Cootes Grinder Table Setup

[RP14]

All new at knifemaking and time for me to get into it. Been collecting and saving equipment for a while.

Have a Cootes 2x72 grinder and need ideas to build the table. Have a hard time searching for this. I have a 2.5 hp 1725 rpm motor and ordering a 3 step pulley 2,3,4".

Question I have is the grinder table setup. Looking for the proper starting height, if too tall I can cut the legs down. I am thinking of something like a 16x24 plywood tabletop and the motor on bottom shelf with belts thru top table. My concern other than height is balance, will the cootes be top heavy? Or will the motor take up the balance? Like to see pictures and ideas before I start cutting wood, open to ideas.

Thanks a Million

 

[chrisstaniar]

Not to derail your actual request, but you should get a VFD rather than a 3 step pulley. I did the pulley thing initially and the VFD is a much better.

 

[RP14]

Not to derail your actual request, but you should get a VFD rather than a 3 step pulley. I did the pulley thing initially and the VFD is a much better.

Future plans for the VFD. Money is tight and I already have the stuff other than the motor pulley. Putting most of my funds towards the CNC Router, the knife grinding will be used while the CNC Router is "working" and I am in the same room to watch the router.

 

[MTBob]

I agree with Chris' recommendation to get a VFD for your grinder. There is nothing more important than controlling tool speed (belts in this case) when metal working. The step cones will offer some speed control, but they won't usually give you the speed that is needed, they are clunky to deal with and are often the source of excess vibration.
There are a variety of VFD controllers out there, but I think it's safe to say that most/many knife makers use controllers made by KBAC (typically model KBAC 27D). For a VFD setup you'll need both a controller and a 3 phase motor. All in, that will cost approximately $700 +/-.
To establish the table height for the grinder, place your elbows at your hips, hold your forearm out horizontal to the floor, measure the distance from your hands to the floor. Then use that measurement to determine the the vertical center of the grinder platen. That will give your the about the correct height of the grinder & table. But, there are times when it's good to be able to adjust the grinder height to fit various needs, particularly if someone of a different height is using the grinder. Here's my solution to that problem, though it's probably more than you want to do right now. The scissor jack raises and lowers the table height.

Something to keep in mind: eventually you may want to use the upper portion of the belt for slack grinding. Having access to the side of the grinder can be helpful for that purpose.

 

[RP14]

MT Bob, That's a great setup. Eventually I'll do something like that and I plan on building a grinder like what you have, been collecting materials for it. Now will probably see what I have when the snow melts for building a table like that. As for the VFD, the next grinder will have it and I think the smallest 3 ph motor we have is 5 hp, still looking for a 2 hp. I work on compressors and pressure washers, will check the bone yard as well. We do get new motors that needs to be changed over to explosion proof motors, which is why we have lots of 5 hp motors.
Thank you for the info.

 

[Chris Railey]

Future plans for the VFD. Money is tight and I already have the stuff other than the motor pulley.

You can get the Chinese VFD's for under $100. You will save that in burned edges alone during your first six months making knives with a 3 step pulley. Plus your grinds will improve faster if you have fine control of your speed. MANY people here run multiple China VFD's and have no issues with them.

 

[Chris Railey]

I agree with Chris' recommendation to get a VFD for your grinder. There is nothing more important than controlling tool speed (belts in this case) when metal working. The step cones will offer some speed control, but they won't usually give you the speed that is needed, they are clunky to deal with and are often the source of excess vibration.
There are a variety of VFD controllers out there, but I think it's safe to say that most/many knife makers use controllers made by KBAC (typically model KBAC 27D). For a VFD setup you'll need both a controller and a 3 phase motor. All in, that will cost approximately $700 +/-.
To establish the table height for the grinder, place your elbows at your hips, hold your forearm out horizontal to the floor, measure the distance from your hands to the floor. Then use that measurement to determine the the vertical center of the grinder platen. That will give your the about the correct height of the grinder & table. But, there are times when it's good to be able to adjust the grinder height to fit various needs, particularly if someone of a different height is using the grinder. Here's my solution to that problem, though it's probably more than you want to do right now. The scissor jack raises and lowers the table height.
View attachment 82528
Something to keep in mind: eventually you may want to use the upper portion of the belt for slack grinding. Having access to the side of the grinder can be helpful for that purpose.
View attachment 82536

THAT is a slick grinding table Bob. I just spread my feet wider apart if I need to get closer to the grinder...

 

[KenH]

I second Chris's comments on getting the Chinese VFD. "IF" you've got to purchase the motor, a 3 ph motor isn't really anymore expensive than a 1 ph. The pulleys required for the 3 step setup along with the bearings and shaft will cost more than a Chinese VFD, so it's actually less expensive to go with a VFD. Then 4 or 5 yrs down the road, "IF" the Chinese VFD fails you can then replace it with the expensive KBAC drive.

 

[RP14]

Already have the motor, found a new motor that we weren't using as most units are 3600 rpm and the one we had on the shelf 1725 rpm 2 hp for few years will not be sold, got it real cheap. Been sitting in my shop for year and scratching off my things to do list, the grinder and workbench is my next project to complete list till the snow melts then off to my 54 GMC Truck project.
Next grinder build will have the VFD drive.

 

[Chris Railey]

Well, three speeds are better than one speed. My first two knife grinders were single speed machines and I survived. That is the great part of having your own shop...You can do it your way.

 

[soundmind]

Are you going to mount it against a wall or keep it on a cart?

I mounted mine against a wall and also wasn't sure on the height. I attatched a level 2 x against the wall, then built the rest off of that using screws all around if I wanted to re-adjust the height. On another bench I built I just scabbed the feet to get some extra height I wanted.

I also used the method Bob described for determing grinder height and it work out well.

My grinder is over 100 lbs. It was on a cart similar to Bobs, hanging on the side, for awhile at my brother in laws house. But that was heavy material...I don't know I just think a grinder base needs to be solid.

Happy grinding! Sounds like you have a good selection of motors.

 

[soundmind]

Here's my solution to that problem, though it's probably more than you want to do right now. The scissor jack raises and lowers the table height.

Looks really nice Bob., I thought I was the only one who ever thought of that! You really made that work well.

I threw around the idea of having a table I could raise and lower like that. I read awhile back that some makers grind sitting down and wanted that option during the learning phase.

Never got to it, lol, I'm lazy either way I guess.

 

[MTBob]

I understand about doing what ya can with what ya got, been there done that for a long time. Certainly steps cone speed control has it's place and, in fact, I still use step cones on a couple of machines. But, where I can, I've converted most of the equipment to VFD controls for reasons mentioned earlier.
Not to debate the subject, but I'll throw out another reason that steps cone arrangements are limiting on a 2x72 grinder - and that's the need to swing the machine into the horizontal position. No doubt there is a way to do that with step cones, but is sure would be tricky.
FWIW, here's the method I used to rotate my grinder to the horizontal position, the whole table section rotates. After purchasing my grinder, I now see that Reeder offers a frame that swings to the horizontal position and can be bench mounted. I think a number of other grinders offer that feature too.

 

[RP14]

Got the table built and waiting on the pulley. Decided to mount the motor behind the grinder instead of below to give me some storage space as well as a shelf for a bucket of water. So far this setup seems to balance well. Will know more when I decide to start grinding, can always add extended feet if needed or as one person mentioned, screw it to the wall. Once I gather the materials for a metal table, I'd like to make it adjustable like a member did above. At least this one will give me more ideas as I use it. Thank you for all your ideas.