Why Disk Sander ??

I have never even considered using a foot switch with my VFD disk grinder. Not saying it not good, just never thought of it. With disk turned slow, I never felt the need. Maybe I'll try it sometime just to see.

 

You put blade to lay flat on disk and press foot switch ...No chance to grind where you don t want in first contact with blade to disk .

 

How often are you shutting it off and on to do that process? With length of blade and difference of rotational speed, I still pass the blade across the disc just like one would pass the blade across the belt. To do a hold down, start, stop, lift you’d need to only be doing 3.5”-4” long blades max. I wouldn’t think you’d be able to hold it on in one place for very long before heat build up either. Coming in with light pressure until you feel the blade well engaged with the disc before increasing pressure works just as well on the disc as it does on a belt grinder I would say.

I could see the foot switch maybe being useful for softer materials like flattening scales where even light pressure can knock a corner off. With variable speed turned down though I don’t really find even that to be an issue.

 

I remember one day I was absolutely determined to flatten all the bone pieces I had and get them down to 1/8" stock and prepped for jigging. I must have had 2 dozen sets of scales worth of bone. I put on my respirator and fired up the disk sander, more determined than ever to finish that job. 4 hours later, I looked around, and my arms were completely covered in bone dust, with the hair follicles all frosty looking, and the entire shop had a nice light white dust coating. It was almost like it snowed in the shop. And I was only halfway done. I took the respirator off, smelled the worst smell I have ever smelled, and then took the disk sander outside and put it on a pedestal, and set up a fan to blow the dust away from me.

 

That is a good point. Even with disk turning slow you've got to be careful when placing bevel to disk so it's just right for a nice clean grind line. I WILL be trying this. I've got a foot switch I use on portaband so it will be easy to move over and try.

 

For me, I'm thinking the foot switch will help out the most when flattening and squaring up a ricasso, mainly on hidden tangs in order to get everything centered from tip to butt and a seamless guard fit. It can be such a small surface that trying to press it flat against the spinning disc, even while at its slowest, can be a bit sketchy and make hard to apply even pressure where you want it right from the start.

I still have my disc vertical so that makes it even more difficult since you have only the thickness of the stock to pinch onto in order to hold and press it flat while making sure not to grind off the tips of your fingers when squaring up the ricasso. My next step is to mount it on a hinged board to flip it from vertical to horizontal and add the foot switch. Having it horizontal will also make it nice for establishing my edges as well as better for flattening handle blocks or scales... and probably pretty much everything other than bevel grinding/flattening that doesn't involving using the work rest.


~Paul
My Youtube Channel
... (Some older vids of some of the older knives I made)

 

It is far more accurate for flatness and consistency to have the material laid flat on the disc while stopped, then hit the foot peddle for on then hit it off when done.
No chance of losing flatness while lifting the part from the disc

 

. my whole cellar would get a layer of dust on everything, even with a dust collector. enclosing the grinders in a room made of sheet plastic curtains took care of it. leave 2 or 3 inches space between the floor and the curtain so the dust collector will not pull the curtains in toward you from the vacuum in the room.

 

Well, I do have a foot switch but it's a 120 vac switch. The VFD disk grinder will require a 220vac switch so it will be a while before I'm able to try a footswitch with my VFD grinder. The idea does sound good.

 

I honestly think too many people use small, underpowered disc sanders. A good sized powerful one is a GAME CHANGER for wood and metal.

Ill post some photos of the knives ive been making soon,

But I have 3 disc sanders currently, a 1hp 9 inch disc with a VFD, a 12 inch 1hp grizzly (Both of which are for sale)

but I recently got a 16 inch disc sander with a 1.5hp motor, reversible, and a 45 pound disc on it. Anyone who says disc sanders cant hog off material has never run a 50 grit disc on this monster. They are great for bringing everything back into plane between grinding, and for finishing they leave a really even , flat surface that makes a great place to start hand sanding from.

If anyone is in Socal, id be happy to show you how a big disc grinder can up your knife making!

 

Or, you could use a solid state power relay, controlled with your existing footswitch. I don't know how expensive a 220V foot switch is, so it might be a wash, cost wise.

 

Not at all, a vfd is definitely nice to have, but what's more important than speed control is size and power in my opinion.

 

It really depends what you are trying to do with it. I’m sure that beast works great for you when processing down big lots of wood, but most folks use the disc sander more in the finish work category. Power also isn’t really the issue for hogging with a disc. The issue is grit life. There is simply more grit area over a belt than a disc of paper (and I say that as someone who currently does all grinding on a disc). For how most would use a disc, size and power I think are the least important. A 1/2 hp 9” with VFD and reverse is really all that’s needed for how the average knife maker will use it.

 

A 16 inch disc sander has about 200 square inches of grit, compared to a 2 x 72 belt which has 144 square inches.

I have found using a disc sander to be really helpful, not just for woods but for finishing and removing metal. I didnt really like my 9 inch, but i do enjoy the larger one.

 

personally for me a disc for knife maker really need a vfd and be reversible.

 

They sell 3phase disc sanders with vfd at trugrit
I bought a 3phase 220volt motor and I just bought the disc from trugrit and hooked it up to my VFD my grinder runs on

 

trugrit and pheer both sell complete ready to go packages. You can also get just the components to build your own. I use “build” very loosely. Basically you are just screwing a disc onto a motor shaft and voila. Usaknifemaker has the Beaumont parts to assemble your own. I have one of those discs from usaknifemaker. I did not get the table setup because the table is the most expensive part. I have plans to fashion my own table, but I’ve actually just used it a lot without a table.