|Belt Sander Sharpener --- My Version|
For all of my flat blades I prefer using Japanese water stones and guides only, I'm not a fan of hollow grinding on a wheel. Yes it's more time consuming but it suits me and my method of woodworking. The only time I ever use power grinding on a chisel would have been for my carpentry chisels that gets into a fight with the occasional nail and loses!
Carving chisels and gouges present a different set of problems. When they're factory fresh, so to speak, the bevel is uniform and occasional honing or stropping keeps them cutting well. As time goes on though the edge will tend to roll over making it harder to slice through the wood. Many times it's desirable to lengthen the bevel or change it slightly to suit your own angle of attack. I've been working on that and for me, getting a uniform bevel by hand has proven difficult. So, back to the web and books to do some research.
In Leonard Lee's book on sharpening he talks about how the belt sander is an excellent but over-looked method you can use to sharpen tools. I used this as a starting point and the more I checked it out, the more attractive it became to me. Lee Valley sells a 1" x 42" belt sander without a motor but there are any number of places that sell a 1" x 30" belt sander starting at $30.00 or so from Harbor Freight to the $400.00 or more range. I opted for one from Enco which looks similar to almost every other 1x30 sander on the market. Before I get into the details of this sander, another thing that makes this concept attractive is Lee Valley's offerings of sharpening belts. Here's a LINK to them, they're reasonably priced and since power sharpening is not an everyday process they will be less costly than buying quality grinding wheels.
According to safe practices, when you're sharpening it's better to have the rotation of the belt going away from you. The tool rest that comes with the sander can't be tilted to a steep enough angle anyway, even if the belt was rotating the correct way. That's why I made this plywood enclosure and bolted the belt sander to the back of it. This way the belt is rotating away from the blade and by coming up with this tool rest I can also achieve the required angles. I wanted to leave enough room on the side to make belt changing easy. Making the tool rest had me doing my share of head scratching! I had the piece of perforated piece of angle iron from some long ago project so decided it would be the base. Knowing that the closer I could get it to the belt the safer it would be is why I notched it out as shown. You can see it better in this picture:
|Parts other than the Housing|
The other parts are a 3/8" all thread with fender washers and a wing nut. Next to the tool rest is a guide that will help keep the chisel square to the belt. It can be bolted through one of the elongated holes so that makes it adjustable. The MDF pieces that are labeled with the angles on them is what I came up with to support the tool rest. Trying to create a pivot point wasn't possible because the distance between the rest and the belt would increase/decrease.
If I "deconstruct" the process of setting it up it may be easier to understand. First of all, the rod is run through the holes:
|Step One: Insert Rod|
As the rod is threaded through, you also thread in the desired angled rest:
|Step Two: 25 Degree Rest Installed|
Push the threaded rod all the way through both of the rests and sides of the box:
|Step Three: Insert Rod Completely Through Unit|
Lay the metal tool rest on top of the angled blocks:
|Step Four: Tool Rest in Place|
Now you can tighten the wing nut securely. Since there is some flex at the ends of the plywood box it's easy to get a good, tight hold. If needed you can also fine tune the angle of the rest to the sanding belt.
|Final Tightening & Adjusting of Tool Rest|
So, how does this all work? Well, so far I've been really pleased but can't give it a full test until I get the sharpening belts from Lee Valley. Using an 80 grit belt I just had to see what would happen. Even though I won't use this on flat edges the chisel on the right is a garage sale item that I use to scrape glue off of projects once it's set up. You can see it has a nice scratch pattern. The two carving chisels are part of a quality, 11 piece set from Harbor Freight which I think set me back about eight bucks!
|Check it Out!|
The question though is: will it cut? Check this out and tell me what you think: