Years ago, I bought a bench grinder at a discount import tool and surplus store that predated Harbor Freight stores. I was working on a very tight budget but I wanted a dedicated grinder for sharpening chisels and drill bits. This grinder is rather heavy with a cast iron base and the store owner let me take it out of the box to confirm that it ran smooth. It ran very smooth, in fact, and twenty dollars later I was at home repairing my chisels.
All I have ever used this grinder for is sharpening tools and I have only ever had one complaint about it. Chintzy tool posts.
The factory posts on this machine have never been good and I was never able to use them to any purpose. Where this was not a problem up to now, as I get older, (that is to say blind and arthritic), I find that I have a hard time holding the tools at the grinder correctly and I have not been doing a good job with them at the grinder, which means a lot more time spent honing things.
This week, I decided to fix this problem. First I shopped for a better grinder finding these items: http://www.wenproducts.com/store/bench-grinder/8-inch-Slow-Speed-Bench-Grinder-Item-4286 , http://www.amazon.com/DEWALT-DW758-8-Inch-Bench-Grinder/dp/B0000224J4/ref=sr_1_4?ie=UTF8&qid= 1463002504&sr=8-4&keywords=tool+grinder , http://www.amazon.com/WEN-4276-6-Inch-Bench-Grinder/dp/B00LPFIPQ0/ref=sr_1_1?ie=UTF8&qid=1463002504&sr=8-1&keywords=tool+grinder , one of which I may still purchase. Giving it some thought, however, I decided that I was not ready to give up on my old Hoteche (made in someplace called “Chine”) bench grinder. Removing the old tool posts, I decided to see what sort of improvements I could come up with in my workshop. Honestly, I never even thought of purchasing an aftermarket tool post. That is just not my style.
First I needed to turn the bottom forward shroud mounting screw around and replace it with a flat head machine screw, countersinking the hole in the inner shroud so that the screw sat flush.
That done, it was time to start fabricating the new tool posts. I chose to use aluminum for much of the build because I can process the material easily in my woodshop. If you hav not done this before, I should caution you to read about cutting aluminum with your wood working machinery before you try it. Negative rake saw teeth and properly held/clamped/controlled work pieces generally produce more favorable results with less potential for damage and injury.
Because the minimum speed on this woodworking drill press is 750 rpm, I was careful to clamp things well before drilling my holes in the post structure pieces. Certainly, it is fruitless to match drill holes without clamping things properly.
I quickly deburred the holes by hand
Not pictured is a a 10 gauge steel backing plate that I am fastening to the inside of the shroud to act as a stiffener.
I drilled and threaded the 2 mounting holes for the tool posts in the backing plate for 3/8 nc hex headed cap screws.
Here, my phone battery died and I proceeded without the camera. The bottom mounting plate, which mounts to the aforementioned backing plate, is 1/4 by 2 inch aluminum with a 3/8 slot along the length for depth adjustment. This mounting plate has a vertical adjustment slot for the tool post risers that attach on either side with the 1/2 inch nc bolt and wing nut. (I will replace these bolts with carriage bolts after my next trip into the hardware store.) To make the slots, I drilled s series of the appropriate sized holes on lay out, cut out the remaining material with a jigsaw or hacksaw as best suited the task, and filed them to the line with a coarse, double cut mill file. I used 1/8 inch aluminum bar to bend up the adjustable tool rest mounting brackets and fastened the 1-1/2×3-3/4 inch steel tool rest plates to the assemblies with more of the aforementioned #6 machine screws.
I set the tool rests such that I could grind the chisels at 28 degrees. I should note here that once I have hollow ground a butt chisel, I seldom hone it beyond 400 grit on the diamond stone, very occasionally I will take it to 600 grit. Too fine an edge on something like a butt chisel does not hold up and I do not like to have to stop five times a day when setting doors to hone my chisel to a mirror finish on a 6000 grit water stone. I feel the same way about most chisels and plane irons. I will hone carving chisels, paring chisels, and specialty plane irons to 600 or sometimes 1000. With limited exceptions, I hollow grind irons and chisels at 25 to 30 degrees and hone everything between 25 and 35 degrees depending on the steel and my purpose. My preference comes not so much from reading but from training and personal experience. Years ago, Stanley Tool Works used to publish booklets for tradesman with instructions on how to sharpen tools. I have one, it is a good resource. Please reign in your anger if you disagree, as I neither have to sharpen nor use your tools.
Thanks for reading. This was a fun little project that should improve my quality of life immensely.
-- The Constitution only gives people the right to pursue happiness. You have to catch it yourself. Benjamin Franklin