I adjusted the pots, the low speed was 740 RPM, which would be
1.05 x 740 = 777 SFM. 

I adjusted the control pots conservatively. The speed could have been lower. 

Adjusting the speed can be done independently of the conversion. The motor and control box are connected by a plug. I have been using my modified control box with both motors. I just switch plugs back and forth. My original control box has a reversing switch added to it. I plan to eventually adjust the low speed and add a reversing switch to the second motor control. As a practical consideration, plan to purchase a digital tach (not expensive) if you plan to adjust the motor speed.

Stay tuned........

Ken

[Mark Reich]

I don't think I've noticed a belt loading with aluminum.

In my experience, aluminum is easy to work. Seems like it sheds heat quickly, so I don't recall problems.

I do know that faster belt speed gets quicker results.

Mr Ken, have you tested that motor to determine whether you actually get more torque at low speed? I don't recall that type of setup working that way.

[grepper]

You are right, Mr. Mark. Aluminum conducts heat way better than stainless steel. You know, they make heat-sinks out of the stuff. As far as common metals go, stainless steel is a rather poor conductor of heat. I suspect what this means is that when grinding heat is not readily lost to the cooler body of the blade.

https://www.engineeringtoolbox.com/therm...d_429.html

[Ken S]

Good question, Mark. My reference to torque is strictly seat of the pants. With no supporting evidence, using the smaller diameter drive pulley allows more DC current flowing through the motor for the same RPM and SFM. I am really more interested in the slower speed than in power.

I have reached a  conclusion working with both the Viel and the Kally: I don't see much sense in converting the Viel to variable speed without also converting to the 3 3/4” drive pulley. The speed advantage is just better with the smaller drive pulley. For those who occasionally want the full speed of the fixed motor with the six inch pulley, the high end of the variable speed motor is faster than the fixed motor. It can equal the SFM of the fixed motor.

Comparing the stock and modified versions of both, I think the modification process offers more for the Viel than the Kally. The Kally comes from the factory with a smaller drive pulley and lower SFM. It also comes with a fixed, but very strong motor. Switching the drive pulley on the Viel gives the smaller pulley advantage, however, it requires the variable size motor to fit the Viel frame. 

I am looking forward to working with both machines.

Ken

[Rupert Lucius]

More accurate RPM/SFM data:

I spent some time this afternoon getting accurate RPM readings with my tachometer. The trick to getting accurate readings is to angle the tachometer so that the light does not reflect back into the sensor.

The unaltered control box gave a speed range of 1338 to 2900 RPM. Using the formula circumference x RPM = SFM, a four inch drive pulley = .334 feet. Therefore, .334 x 3.14 = 1.05   
1.05 x 1338 = 1405 SFM That is not much slower than the Kally with the 1725 RPM motor, although is is just over half the speed of the Viel with the 1725 RPM motor and the six inch drive pulley.

Using the control box where I adjusted the pots, the low speed was 740 RPM, which would be
1.05 x 740 = 777 SFM. 

I adjusted the control pots conservatively. The speed could have been lower. 

Adjusting the speed can be done independently of the conversion. The motor and control box are connected by a plug. I have been using my modified control box with both motors. I just switch plugs back and forth. My original control box has a reversing switch added to it. I plan to eventually adjust the low speed and add a reversing switch to the second motor control. As a practical consideration, plan to purchase a digital tach (not expensive) if you plan to adjust the motor speed.

Stay tuned........

Ken

OUR FINDINGS -

more than a dozen and half Penn control boxes have passed thru our hands - NO TWO were close to the same RPM in controlling the motors  RPM's

YOU question the RPM range?? if you think it is too high - most likely it is.

[Ken S]

A minor problem with the variable speed motor corrected:

The Penn State Industries variable speed motor is primarily designed for mini lathes. (PSI caters primarily to pen turners.) As such, the motor shaft has a three step pulley mounted. I have one more conversion to complete (a second Viel, using all the newly designed and modified parts).

With a good gear puller, the pulley is easily removed. With my cheap puller, it is at best a nightmare. My puller has a thin and short sliding T handle which provides almost no leverage. I have had this puller for more than twenty years. I have no memory of purchasing it. Tools, both good and mediocre, last a long time. I almost always buy quality, heavier duty than I need tools. This tool is one of the almost in almost always.

I ground off enough of the flattened end of the T handle to remove it. Then I ground two flats using the Kally equipped with Mark Reich's excellent platen. The flats allow a 3/8” open end wrench to fit snugly. Substituting a heavy duty twelve inch Crescent wrench will give plenty of leverage. The threads on the puller are poorly cut, very shallow. I think I can remove the pulley working carefully. Twenty years ago, I would have purchased a pro grade puller. This may well be the last time I use the puller; it should suffice.

Modifying the gear puller is an example of the quick work the Viel or Kally make of many shop tasks. A belt grinder is a very handy shop tool.

Ken