CBN wheel grinding motor

[Lasse Hilbrandt]

I find that a new Tormek is too expensive, so I bought a copy made by Sheppach. I returned it as soon I unpacked it because i found it to be of too low quality.

Now im thinking of just fitting a CBN wheel to an electric motor, but most of them I find for sale has 1450 revolutions pr. minut. Is that too fast ?
Should I try to fit a frequensy converter or one with a gearbox ?

What is the best speed for CBN wheel ?

[Tom M King]

The tool stays on them such a short time, that I doubt it matters a lot. I couldn't find a slow speed one that would run smooth enough for me, so I got a regular speed one and tried that. I would have sent it back too if it didn't work. I've been using it for a couple of years, and haven't blued an edge corner yet at 3400 rpm, or whatever the exact speed is around that. I ordered two slow speed, cheap ones, tried them, and sent them back. I ended up with one that wasn't so inexpensive, but really smooth.

[Lasse Hilbrandt]

So you are using a motor that runs 3400 rpm ? Then I shouldnt worry about 1450 rpm then. When you say smooth, do you mean with les vibration ?

How much KW is sufficient ?

[Tom M King]

331418This is what I mean by smooth. I've posted this a number of times, so a lot of members are probably tired of seeing it, but it's stored here, so easy to get to. Not only are those things sitting on it while it's running, but after I kept putting stuff on it, I decided to go to the truck and get the camera. The pieces were still there when I came back with the camera, and took this picture. Notice that I hadn't even tightened down the nuts holding it on the plywood base yet. Yeah, I don't think speed makes a whole lot of difference, unless maybe you are heavy handed.

[David Eisenhauer]

To your original question - the 1450 rpm motor you have found would be considered "slow" for grinding purposes and would work just fine. As Tom explained, less vibration is very much preferred and is probably more important than the speed. If I went new, I would consider the Metabo Tom uses.

[Ray Selinger]

His 1400 rpm motor is like our 1725. It's the difference between 50 hertz and 60 hertz , European and North American.

[Lasse Hilbrandt]

331418This is what I mean by smooth. I've posted this a number of times, so a lot of members are probably tired of seeing it, but it's stored here, so easy to get to. Not only are those things sitting on it while it's running, but after I kept putting stuff on it, I decided to go to the truck and get the camera. The pieces were still there when I came back with the camera, and took this picture. Notice that I hadn't even tightened down the nuts holding it on the plywood base yet. Yeah, I don't think speed makes a whole lot of difference, unless maybe you are heavy handed.

Tom. thats a nice set-up. what CBN wheel are you using and do you have one on the other shaft too ? The Metabo DS 200 grinders I can find in europe has a 1 1/4 inch shaft. CBN wheels from Dway has only a 1 inch shaft.

[Tom M King]

I only have the one wheel-a 180. I thought I'd try one, and order a coarser one for the other end later. There was never any need for a coarser one. The wheel is a Dway curved edge. The flat on this one is nice and flat, and has stayed flat. Derek Cohen had trouble with an identical model not being flat. Since I have never had a use for the curves, and with Derek's trouble, I'd get a straight one if I were to do it again. I don't remember the shaft size. They were smaller than 1-1/4 though. It needed a bushing that wasn't a standard size that Dwayne offered. I found a bronze bushing the right size.

I have other grinders, so didn't have a need to put anything on the other end. I certainly didn't want to put a friable wheel on there to compromise the smoothness, or have to fiddle with balancing.

[Tom M King]

If you can find a 1400 rpm motor that would work, I think it would be fine. If I hadn't been planning to get two wheels to start with, and had thought about just a motor, I would have done that.

[Lasse Hilbrandt]

Ok thankyou

[Lasse Hilbrandt]

I found a new problem with just using an electro motor. Most of them has no taper towards the shaft, and their shafts are often very short which will mean the CBN wheel will be positioned very close to the housing......

[Allan Speers]

IMO, the best way is to use a separate arbor, pulleys, and motor.

You get less vibration, all the clearance in the world, and you can adjust speed by changing pulleys. (or even rig a Reeves drive, if you're that type...) The only downside is that they take up significantly more space.

My camera's not working right now so no pics, but I have such a system, and the beauty is that the same motor drives a second arbor on the back of the table, which I use for 2 buffing wheels. It's easy to find cheap arbors & shafts on Ebay, or new ones for not too much $$$, such as the one sold by Stewart McDonald.

[Lasse Hilbrandt]

Allan
I agree a set up like that would have many advantages, but im pretty sure the space it will take up, the time to build, the cost to build, will exceed the advantages. Tomorow I will go look at a second hand grinder that has the technical data im looking for. If it runs as smooth as the seller claims its a bargain at 60$, then ofcourse I still need the CBN wheel and make up my mind if I should go with the Veritas tool rest or the Tormek

[Lasse Hilbrandt]

I just bough a second hand grinder that I think will suit my needs. In a future not so far away I will have to decide if I should go for the tool rests from Tormek, like Derek, or the Veritas tool rest.
Feel free to chip in.

Also, I need to decide if I should buy a 25mm or 40mm wide CBN wheel. I know that the 40mm is wider than the slot in the Veritas tool rest, but I guess that can be modified.

I dont want to spend the extra $ for the 40mm if the 25mm is plenty sufficient.

All thoughts are welcome.

[Tom M King]

I'm using the Veritas stand, as you can see in a corner of the picture. I had already cut out the opening for a water wheel I had before, so it's even a little too large of a cutout now, but works just fine. It's a completely stout simple stand that's easy to adjust. The Tormek of course offers a lot more versatility, but I don't really use it for more than plane irons, and chisels, and a very rare once in a while turning tool, so really don't need the Tormek stuff. The wheel only gets used to correct a damaged edge, which hasn't happened in a good while.

I would want the wider wheel because it cuts so fast that you don't need to go side to side if you don't have to.

[Chuck Nickerson]

[QUOTE=Tom M I've posted this a number of times, so a lot of members are probably tired of seeing [/QUOTE]

I never get tired of seeing it. It's why I sprang for a Baldor 6" slow speed grinder.