PDA

View Full Version : sharpening carbide circular saw blades



spinrow
12-05-2011, 09:07 PM
I have several small circular hand saws with carbide blades from 4 3/8"to 6" in diameter. Finding replacement blades use to be easy but now can't find them in the usual stores. This got me to thinking about having the blades sharpened but can't find anyone to do it so wondered if I could do it? Has anyone had any experience sharpening their own carbide saw blades and what all is involved and is it feasible? Thanks Paul

sasquatch
12-05-2011, 09:17 PM
Not sure were you are located?

Anyway the 4 3/8 diameter blades w/20mm center hole are still available from "Somona" that,s an importer from Vancouver, BC.

I got some not long ago, 24 tooth and they were about $5.00 each. Cheap!

bandmiller2
12-05-2011, 09:24 PM
Spinrow,if your talking about skillsaw framing blades I've done it using a green wheel and a bench grinder.I'am not claming great precision but they sure cut like new.Just follow whatever angles the tips were ground to. Frank C.

Gunney
12-05-2011, 09:43 PM
It is feasible. How easy it is depends on what equipment you have. Assuming the carbide tips are not chipped, you really only need to grind the faces of them. If they are chipped very much at all, however, you'll need to grind the tops (very slight chips) or braze on new tips, in which case it becomes less feasible without fairly good equipment. Anyway, assuming they are not chipped, just dull, the very first thing to do is clean them very well using whatever you have that will dissolve the gunk built up around the teeth (oven cleaner works well). If you only have a few blades and they have a fairly low tooth-count, you can actually just tough them up with a hand-held diamond file. That gets old very quick, though, if there are very many teeth to grind. The best thing to use to sharpen them is a diamond grinding wheel. You want one with a very thin profile where you are grinding with the face of the wheel (http://www.universalsharpener.com/grindingwheels.html for example). Next you need to figure out how you are going to hold the blade so that the face of each tooth is parallel with the face of the grinding wheel, and how you are going to index from one tooth to the next, so that you get a consistent grind on each face. Check the blades you want to grind for the hook angle, you'll want to match that, and it may be different for each blade. There may also be a rake angle, but that is more uncommon for wood-cutting blades. If there is a rake angle, the angle will alternate from one tooth to the next, usually every other tooth, unless it is a triple-chip grind, where one tooth will rake to the left, the next be a flat raker, and the third rake to the right. Once you have a reliable means to hold the blade such that the tooth face is properly oriented to the grinding wheel, and can index it from one tooth to the next, then you only need to grind very lightly to get a nice new edge on the top of the tooth. The actual process is much simpler than setting up to do it. The setting up can be quite involved, depending on how good and how repeatable you want the results to be. In my opinion, the machines they sell specifically for sharpening carbide circular saw blades are way overpriced, but if you have very many blades to sharpen, you will probably want to duplicate the same sort of setup they use. Hope this helps.

Patrick

JoeLee
12-06-2011, 12:03 AM
I've done it with my KO Lee T&C grinder. Once the initial set up is complete the actual grinding process is a snap. It's not something I do on a regular basis.
As Gunney stated all that is needed to be ground is the face, that takes care of three edges. I just ignore the minute chips on the tops if any to keep the OD the same all the way around.

JL........................

WGonzalez2
12-14-2011, 10:08 PM
Here is a very crude method but it did work for me.
I was at the cottage for the summer, learning how to make kitchen cabinet doors and learning how to use my table saw for the first time. So I did not know if the problems was the blades, the speed, the wood or me.

I improvised a jig with hard wood the best I could and mentally made a plan to make a "metal" jig this winter at home where I have more resources.

It did the job with the Dremel tied down to a "slider" piece of wood rubbing against another piece of wood as the "limit" for the cut. The wheel was a Harbor Freight 1" diameter or so ($5 for a set) diamond impregnated. The rest is all chunks of wood with a 5/8' bolt as arbor/blade-holder.

The wood holding the Dremel is held against the rectangular wood strip and I controlled the depth of the cut just with a little pressure forward.

I used a very crude "stop" to "Index" and utilize the same tooth I was going to dress with a piece of bent rod with wood "bushings" The whole contraption is hilarious but it did the job well. The blades came better that new (there were chip imports) and during the process I discovered some other factors that hindered my progress.

Youtube have some good videos of commercial machines that can be utilized as base for the design.
Wilsonhttp://i124.photobucket.com/albums/p1/electronmini/Sharpening001small.jpg
http://i124.photobucket.com/albums/p1/electronmini/Sharpening_006small.jpg
http://i124.photobucket.com/albums/p1/electronmini/Sharpening_003Small.jpg

Rosco-P
12-15-2011, 08:46 AM
Horrible Freight has or had a circ. saw blade sharpener. Was recently on sale for around $60. Grinds the face, but not provision to joint the teeth. Like most chinee machines, they are a"kit" and could be the foundation for a saw sharpener with some modifications, tuning-up and the correct wheel.