Thread: Increasing Tormek speed rotation

Welcome to the forum mate!

I'm sure their are a lot of ways you could go about increasing the speed.. I can't comment on the setup/costs and if it would be worth it. I have always found variable speed to be a huge plus with grinders etc.
Changing the size of the drive wheels is probably going to be the easiest however it depends if the motor will have enough grunt. It probably has a small motor stepped right down and has enough torque left over at the lower rpm.

You mentioned MDF and honing. Their are a lot of diy machines on the net/youtube that knock up machines (mostly from plywood) and old motors that would work just fine for what you described. Some of them even have wood pulleys. Speed control on these are easy if you make your own pulleys or if you want to get a bit fancy, Used Treadmills have a pretty strong motor and speed controls built in. New on the net they have a lot of DC motors with speed controllers usually with a reverse (PWMs?). Then their is small 3phase induction motors with a Variable Frequency Drivers to suit single phase power.

On the topic of honing tools, all speeds work but obviously they take different amounts of time. I have seen power stropping done on full speed normal bench grinders with stout fabric wheels and on the other end of the time line with a paddle strop.
Having said that...I prefer to strop as fast as I can now..

I have a Tormek grinder
To increase the speed of the grinding wheel you would need to increase the diameter of the drive wheel.
Personally wouldn't recommend it as the motor is not very powerful and the grinding wheel would probably stall.You are also quite likely to burn out the motor too if you are not careful.

Originally Posted by Uncle Peter

I find it quite slow

It's meant to be slow. You'd also end up with water spraying everywhere if you sped it up. Also not sure if Tormek balance their wheels for higher rpm, so that's another consideration.
Creusen do a slow dry grinder, 1425 rpm.

Originally Posted by mark david

I have a Tormek grinder
To increase the speed of the grinding wheel you would need to increase the diameter of the drive wheel.
Personally wouldn't recommend it as the motor is not very powerful and the grinding wheel would probably stall.You are also quite likely to burn out the motor too if you are not careful.

You mean increase the diameter of the motor or the drive wheel spindle? There are two splindles in the tormek, one is the motor spindle (which runs at about 2800 rpm), the other is the drive wheel (the rubber wheel, which runs at about 100 rpm). Let's not confuse the rpm with peripheral speed. The rpm doesn't change, whether you are close to the centre or close to the edge of the wheel, the rpm stays always the same. So basically if you make the rubber wheel smaller, and make the motor spindle thicker (with masking tape), I suppose that the rpm on the rubber wheel would increase. But if you make the rubber wheel bigger, its rpm would decrease.
I am planning on making a new smaller drive wheel, made of wood, and stick some electrical tape on the edge to make it rubberised, and finish it with a very thin line of epoxy glue as a friction ring. Then I would make the motor spindle bigger with some masking tape.
My goal is to use a wooden wheel charged with rouge, instead of the stone wheel. Why? Because it's fast, cheap, and a stone wheel can't achieve that polish mirror. Now, I have to decide how big will the drive wheel be...

Originally Posted by Uncle Peter

, , , , , I am planning on making a new smaller drive wheel, made of wood, and stick some electrical tape on the edge to make it rubberised, and finish it with a very thin line of epoxy glue as a friction ring. Then I would make the motor spindle bigger with some masking tape.

I don't think there will be enough friction between those materials to get good torque transfer and there is a chance of starting a fire if a wooden frictional pulley is used.

But as BD says the motors on those types of grinders are just too small for higher speed operations

For example the T7 produces 14.7 Nm at 90 RPM which works out to be 141 W of actual working power.

At 800 RPM the torque produced will be at best 1.65Nm
In practice it will be much less because frictional losses by direct contact pulleys is much higher than other methods

By way of comparison a direct drive 750W grinder at 1440 RPM can produces about 5 Nm of torque.
At 800 RPM a 750W grinder is producing 8.9NM of torque

Originally Posted by BobL

I don't think there will be enough friction between those materials to get good torque transfer and there is a chance of starting a fire if a wooden frictional pulley is used.

But as BD says the motors on those types of grinders are just too small for higher speed operations

For example the T7 produces 14.7 Nm at 90 RPM which works out to be 141 W of actual working power.

At 800 RPM the torque produced will be at best 1.65Nm
In practice it will be much less because frictional losses by direct contact pulleys is much higher than other methods

By way of comparison a direct drive 750W grinder at 1440 RPM can produces about 5 Nm of torque.
At 800 RPM a 750W grinder is producing 8.9NM of torque

Thanks Bob, I think there is no risk of fire as long as the wood is coated with tape, maybe duct tape on the motor spindle? Do you know how much loss there is in a direct contact pulley compared to a belt driven one, like in a band saw?
I was calculating speed in a bandsaw from this website: http://www.carbideprocessors.com/pag...alculator.html, the smaller the driven pulley, the higher the rpm, so I guessed right. By the way, even if I get to a 400 rpm, I would consider myself a happy man

[QUOTE=Uncle Peter;1861243]Thanks Bob, I think there is no risk of fire as long as the wood is coated with tape, maybe duct tape on the motor spindle?[QUOTE]
Somehow I doubt that this will have enough friction. It should turn the drive wheel without a load on it but once a load is applied I expect 2800 RPM will slip and melt right through the duct tape.

Do you know how much loss there is in a direct contact pulley compared to a belt driven one, like in a band saw?

By way of comparison the T7 motor is rated at 200 W but based on the torque and RPM figures produces 141W or working power so that suggests an ~30% loss of power with the existing system.
V type Belts and pulleys lose between 4-8%, cogged or toothed belts lose between 2-6%, direct drive like a bench grinder loses nothing.

I was calculating speed in a bandsaw from this website: http://www.carbideprocessors.com/pag...alculator.html, the smaller the driven pulley, the higher the rpm, so I guessed right. By the way, even if I get to a 400 rpm, I would consider myself a happy man

If the pulleys work, 400 RPM will still provide enough torque to do some work although it will be quite slow at doing it.

Originally Posted by BobL

but once a load is applied I expect 2800 RPM will slip and melt right through the duct tape. that suggests an ~30% loss of power with the existing system.
V type Belts and pulleys lose between 4-8%, cogged or toothed belts lose between 2-6%, direct drive like a bench grinder loses nothing.
If the pulleys work, 400 RPM will still provide enough torque to do some work although it will be quite slow at doing it.

Or maybe the tape doesn't slip, and after a few hours it will become as hard as a rock, I don't know, I will seee that. ~30% loss is a lot, so another thing that comes to mind is to try the belt system, buy a belt and bearings, fix the motor so it doesn't move and stay away from contacting anything else, what do you think?

Originally Posted by Uncle Peter

Or maybe the tape doesn't slip, and after a few hours it will become as hard as a rock, I don't know, I will seee that. ~30% loss is a lot, so another thing that comes to mind is to try the belt system, buy a belt and bearings, fix the motor so it doesn't move and stay away from contacting anything else, what do you think?

A belt. pulleys and bearings is not going to make up for the fact that the motor is only 200W.

If you are going to put any energy into this sort of thing I suggest starting with at least a 3/4HP or preferably 1HP motor

I prefer the old battleship approach like this
https://www.woodworkforums.com/f65/atkins-grinder-193863
and this
https://www.woodworkforums.com/showth...highlight=BobL

Mate I reckon the tape idea could have merit. I really doubt their is a risk of fire but you never know. It is good to toss around your ideas on a forum as often you will get a different perspective, and sometimes that's pretty helpful.

I think you will find the little motor is too under powered. Even with a lighter wheel.

If your talking about pulleys and v belts, your a stones throw away from knocking up a whole new machine and I don't think that's a bad thing at all.


http://woodgears.ca/sander/disk_sander.html

Google 'diy disk sander' and you will see, it's within the means of just about any home workshop. A second hand motor and half a sheet of plywood will get you over the line.

I guy on youtube called 'izzy swan' has a lot on diy wood machinery. He has a lot of good information to share but he does a lot of work with wood gears and pulleys. Lots of info on imbedded bearings which you will need for a pulley setup but it's pretty straight fwd.

I have experimented a lot with different types of power stropping wheels but the best I found was laminated cork tiles with a MDF hub. They are light, hold the compound nicely, easy to balance and tend to stay pretty stable through the seasons.

Sorry, I should add that the cork wheels are run on a diy slow speed setup. I run them pretty fast and they are 300 by about 25mm thick so the surface speed is high..but I would not run them at bench grinder speeds.
It was a huge time saving advancement in my workshop. Very sharp tools in only a few mins. Now it's just a few passes over the bench stone then 30seconds on the power strop.

thanks guys. Today I tried some experiments. First I tried to place the rubber wheel on the motor shaft, all was tight and flush, but it was a disaster, there was no friction at all, I don't know why. Then I put back the rubber whell to its usual place, and tried to increase the motor shaft with some electric tape. It was just one tape roll, so there was no big difference in diameter, but the result was good, because the rpm went from 100 to 130, not bad! So happy with the result I decided to make a wooden drive wheel, diameter about 5 inch, I made the gaps for the pin, and put some superglue to harden. On the edge of the wooden wheel I put two electric tapes, and it looks fine. Being the wheel smaller, now I had to make the motor shaft much bigger than before, so I put 4 more tape rolls on it. I turned the machine on, and the tape started to shift on one side, disaster...So now I think that I can't use more than one tape on the motor, and I think all I can do now, is to buy a bearing and see how it goes, because the wooden wheel seems ok.

Tired of experiments, hehe, I learnt anyway that Tormek has to be slow, and trying to use rouge compound is useless at that speed. I was always intrigued by how fast it is to sharpen tools with a low speed grinder, like in these two clips
https://www.youtube.com/watch?v=lliGsi6XbbE
https://www.youtube.com/watch?v=C2yJnN_aFBg
But I can achieve the same mirror polish with my Tormek clone, not with the stone wheel, and not with the rouge, but with the sandpaper. I glue sandpaper, grit 1000, all over the wooden wheel, I can sharpen tools in just two minutes, and flatten comfortably also the blade's back. Using the rouge is impossible at low speed, but for the moment I will stick to this technique: Tormek clone+wooden wheel+sandpaper grit 1000.

Nice one uncle Peter! At the end of the day, if you have a system that works for you then your on the money!

I'm surprised you did not get any results with stropping at the lower speeds. Paddle stropping works and is viable even at the slow hand speed work.

What compound are you using and on what surface?