Disc sander questions

Fixall

Fixall

Brian
Knifemaker / Craftsman / Service Provider
Joined
Mar 26, 2018
Messages
5,436
Hello!

I hope you are all doing well tonight!

I am currently in the market for a disc sander. I know there are a few threads on the topic, but I didn't really find a definitive answer to my questions in them.

To start off with, the sander will be more or less used exclusively to square up scales and blocks... And probably quite a few of them. In the future it may be used on steel, but I imagine that is still quite a ways off, as I am still working at becoming proficient in other areas of making a knife.

The first decision I'm trying to make is 9" vs 12". I know that the sandpaper for the 9" will be cheaper since I can just purchase sheets, but I would like to disregard that aspect for now. Results are more important for the time being. I also understand that the 9" would likely be the best bet for future steel work, but would the 12" be significantly better for flattening scales and blocks? I'm not opposed to purchasing a 12" for now, and then purchasing a 9" later down the road when my skills advance.

I imagine if I go with a 12" now for wood, and a 9" later down the road for metal, there would be no reason to go with a 12" VFD/reversible model, correct?

And what about brands? I would definitely prefer to avoid the Harbor Freight Central Machinery model. I would like decent quality, but not crazy overkill. It looks like there are several models all around the same price; Grizzly (I'm biased towards them as there headquarters is just down the road from me), Shop Fox, Rikon, Delta, and Eastwood are all within about $30 of eachother. There is also a WEN for about $50 less than the brands I listed, but I'm a bit unsure about them.

A buddy of mine takes a different approach and uses a spindle sander, but from what I've seen, it seems really inefficient.

What do you think?

Thanks for the help!
 
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I use a 12" for handle work. Looking to upgrade to 16" though. Reverse and variable speed is really useful. Reverse especially when doing work along the spine. Variable speed is great for different materials. I keep a an 80 grit disc on it.
 
Go get the 12" Burr King straight away :p

MrVYsk8.jpg
 
I'm happy with the AMK 9" with VFD.
People making folders have expressed other preferences in the past.
I notice in Kyle Royer's YT videos that he has an AMK also, although to my knowledge he isn't making folders either.
 
I would get a 12” for handle blocking and later the 9” if u like

btw you can also use a Kalamazoo S4. I changed out the motor for a baldor 1725 rpm. I turn mine on the side rotated 90 and have the belt running away from me

i like the Kalamazoo concept alot because of quick change versatility of belts
 
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Good info, thank you.

Good point about heating up the wood too much. The belt sander I am currently using spins at about 1200rpm and even then I have to be pretty careful not to overheat ebony so it doesn't crack. It looks like most of the disc sanders I've been looking up run at about 50% higher rpms. Sounds like a VFD is a must then (and if I'm going with a VFD, might as well get one that is reversible too).

I was hoping to spend $300 - $400 on the disc sander, but it sounds like this might be one of those buy once, cry once situations.

Maybe a higher end 9" is the best option if that's the case? I did like the idea of having a designated 12" with 80 grit for blocks and scales, and a 9" VFD for steel and handle work since it'll be a lot cheaper to swap sandpaper, but maybe I need to just let that idea go?

Haha, definitely no budget for a Burr King at the moment. Maybe some day in the future if I actually decide to try to sell a knife, lol. For now, this is just a relaxing hobby that I'm enjoying. I have about 100lbs of wood to process though and the cheap Craftsman and Harbor Freight crap I have just isn't performing at the levels I would like. I seem to be somewhat infatuated by different wood species and steel compositions. I could look at wood figure and steel spec sheets all day, lol.
 
I also have the AMK (9") and use it mostly for handle work with occasional steel flattening. I think VFD is important. I'll flatten at say 50% coming off the bandsaw then crosshatch it with pencil again and slow it down to say 20% usually get flatter results that way, at least with my hands. Personally I'd just go with the buy once with a nice 9".
 
Id highly recommend 12” or larger for squaring and working handle blocks, one you have more surface area without having to use both halves of the disc, you don’t really want to run the block past center and the paper closer to the center spins slower than the edge so the larger the edge is the easier it is to be able to square a whole side of a block. Another suggestion other than just variable speed is a foot switch, specifically what’s called deadman foot switch. That allows you to place the block on the abrasive with the sander off and start the sander with your foot so both hands are holding the work, when you release the switch the sander turns off, you will get flatter blocks that way because you have a better chance of avoiding sanding a angle into the corners of the blocks.
 
I think a 9 inch is plenty for all your handle/knife needs. Getting quality sandpaper is easier and there are more options for the disc itself. To put it into perspective we’re arguing the ability to square up handles on a 4.5 vs 6 inch face yet we grind our surface ground blades on a 2 inch wide belt.
 
Not to hijack but I have a question that went unanswered in my own disc grinder thread a while back.

Which side of the disc do you work on? The upward or downward moving side?
 
N.W. Gean said:
Not to hijack but I have a question that went unanswered in my own disc grinder thread a while back.

Which side of the disc do you work on? The upward or downward moving side?
Click to expand...

Downward.

I only use both sides when making a long straight spine, another reason to get a 12".
 
Oh man... It’s starting to sound like the answers to my questions is: No definitive answers. Lol
 
Just got the 9" Trugrit. Mainly for folders and such, but happy with it so far.
 
I'll say this... Whatever you get, make sure you have a good dust collection system! When flattening scales on my disc sander it creates dust like no ones business, even with my shop vac on it lol
 
REK Knives said:
I'll say this... Whatever you get, make sure you have a good dust collection system! When flattening scales on my disc sander it creates dust like no ones business, even with my shop vac on it lol
Click to expand...

That's something I really need to look into soon, but I have a bit of time. We're waiting for our house to be built (permits are a PAIN), so right now my shop space is ridiculously limited. Anything I can do with hand tools is done in the shop, and anything that needs power tools or heavy sanding is done outside. Outside I'm just using a shop vac with a hepa filter, disposable coveralls, and a 3M 7500 mask with 60926 P100 cartridges. I'm going to be cutting a ton of sensitizing wood soon (african blackwood, desert ironwood, and cocobolo mainly), so I'm wanting to step up to a PAPR system and recently sent Stacy E. Apelt - Bladesmith Stacy E. Apelt - Bladesmith a message about it. :)
 
I have a $40 5" from Menards. Its variable speed from 0 - 3200 rpm. It has dust collection for your shop vac and has a very precise workrest and miter. It is absolutely perfect for handle making. Particularly folder handles. I also beveled the disk edge on my mill and use it for dressing up the tang notch in slipjoints. I bought it when I first started doing recovers and have felt no need to upgrade as I've transitioned into my own custom builds.

I was talking with Brad Jansen recently, he runs the same unit and we were wondering if you reversed the wires for the motor if it would run the opposite direction? Next time I get to Menards I'm gonna pick one up and try it. If it goes poof I'm out 40 bucks. If not I have a forward and reverse disk sander that is full variable for $80. They are also pretty small so together they would take up about the same space as a single 9". Then you'll also have more money available for the more important tooling like a 2x72 and a mill. My mill is far superior at making perfectly flat scales from micarta and wood along with being the centerpiece of my slip joint making knife shop.

Another suggestion I would offer now that I have the benefit of hindsight is there isn't much a 2x72 can't do in a shop these days. esp. Now that most have full tilt horizontal. My money would go there first over a high end disk. Then, down the road you can put a disk together for a lot less money than buying the whole package at once. For instance you can source the same motor your 2x72 runs on for a disk build, buy a chassis and work rest for it. Get the disks you want and use the same vfd your grinder is running off of. It'll still be expensive but I've priced it out and it still comes in at about $400 - $500 less than buying it all at once from a retailer.

Bottom line I guess is, at least in my experience a disk is important but it's not that important in the grand scheme. I'd rather put the big bucks somewhere else and spend less on my disk sander but that's just me and my 2 cents.
 
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