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StumpyNubs' Blue Collar Woodworking #7 ( http://lumberjocks.com/StumpyNubs/blog/27256 ) inspired me to try his idea of using MDF discs and buffing compound instead of glass platters and sandpaper on my WS3000.

I found some 1/2' MDF in the shed, so I screwed a face-plate to a piece of 2X, turned it round, then drilled a 7/8" hole in the center while it was still on the lathe.

I took the blank off the face plate, drilled a 5/8" counter bore on the backside and pounded in a 7/8" hex bolt.

I cut a piece of MDF about 6 1/2" square, knocked off the corners on the bandsaw, and mounted it on the lathe.

Note that the spindle on the WS3000 is actually 12mm. My local big box doesn't stock metric bolts that big, so I started with the 7/8" bolt, turned the MDF blank to size, then took the MDF disc to the drill press and bored the hole out to 31/64".

Also, if you turn MDF discs on the lathe, be advised that, if the tools you use were not dull when you started, they will be when you are done … MDF blunts the cutting edges.

-Gerry

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I made mine by just cutting them out on the bandsaw and sanding to the line of the disc sander. They don't have to be perfect because they don't spin that fast.

To mount them on the Worksharp I drilled 1/2" holes through them, but also had to make a bigger hole half way through for the knob to fit in because they are thicker than the standard discs.

The buffing compound I use came from Sears. Craftsman has it on the website too I think. Harbor freight also sells some pretty cheap.

Of course, all those MDF discs need a stand to hold them in…

 

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Gerry, I know that you are a very nice guy about you make some disks for me I get you the 12mm nuts.
Does any one know what is equivalence between the grit and the color of the different polishing compound that HF sales.
I could not find a thing on HF website.
Thanks

By the way HF is 25% off tomorrow

I was reading a little bit about polishing compound.
Am I correct to say that the color does not indicate a grit but the materiel that the compound is made for?
 

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Turning them was probably overkill … but I'll go for just about anything that involves using the lathe!

The bolt in the knob on my WS3000 is long enough that I can get a couple of turns, so I can use both sides of the disc.

-Gerry
 

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b2rtch- I have tried for over a year to figure out the "grit" ratings on these compounds. The only thing you can do is just try them and see what happens. Actually, I sometimes wonder if the white is finer than the red or vise-versa!

I think if you just buy the HF ones and do some trial and error they should work out just fine!
 

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I have owned my worksharp for a few years now and love it.. I've seen lot's of ideas posted before about disks.. so you can take what I'm saying here to the bank…. Been there done that..

MDF will not stand up… plus it has many other shortcomings..

Use acrylic… It's both stronger, thinner (no problem with the knob holding it), "Dead Flat" and you can't hurt it..
The WHOLE reason they used GLASS was because of the "dead" flatness of the surface..
It is "VERY" important to be "dead flat."

Also with acrylic you can use a spray adhesive for your sanding disks, allowing you to use non P&S paper which is cheaper.

We had this conversation long ago…..

I cut the acrylics on my laser to make both of the disks.. Look at this POST
Although I use CLEAR on my slotted disks you STILL have to slot the disks.. it's pretty obvious why.. so I won't go into it..

From a previous discussion on this topic also:
As far as GRITS…. all that are really necessay are 3… They are sold at LEE Valley.. GRITS NEEDED
The SCARY SHARP people recommend using 15 micron (approx 600 grit) - 5 Micron (approx 1200 grit) And then use the Chrome Oxide $2.20 sheet for a mirror finish.. You can read about what I found here..
MICRO-FINISHING

So what I'm saying is your Stumpy's idea sounds good Gerry but it's been tried already and discussed on LJ's and other sites before… Use ACRYLIC… end of story…....

Check out my new Woody Wood Wacker Video Gerry if ya get a chance..>>>> Woody The Wood Wacker
 

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David,
Ok but whee do you buy acrylic and which kind to buy and if (very unfortunately) you do not have a laser machine, how do you machine it?
 

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@ Bert.. Any lumber store sells acrylic sheets..just ask.. used for window replacement..Home Depot etc.. Acrylics cut the same as wood.. so any saw will cut it.. You can also turn it for round on your lathe with Excellent results..
Cut it out rough on you bandsaw and chuck it onto you lathe.. "Make sure you mark center" after you true it up for round (don't touch the surface of the disks, just the edge) so that you can take it to your drill press and use the right sized whole cutter for you center hole..
It comes in various thicknesses.. I used 3/8" you could use 1/4" and stick them together if you wanted..
 

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I have about 10 glass disc for my work sharp so it's to late for me to try a different kind of disc, but I think Stumpy's and David's ideas are pretty darn creative. That looks like a pretty cool stand for your work sharp Stumpy. Your disc making turned out very well Gerry.
 

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Thank you David and Happy New Year to you
 

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Yes Jim.. I'm not knocking Stumpy.. it's just that it's already been tried is all.. He did make a nice stand.. for his.. Mine stand is a little different but it's nice to have everything all together..
You did a GREAT job Gerry.. if you need more disks though give what I'm saying a try is all..
 

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David,
Are you saying that green, white, and red buffing compound will stick to the face of the acrylic disks like it does to the MDF disks?

Gerry,
Your disks look good and the information is appreciated.

john
 

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Hi John…
Just adhere a thin buffing pad to the disk and use whatever grit you want..

Look at this link and see how they did it.. BUFFING COMPOUNDS

You do not need all of the grits they talk about with their system..
Use the ones I posted above.. and you won't be dissapointed..
David
 

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I'v been eyeing and considering the WS3000 and comparing it with other edge sharpening systems. You guys made up my mind for me. THANX ! ! ! GREAT INFO TOO, GUYS.
 

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If this works it sounds great but does the MDF disk stand up to use? I would have thought that it would wear away pretty quick resulting in a non-flat surface. Can anyone who has used these MDF disks comment on this?
 

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Ok, so I just did a little touch of math.

A 49×98 sheet of MDF will ideally yield 126 6" discs. So what's a sheet 1/2" MDF go for? Let's just say $30 to make things come out a little closer. That's about $0.25 / disc. For that money, glue a piece of sandpaper to each side and toss it in the trash when it's used up. You can go through a whole lot of MDF dics for $20.

I would wager a year's salary that a 6" disc of MDF is just as flat as those glass plates within a 0.001". I would also guess that they may be as close as a 1/2 thousandth from each other. Now put a piece of sandpaper on it, which in it's own design, isn't flat or it wouldn't work.

We're not talking about a piece of glass that has been polished, just a generic piece of float glass. Now if you're using you WS300 to make telescope mirrors, then MDF isn't going to work but neither would a WS300.

The nerdy stuff:

Assume an 1/8 kerf
49" / 6.125" = 8
97" / 6.125" = 15.84

8*15.84 = 126.7
 

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LOL OK.. Make them out of MDF.. I only post suggestions.. Maybe once you've tried it your way you might want to try it using acrylics??.. once your 126 run out.. :)
@Jim.. Your RIGHT..
 

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I would like comments from Stumpy, Gerry, or anyone else as to how the MDF disks hold up to your hobby sharpening, especially using the buffing compounds.

Thanks David for the information you provided.

john
 

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I am just thinking that we have big/huge hole saws at work that would be perfect to cut these disks.
Hum! I just found me a new project for next weekend.
A question: I read that polishing compound do not actually "cut" as an abrasive would do.
If this correct how do they remove the metal to create a new edge?
Or do we still use an abrasive disk first and then use the polishing compound?
I wish you all a very good, peaceful, happy and safe New Year.
 

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MDF discs hold up very well, in my opinion. If one of them wears out, it's easy and cheap to make a new one. There is a person on LJ's who has been using MDF discs for years mounted sideways on a grinder type motor with polishing compounds and he has never told me they were a problem. I myself have sharpened a lot on my discs, and they are still very flat.

If you were running the blade on a bare disc, that would be another issue. But the polishing compound creates a replaceable layer between your blade and the discs, and the oily binders in the compound lubricate it very well, which also reduces friction and wear.

If you are using sandpaper on the discs, they will never wear out. I use sandpaper (6 inch adhesive backed discs or just cut sheet sandpaper and use spray adhesive) for very course grits like 80 up to 120 for repairing an edge. Routine sharpening is done with the polishing compounds. Even re-establishing a primary bevel (after the microbevel has become too large) is done with the course black compound. I rarely use sandpaper at all anymore.

Acryllic discs would be just fine if someone wants to spend the significant cost of makeing them (when compared to 1/2" MDF). But if you want to use buffing compounds, you'll need to glue something to the acryllic. A buffing pad, as suggested above, may cause the same problems that some have experienced with leather, if can round over the edge as you sharpen. I would use a sheet of paper and some spray adhesive.

Buffing/polishing compounds do remove metal. The course black stuff even causes sparks sometimes.

I do not doubt David's advice is sound and accurate. I just have found MDF towork just fine. I assume they will wear eventually, but they are very easy to replace.
 
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