-
The BladeForums.com 2024 Traditional Knife is available! Price is $250 ea (shipped within CONUS).
Order here: https://www.bladeforums.com/help/2024-traditional/
variable speed
- Thread starter dozuki
- Start date
- Joined
- Oct 27, 2005
- Messages
- 2,527
My opinion is that the cost of that would outweigh the benefits. You don't say whether or not you can handle the high speed or not. If you're able to handle the high speed, keep the money in your wallet and keep making knives at the higher speed, until you have enough for a 2 x 72, and use the money towards a variable speed for it.
- Joined
- Oct 20, 2008
- Messages
- 5,547
For a cheap/ possibly pretty much free if scrounged variable speed option, you could rip the DC motor and speed controls out of an old treadmill or even buy the motor and controls off of flea-bay. (Still pretty darn cheap.) If you can fit that DC motor onto your 2x48 grinder chassis it could work out pretty well. Check this link out for instructions on using treadmill motors this way: http://www.instructables.com/id/Use_a_Treadmill_DC_Drive_Motor_and_PWM_Speed_Contr/
A lot of guys have used these on lathes, drill presses, etc. with success.
A lot of guys have used these on lathes, drill presses, etc. with success.
My first grinder was a Sears 2 X 42 combo (8"disc). Yep, it's FAST and I found I did not care for it all that much. Fought with it for awhile then broke down and bought a KMG.
After getting my KMG I tore the Sears down, discarded the factory motor and mounted the 2 X 42 frame to a 1 HP DC motor. I also added and extention arm to the frame so that I could run 2 X 72 belts and fixed a small wheel grinding (KMG) set up to it. The 8" disc grinder was also mounted to a 1 HP DC motor.
If I were to use the belt grinder for general knife grinding (not just small wheel work) it would need to be at least a 1 1/2 HP motor.
If I hadn't already had the DC motors and drives, it would have been pretty darned expensive (3 phase motor and controller would be cheaper). But the basic mod to run 2 X 72 belts is really quite simple and not very expensive.
The variable speed set up is, to me, essential and well worth the cost.
Just my $.02
-Mike-
After getting my KMG I tore the Sears down, discarded the factory motor and mounted the 2 X 42 frame to a 1 HP DC motor. I also added and extention arm to the frame so that I could run 2 X 72 belts and fixed a small wheel grinding (KMG) set up to it. The 8" disc grinder was also mounted to a 1 HP DC motor.
If I were to use the belt grinder for general knife grinding (not just small wheel work) it would need to be at least a 1 1/2 HP motor.
If I hadn't already had the DC motors and drives, it would have been pretty darned expensive (3 phase motor and controller would be cheaper). But the basic mod to run 2 X 72 belts is really quite simple and not very expensive.
The variable speed set up is, to me, essential and well worth the cost.
Just my $.02
-Mike-
- Joined
- Apr 14, 2007
- Messages
- 2,738
Mike, any chance for a picture of your modded 2 x 42?
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Aug 20, 2004
- Messages
- 38,518
There are some cheap and easy mods :
1) If the unit has the motor directly coupled to the disc and belt, remove the sanding disc, exposing the shaft(you will probably have to remove all the shields and stuff on the disc side). Put on a pulley and drive it with a V-belt from a motor mounted under or behind the sander. You can pick the pulley sizes to get the speed you want.Just leave the old motor in place. To run it a high speed, take off the V-belt and use the original motor to power.
2) If the unit has a belt drive ( I don't know which grinder you have, but most Sears sanders have a belt drive.), then all you have to do is cut out or remove the shields at the sanding disc, take off the existing belt, and drive the existing pulley with an external motor as in #1.
3) Depending on the unit and how it is set up, you may be able to just change the drive pulley or the arbor shaft pulley to slow it down. If this is an option, it is the cheapest.... $5-10 and an hours work.
Using a cheap DC motor and drive in #1 and #2 would make the unit variable speed ( not the best setup, but it will work for a hobby unit). If you use a treadmill motor, try to make some sort of shield to keep the dust off it. They are open framed motors. Vacuum/blow the motor out after every use. If you don't ,they will soon be fried.
An old 3/4HP motor will work well with a multi-pulley, too.
Look around for an old two speed washing machine motor. Most are only 1/2HP, but they are good to drive two-speed buffers and light duty sanders.The good thing about them is they are heavy duty motors, and already have a V-belt pulley attached.
Stacy
1) If the unit has the motor directly coupled to the disc and belt, remove the sanding disc, exposing the shaft(you will probably have to remove all the shields and stuff on the disc side). Put on a pulley and drive it with a V-belt from a motor mounted under or behind the sander. You can pick the pulley sizes to get the speed you want.Just leave the old motor in place. To run it a high speed, take off the V-belt and use the original motor to power.
2) If the unit has a belt drive ( I don't know which grinder you have, but most Sears sanders have a belt drive.), then all you have to do is cut out or remove the shields at the sanding disc, take off the existing belt, and drive the existing pulley with an external motor as in #1.
3) Depending on the unit and how it is set up, you may be able to just change the drive pulley or the arbor shaft pulley to slow it down. If this is an option, it is the cheapest.... $5-10 and an hours work.
Using a cheap DC motor and drive in #1 and #2 would make the unit variable speed ( not the best setup, but it will work for a hobby unit). If you use a treadmill motor, try to make some sort of shield to keep the dust off it. They are open framed motors. Vacuum/blow the motor out after every use. If you don't ,they will soon be fried.
An old 3/4HP motor will work well with a multi-pulley, too.
Look around for an old two speed washing machine motor. Most are only 1/2HP, but they are good to drive two-speed buffers and light duty sanders.The good thing about them is they are heavy duty motors, and already have a V-belt pulley attached.
Stacy
I think Ickes nailed it... I have the 2x42, and it's my only grinder right now. Learn to live with the limitations (wicked fast), or save up and get a real grinder. In spite of the blazing speed, you can still turn out some good knives on it if you're willing to practice and booger up a few. By the time you invest time and money in fixing it, you could have made and sold four or five knives and bought a grizzly. Another two weeks and it could be 10 knives and a KMG.