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Killer...thanks for sharing. Does anyone know if you can buy a jig to sharpen 20 inch planer blades?Hello, my first post here...
Few months ago I was looking for DIY methods for planer knives sharpening but didn't find any better that I was already using. Grinding is actually easy, getting final sharpness was my problem...
So, as I was reading how people here sharpen their blades – glass plate and fine grit sandpaper... nooo too much effort and if there are minor dings in cutting edge.... - and some people grind their blades freehand against grinder.... - nooo ... I really need that perfectly straight cutting edge!
So here is how I resharpen my blades.
(I know there are better tools which will give better result but currently these tools are what I have to work with...)
- Take bench grinder and screw it down to your workbench. Make sure grinder isn't wobbly/vibrating when in use. It's good to have underpowered grinder (mine is 150W with custom made plywood mount) otherwise you !will! overheat cutting edge.
- You will need grinding jig, look at the pictures, it will take around 1-2 hours to make one but it's worth it.
- Use C-camps to attach the jig to workbench. Its better to use certain size C-clamp not the adjustable C-clamp, because adjustable ones can work themselves loose when grinder vibrates.
I grind blades with to angles. First I give it quite sharp angle, have not measured it so i wont give any numbers, later Ill just change jig's angle and make cutting angle quite blunt, therefore cutting edge will last longer, otherwise cutting edge might be too thin and folded backwards. Getting the angles right comes with experience I suppose, well I am still learning it...
- Take something with straight edge and clamp it to jig. Adjust slider fence (that straight edge) so that grinding wheel just slightly touches blade. Test both blades, one might be higher than another. Holding the blade on jig and hand rotating the grinder can leave marks on blade to check if the grinding angle is OK.
- So start grinder and let the sparks fly... When grinding you must remember that too much pressure on blade ends with burnt blade, that we don't want. Take off minimal amount of material in one pass, so that the wheel barely touches the blade. This step is most time consuming and most important. Go slow! Grinding is ready when you can feel ridge when sliding thumb crossways over back side of blade.
- Buffing. This is actually the step why I am here. I have not figured out a good way to get ground blade fine sharpened, so I am open to ideas. I have tried honing on waterstone but the stone I have is really, really fine. Maybe I should get one diamond stone for planer blades only... Buffing wheel I have is made out of plywood (another DIY) and thin layer of leather, bit off balance but works... Buffing is done until that ridge that you felt with your thumb is gone. I think you should not buff backside of blade I have done it but not good..., so buff only the surface you ground.
- When blade starts to cut hair I usually consider it ready. Put blades in planer and do a test run.
So this is how I have sharpened my blades for few years now...
Grizzly has a 20" sharpening machine for around $520.00. Used to be $319.00 when I got one from Trend.Killer...thanks for sharing. Does anyone know if you can buy a jig to sharpen 20 inch planer blades?