powered grinding (not sharpening(?))

I was using a fresh belt and moving the blade back and forth. I don't think this was related to abrasive wear, but it could have certainly been related to lack of technique. The belt is not tight against the platen, so that could have been the problem as Prometheus pointed out. The belt sander is really fast and mine is pretty loud, so I found it a little intimidating. Keep in mind that you can put your own custom platen on the sander if you want a hollow grind or if you want to try to make a slight high spot. I suspect that if I had tried all these things, then my $100 Ryobi sander, which is very similar to the Delta, would have work fine.

My theory here is that with a 1" belt and a 2" blade, you can put the belt in the middle of the blade and grind away more material in the middle of the blade to compensate for not removing material at the edges.

Yes, that was my thinking as well and is why I got a 4" instead of a

1" belt sander. I haven't tried a 1", so I can't compare.

The main thing to keep in mind with the belt sanders (and possibly the grinders) is that using those tools is a pretty "rough" operation. Basically you are just trying to get the bevel close and then clean it up by hand. One reason I have been investigating hand grinding techniques is because you can put the blade in a honing guide and get a more accurate bevel. That seems to be true for me, it is just slower than the power tools. That said, the Robert Sorby belt sander that you provided a link too looks really good. If it were available in the US, I would definitely consider it.

On other thing I forgot to mention is that you could look into a hand crank grinder. There are many pretty many for sale on EBay. There used to be a company called Prairie Tool that made them, but I am pretty sure they are out of business. You might also be able to make a grinder. Lee Valley sells mandrels for this purpose.

If you are really trying to save money, I'd really look into a course silicon carbide bench stone and give that a shot. No matter what you try, I think it is important to just stick with that method until you learn to be proficient at it. (I wish I could follow my own advice.)

Mark

Reply to
Mark Wells
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Every shop needs a good bench grinder. Toss the junk wheels that come with the cheap chineese import and get two wheels a fine and a medium.

Now get yourself a wheel dresser.

The machine comes with a tool rest, and you can make a bevel guice from wood.

With the bench grinder you are knocking down the bulk of the work, not creating the edge. After you get close on the face of the wheel you can cheat a little and side wheel some of the kollow grind out of the blade.

The closer you get to a sharp edge, the quicker the edge will heat up. Since you know this, you give the blade less time and pressure as you get closer. Dip in water often. It is really not that tough to do. If you are worried about it buy some cold rolled steel in the approxamate size of your chisels and practice with that.

In the US, you can set yourself up the way I described for about $160, cheaper if you can buy a used machine. Don't skinp on the wheels.

Let me point out that in every machine shop the machinists quickly learn to sharpen their drill bits by hand on bench grinders, and that tool steel is not much different than your chisel.

Once you are almost there consider the diamond wetstones that are out there. They are now cheaper than ever and they do not tend to get concave like regular stones. They will quickly take the blade to the correct geometry for the final keen edge to be given so you can go back to shaping the wood.

Reply to
Roger Shoaf

Used to be. Now, about 1 in 25 can do this. Forget about a lathe tool, they wouldn't know where to begin.

Reply to
CW

Do you know how durable diamond stones are generally? I had a very concave

50+ yr. old sharpening stone from my Dad, out of sentiment more than need I went to great lengths to flattened it.....In the process I seem to have removed the diamond particles from a coarse diamond stone....I also did a number on a 10inch sanding disk and 4inch sanding belt etc.....Obviously the old stone now probably 1/2 original (when new) thickness "wins" on durable except for the former concave part...Dad mostly used it for decades to do his pocket knife..........Also is there any way to determine if a "old" stone is a water stone or a oil stone? He generally used oil. Or what grit a old stone might be? Rod
Reply to
Rod & Betty Jo

Are you sure that you "removed the diamond particles"? Diamond stones go through a "wearing in" process.

If it's an old stone and not from Japan or that vicinity then it's almost certainly an oilstone, might be an Arkansas stone or a Carborundum synthetic. Arkansas doesn't have a "grit" per se, it comes Washita, soft, hard, surgical hard in order of fineness. Can't really tell Washita, soft, or hard from looking at them, surgical hard will usually be black or translucent.

Reply to
J. Clarke

That's a little pessimistic, CW. Most of the guys I know can do it, even when there is a sharpening rig right at hand that makes it a somewhat less important skill.

Reply to
Prometheus

So twist drills have various tip angles for various materials; Wood, non-ferrous metals, hardened steel, whatever. Someone worked out that the angles (118 degrees, for example) were the "best" in some sense. Efficiency of drilling, drill life, clean cut, I dunno.

My question is, just for grins, would you sharpen a bunch of drills for us and measure the variance in grinding angle among them? I'm guessing you'd get a bell curve around the optimum. Have one of your workmates who "can't" do it by hand do a bunch and then measure the variance of his batch. Ugh, sloppy, right? But, how close would a reasonably competent machine-shop dude come to "good-enough"?

Reply to
Australopithecus scobis

When I started in a machine shop I got probably close to 100# of dull bits to sharpen. My instructions were to come get the boss when I felt confident about that part. 3-4 hours later he handed me a bushel or so of mixed nuts and machine screws to sort.

Ahhh ... those were the days! ;-)

Bill

Reply to
Bill in Detroit

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