Disc Sander recommendation? "VFD? Reversiable?"

Greenberg Woods

Greenberg Woods

Joined
Dec 27, 2013
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Hey Guys, i think im gonna get a disc sander. I was planning on getting the grizzly 12 inch "Seems to be the most popular"

I was wondering if anyone had any other reccomendations. How important is VFD? How important is it that it be reversible?
 
From what I've seen, most people recommend a 9" disc so you can use sheet sandpaper instead of buying the pre-cut sizes. Saves you a lot of money and you can use whatever paper you like and not be restricted. I would also want the reversible to be able to use both sides of the disc depending on what I was working on.
 
Let me be clear, I have zero experience using a disc grinder in the knife making realm. But all of my research points to exactly what Jrmysell states as far as consumables. 12" and you're stuck using 12" expensive abrasives. 9" you can use any paper you can get your hands on. For me, that's a no brainer. Bigger isn't always better. I have a KBAC-29 I use for my new grinder, I'll be using it to run a disk once I build/but one.
 
One significant advantage a 9" disk has over a 12" disk is that you can use standard abrasive sheets trimmed to fit the 9" disk. Depending on the abrasive media, this can save some money over pre-cut disks. If you are just sanding wood, spend money on dust collection rather than options on the sander. If you want to sand metal too, then I would say variable speed is probably more important than reversing, but once you've got the VFD, reversing is a fairly trivial add-on. Reversing may complicate dust collection and work holding though.
 
VFD/reversible is a must, IMO. As for size, I'd definitely go with 9", as there are much more options for abrasives, and it's much cheaper to cut from a 9x11 sheet. In fact, most "9 inch" hubs are actually only 8 7/8" or so, to make it a little be easier to center the paper.
 
Also to echo the last post, I think the 9 inch is better than the 12 inch because you can buy the 50 packs of the rhynowet red paper and use it on the disc.
 
I think a vfd is a must. I use both sheet paper and ceramic discs on my 9". I don't have it set up to reverse yet but eventually I'll get around to it.
 
kuraki said:
I think a vfd is a must. I use both sheet paper and ceramic discs on my 9". I don't have it set up to reverse yet but eventually I'll get around to it.
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avs3323 said:
Also to echo the last post, I think the 9 inch is better than the 12 inch because you can buy the 50 packs of the rhynowet red paper and use it on the disc.
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knife to a gunfight said:
VFD/reversible is a must, IMO. As for size, I'd definitely go with 9", as there are much more options for abrasives, and it's much cheaper to cut from a 9x11 sheet. In fact, most "9 inch" hubs are actually only 8 7/8" or so, to make it a little be easier to center the paper.
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What grits do you like to have on hand? I was thinking 60, 100, 220 ad 400.
 
I keep 60 and 120 in the PSA discs and 100-2000 in sheets. But I rarely use higher than 220 on the disc, I know I use it differently than a lot of guys. For me it's more useful for handles than anything. Doing mitered joints and getting stuff flat quickly. If I did more kitchen knives I think I would use it quite a bit more.
 
Greenberg Woods said:
What grits do you like to have on hand? I was thinking 60, 100, 220 ad 400.
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I have 120, 220, 400, and 600

I am still relatively new to knife making, so I'm still working on getting a good process

I usually do 60/120 on the belt grinder, then go 120-220-400 on the disc grinder, then to scotchbrite belts for kitchen knives

One tip I found useful, if you end up getting a disc grinder, cutting a rubber sheet and using it between the sandpaper and the disc makes things a lot smoother
 
Ben,
I have the 9 inch from trugrit and it works great. I just use 3m feathering adhesive to put my rhynowet sheets on and trim around them. Now, one thing to remember if you are doing large blades get the 1 degree bevel disc that way you can grind the blade on the side of the disc going down and the other side isn't lifting up on the blade.
 
If you want the best then get a Rod Nielsen magnetic disc grinder in the 8" size and get a variable speed reversible motor for it. The magnetic part allows you to change discs without wasting sandpaper. He also has a tapered disc that allows going past center without kick backs as I call them. Truly a fine machine.
Frank
 
I originally had mine set up with a vfd, but I had to move that motor to my drill press on short notice and it currently has a 1.5 HP 1800 RPM 1PH on it. It still does what i need it for (rough flattening scales, squaring bolsters). I used it a little bit on blades, but I need to get a better quality disc. My current disk is not a good tight fit on the shaft and it has too much run out.
 
Ben, I've got two available for you
i'll be home Fri if you want to come look
one has a tapered disc, the other is steel flat
both are wired with male twist loc to plug into your VFD

and IMO and experience, the red 9x11 sheets are a waste of time, unless you need the higher grits.
the PSA discs cost more but are the way to go/
 
Because I use mine to grind blades mostly, reversible is a must for me. Without it you'll have grit and steel flying up in your face when grinding the opposite side of the blade.
I bought a 1 HP 3ph motor and KB electronics VFD. Initially I had the Nielson system but have since switched to a 1 degree disc from TruGrit. Works great for me. It's not a big deal to switch paper quickly using 3M feathering disc adhesive.
 
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