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MDF for honing?

J

Jim Stoppleworth

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Apr 7, 2005
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Location
Saginaw, Michigan
In Alan Lacer's video he shows using a homemade MDF wheel for honing his skews.
He doesn't address what grade MDF in the video works best. Anyone know which grade or anyone who uses an MDF wheel dressed with white diamond
to hone skews?

Jim
 
Was aware of different densities, thus Medium Density Fiberboard as opposed to High or Low. If it is to be charged with a compound, and I use the green Chromium on hard felt or leather, it should not interfere with their action. May not get what you want. We're talking about glue, bark and sweepings, after all, and I have a feeling that they don't grade the particulate stuff that well. Might be a lot there to leave scratches rather than a clean bright stropped edges.

Shouldn't make a difference with turning tools, but I wouldn't strop my carving tools on it.
 
MM,

Lacer said in the video he was given the idea by a carver.

In my pile of what was sold to me as MDF I have at least 3 different average particle sizes and thus, I guess, densities. I didn't know and obviously the borg clerks didn't know there were high, low and medium densities or different grades.

To make the wheel I chose the one with the smallest particles thinking along your lines it would leave the smallest scratches. BTW the wheel turns away from you and is charged.

We'll see how it works. I'm still hoping to find someone here has tried it.

Jim
 
I have not tried this method, but I work with MDF quite a bit.

I work in a cabinet shop and have done a little research on MDF for our spoilboard on the CNC router. (As well as using it in cabinets!)

There are three major divisions in the density of fiber board, as MichaelMouse points out.

Low Density Fiber (LDF)
Medium Density Fiberboard (MDF)
High Density Fiberboard (HDF)

(These can also come with a Melamine, vinyl, or veneer, either on one side or both sides.)

There are specific density standards which they must adhere to. I'm not sure without looking them up again exactly what the ranges are. But suffice it to say that the more resin in them the more dense and heavy they are.

There are various grades within these divisions as well. We are currently using a "door grade" from which MDF doors are made. This is a high quality product which machines well and has very smooth "grain" which sands and paints well. You could also use a "molding grade" for a similar finish. Some MDF's don't finish well because the surface is a little rough after machining. It takes a lot of sanding and filling to get it to look good.

(I doubt very much that manufacturers of this product would appreciate our view that it is made from "floor sweepings." They take pride in getting a good material to work with in making this stuff. "Pure yellow Pine" (or whatever species they use) and "only the best" blah blah blah is what you see on their websites... 😀 )

But I would think that most MDF's would be suitable for this application.

Fiberboards are created with a lot of heat, resin, and pressure. The outside surfaces are usually more dense and smooth than the rest of the material in my experience. The particles also need to be quite uniform so as to meet the standards. So even if there are variations in the particle size, there is still a smooth surface because of quantity of glue on the outside surface. I instruct my CNC operator to flycut at LEAST the first .020" (if not .050") off of each side of the spoilboard to get good flow through it. Indeed, it is standard practice in the industry...

I would think that the abrasive that you charge it with would do most of the cutting/polishing action rather than the MDF itself. The reason for using MDF is that it is uniformly flat, stable, and inexpensive.

These are not to be confused with Particle Board which is used with Laminate countertops. Particle board can also come with Melamine (a very thin laminate) surfaces, one or both sides. You can easily see the chunks of wood in this material. It is quite inferior to what we call MDF. I am wondering if this is what you got instead of MDF. 😕
 
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Like most comparisons, it often boils down to alternatives. Hard felt or leather are excellent alternatives, easily available, and at low risk. Since turning tools do not require the same standard in an edge, the charged MDF may do just fine. As I keep carving tools, I prefer the alternatives.

Free advice on buffing devices - keep them far away from grinding devices, no matter how inconvenient it might be to walk from one to the other. Wipe the tool off with paper towelling off the hone or grinder before applying it to the buff, as well. Careful of the edge! You really don't want renegade pieces of metal or grit in your buffer surface or embedded in the wax that helps hold the charged abrasive to them.
 
underdog said:
I would think that the abrasive that you charge it with would do most of the cutting/polishing action rather than the MDF itself. The reason for using MDF is that it is uniformly flat, stable, and inexpensive.

These are not to be confused with Particle Board which is used with Laminate countertops. Particle board can also come with Melamine (a very thin laminate) surfaces, one or both sides. You can easily see the chunks of wood in this material. It is quite inferior to what we call MDF. I am wondering if this is what you got instead of MDF. 😕
Click to expand...

Jim,
First thanks for the explanation of LDF,MDF, and HDF.
OK -- Now I'm getting confused.
Would it be wrong to assume that a borg couldn't advertise "particle board" as MDF?
(I have some particle board from years ago that I used as shelving on top of 1X2 framing and can see the great difference in particle size and density.)
I'm a newbie -- I'm trying to get to sharp tools by learning as much as I can about the sharpening process. Using videos, books, internet forums, and machinist friends I'm making some reasonable progress in getting much sharper tools than when I started. It's making a huge difference in my turning's quality of unsanded finish. I saw this as a way after I had a good edge to hone that edge before turning. Then when I want to touch the edge up at the lathe I could use a diamond hone. Do my process steps make sense?

Jim
 
Jim I built a sharpening system several years ago using MDF. I just went to the store and bought whatever they had. I didn't know they had different grades and I couldn't buy it at my local store anyway.
I had used a hard felt wheel but needed something to sharpen different shaped carving tools. I took a short carving class at John Jordan's and he had one made from MDF and he just turned different shapes into the wood to accomadate the different V gouges and such. I tried it and it worked well but at the time I wasn't doing much carving with had tools so I gave it to a friend.
Now I'm looking at setting up a permanent carving station and will probably build another one for my carving tools.
I don't feel that it's needed for turning tools with the exception of the skew. I just got an e-mail from a fellow skew person and he sharpens his with an MDF disc mounted in his drill press. He charges the top surface with the green sharpening stick.
 
MDF Honing

I had been intending to setup a power honing wheel in the shop for a while now, this thread kind of nudged me to get it done.

I had an old delta 6" grinder sitting idle. The only thing I used it for was grinding lawnmower blades and buffing out the odd rusty tool. So I took the grinding wheel off, cut some 6x8 MDF squares to use as spacers to get the wheel up off the bench. I also flipped the motor around on the base so the power switch is in the front, but the wheel spins away from me.

The shaft on the grinder is not long enough to accommodate two 3/4" MDF discs together, so I did two 1/2" MDF discs. The MDF is the standard stuff that you get from Home Depot in the 2x4 sheets. I stuck the discs together with 3M 77 contact adhesive. I was thinking that other glue could have some effect on whatever I was honing.


I charged the wheel with some white diamond and was off and running. The power honing process is quick and effective, but somewhat less accurate than my slower leather wheel. When honing a skew or gouge freehand you need to take care that you don't present the cutting edge before the trailing edge of the bevel, it rolls over the edge really fast.


It is the only thing I have in my shop that spins fast and away from me, it would be a bloody event if in a momentary lapse I contacted the wheel in the lower front quadrant with a sharp tool. It would likely come back at my head. I will be putting a big sticker on the motor with an big red arrow indicating the direction of rotation. A will also be fabricating a guard for the naked MDF wheel to prevent contact with the lower front of the wheel and most importantly I just don't trust that the MDF will never eventually break appart.

It doesn't take a lot of practice to be able to get near the "scary sharp" kind of edge that we hear about. After honing I was able to take a piece of oak about 18 inches long and let the weight of a skew take a 1/4 inch corner off the wood for the entire length with not much more than the weight of the skew being the only force applied.

Happy honing!

- Jeff
 
jastop said:
I charged the wheel with some white diamond and was off and running. The power honing process is quick and effective, but somewhat less accurate than my slower leather wheel. When honing a skew or gouge freehand you need to take care that you don't present the cutting edge before the trailing edge of the bevel, it rolls over the edge really fast.
It doesn't take a lot of practice to be able to get near the "scary sharp" kind of edge that we hear about. After honing I was able to take a piece of oak about 18 inches long and let the weight of a skew take a 1/4 inch corner off the wood for the entire length with not much more than the weight of the skew being the only force applied.

Happy honing!

- Jeff
Click to expand...

Bascially just want to do skews and scrapers. Can't wait to get the MDF wheels on the grinder!

Can a person do the similiar thing with leather attached to the MDF wheel?

Jim
 
john lucas said:
Now I'm looking at setting up a permanent carving station and will probably build another one for my carving tools.
Click to expand...

Try a great old carver's trick of cutting the profiles of your tools into eastern white pine or leather, and using loose abrasive and oil for honing, then stropping with the charged wheel or another charged block with the profiles in them. Lee Valley sells various grits, I know.

Nice thing about this method is you can have inside profiles cut right next to the outside for removing the wire edge left by the stone.
 
Another use for the MDF honing wheel...

I managed to get my tool rest looking pretty messy yesterday. I was rough turning some big and out of round pieces, the little bit of tool bounce scratched it up the rest pretty good. On top of that it was oak, so the acidity turned the rest a nice rough rusty brown.

After I was done I used my new MDF wheel to "hone" the tool rest. It went really quick, much faster than the file and stone I usually use. It looked really pretty, but more importantly the surface was glass smooth and allowed for very steady tool movement.

- Jeff
 
underdog said:
These are not to be confused with Particle Board which is used with Laminate countertops. Particle board can also come with Melamine (a very thin laminate) surfaces, one or both sides. You can easily see the chunks of wood in this material. It is quite inferior to what we call MDF. I am wondering if this is what you got instead of MDF. 😕
Click to expand...

Went to the borg today on another mission and looked at their 2x4 MDF. It doesn't resemble mine. Mine which I have determined is a better grade of particle board. My apologies to all for my 63 year old newby stupidity.
Got myself a 2x4 sheet and am in the process of making the wheel as I type.

Jim
 
jastop said:
I had an old delta 6" grinder sitting idle. The only thing I used it for was grinding lawnmower blades and buffing out the odd rusty tool. So I took the grinding wheel off, cut some 6x8 MDF squares to use as spacers to get the wheel up off the bench. I also flipped the motor around on the base so the power switch is in the front, but the wheel spins away from me.
Click to expand...

I have a couple unused grinders sitting around as well, 6" and 8" and have already thought about turning the 8" into an MDF honing station like I saw in the Lacer video. But what about the speed? These grinders are full speed 3,400+ rpm guys. Isn't that too fast?
 
Grinder speed...too fast?

My 6 inch is a 3450 rpm. And yes ... it feels real fast. And I don't know what speed grinder Lacer uses.

After a few days of use the MDF wheels on my grinder don't show any stress cracks, or even tears near the arbor. But I also won't be standing directly in front of the wheels either. I have an innate fear of anything in my shop moving that fast. This includes router bits, grinding wheels and table saw blades.

Why do I have fear?.... My recollection( and it could be wrong) is that you can take the RPM multiplied by the Diameter multiplied by 0.003 and you get the approximate surface speed in MPH. So our 8 inch MDF wheel is moving 80+ MPH. Getting hit by a pound or so of anything moving that fast has to do some damage.

- Jeff "Always wearing a full face mask" S.
 
Honing speed...

Here is an answer to what speed Alan Lacer uses it... looks like 600-1000 RPM.

I found it in a PDF that looks like a reprint from an AAW article. Here is the link ... http://www.alanlacer.com/pdf/%20Honing.pdf

Should we be stepping down these fast grinders to a slower wheel speed with a couple of pulleys and a belt? Or will the MDF stay in one piece at this speed?

Jeff
 
jastop said:
Here is an answer to what speed Alan Lacer uses it... looks like 600-1000 RPM.

I found it in a PDF that looks like a reprint from an AAW article. Here is the link ... http://www.alanlacer.com/pdf/%20Honing.pdf

Should we be stepping down these fast grinders to a slower wheel speed with a couple of pulleys and a belt? Or will the MDF stay in one piece at this speed?

Jeff
Click to expand...

Good question Jeff. Since Lacer says in the article,"I find that high speed is not necessary, I prefer 600-1000.", I'm thinking he's not ruling out high speed just prefers a slower speed. I see the problem with the higher speed is that we can round over the edge quicker as he points out a paragraph or two later.
My personal feeling is the MDF will hold together at the high speed, but I'm definitely no expert.

Jim
 
honning using MDF wheel

The MDF that I used came from Home Depot. The particle size appears to be small. I was unaware that there were differnt types of MDF. I laminated two pieces of 3/4 in MDF using one of the Titebond glues, ( I dont not remmember which one) The diameter of my wheel is 8 in. which is the same diameter of my grinder. I use Zam as an abrasive. Works great but as stated above it's real easy to roll the edge. peter kolb
 
MDF honing wheels

peter kolb said:
I laminated two pieces of 3/4 in MDF using one of the Titebond glues, ( I dont not remmember which one) The diameter of my wheel is 8 in. which is the same diameter of my grinder
Click to expand...

I'm finally getting on with this project. Have the grinder stripped and the motor mounted backwards on the pedestal to effectively revese the rotation. I have two 8 1/2" x 3/4" MDF discs glued and clamped.

My grinder has a 5/8" shaft so I was thinking I'd bore an appropriate sized center hole with a forstner bit then ... what? 😕 Buy a big honking 5/8" bolt and nuts, cut off the head, mount the discs on the bolt between the nuts, chuck up the solid end of the bolt?

How did you guys turn your MDF discs round?
 
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