The Shop > Tools
Making Simple QC Tool Holders
vtsteam:
Just now looking at the jig plan I thought I noticed a mistake. But I'm starting to think the mistake is mine.
I put a lip on the bottom of the jig assuming the tool would be sharpened pointing upwards. The lip is supposed to ride against the back of the grinder's tool rest.
But now I see in the drawing that the lip is at the other end of the jig. I thought that couldn't be right because the lip would hit the wheel between the gap with the tool holder.
But now I'm thinking maybe they meant for us to grind the tool facing downward in relation to the wheel, so they have the lip on the right side.
This might account for my too acute angle on the lathe tool ....
Here's the relevant part of the dwg.
vtsteam:
If the tool is to be ground laying downward in relation to the wheel, it would naturally have a more obtuse angle because of the arc of the wheel. It would also make sense that the wheel diameter wouldn't affect the angle -- I was wondering about that. too.
Finally, a more obtuse angle would strengthen the point, reducing the tendency to break in deep cuts. It would also mean the point didn't burn as easily when sharpening,. And it would be quicker to profile to shape originally. The jig would be easier to use -- pushing down is easier than trying to keep a short bit pushing upwards against the wheel, etc.
So, I'm pretty sure that's what was intended.
As Bugs Bunny used to say, what a maroon!
Nevermind..... :doh:
vtsteam:
Last photo tonight, showing how the compound 12 deg angle is achieved. The side face of the tool holder is beveled 12 deg, and then the tool channel is let into that at 12 degrees.
The button head screw tends to roll the tool upward slightly when tightened. I'm going to add a thin washer to prevent that. I noticed one in a photo at the website previously mentioned.
The tool bit was a broken piece I happened to have. Guess I'll be making a new one tomorrow and a new sharpening jig....
black85vette:
You can also slightly round the edge making the point so that it is not as sharp.
Here is the one I made to mount directly on the Atlas/Craftsman 12";
IMG_5874 by black85vette, on Flickr
And one I made for the 4 way tool post that will hold round stock to make an elliptical cutter:
IMG_5875 by black85vette, on Flickr
SwarfnStuff:
Hi Vsteam,
Your tool pictured looks way too steep. So I went to me shed thinking I could easily find the paperwork that came with my tangential tool from Eccentricengineering.com.au here in OZ. I know the angle is stated in said paper work. Alas I must have put it away carefully (never to be seen again) :Doh:. I seem to recall a mention of 28 deg and when this is inserted in the holder with 12 deg it would come back to 16 deg. You will also grind less of your tool steel off although grinding a new piece still is a fair grinding job even with the 8mm stuff I use on my 7x lathe.
Cheers,
Swarfnstuff
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