Surface grinding the edge bevel?

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I have my knife blank pretty much all made up, although now I don't want to mess up what I've already accomplished by free hand grinding so I'm thinking about using a surface grinder to set the initial bevel of the blade. I would like to know what angle would be best to grind at, to end up with a high flat grind on 3/16 thick O1 to be used as a hunting/bushcraft knife. Thanks in advance.
 
Here is a table posted by Steven Penner a while back:




Here is a table from Travis Wuertz:

 
If this worked, we would all be doing it. There are several problems here: (1) A surface grinder's movements are linear, but your blade shape is presumably curved. You will be able to bevel a straight section on your surface grinder but not the belly/tip etc. There are pics/vids of the Wuertz surface grinder being used to grind a bevel that illustrate this point. (2) A surface grinder is extremely slow.

As for your angle, if you know the width of your blade and where you want your grind line to be, this is simple trig. Also there are charts you can find with a search.
 
It's been 40 years since I took trig and calculus so I couldn't solve anything more complicated than A sq. + B sq. = C sq. to save my soul. I use Penner's table and it works great. To keep the grind width constant, raise the handle as you come into the tip of the blade.
Tim
 
Grind angle calculators and bubble jigs work fine for hand grinding bevels. A surface grinder would be a poor choice in my opinion. There are variables that your hands can/will automatically adjust for, as tim37a pointed out.
 
Just take the time to learn to grind freehand. The time and steel investment will pay dividends later. Don't rely on jigs or devices until you have a good foundation of freehand technique.
 
If you do get into it, Travis' TW90 is pretty much the standard now for this kind of stuff.

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That's hardened 52100, 0.187" thick. Each side after setup takes 30 seconds.
 
Do you place shims or feeler gauge blades under the top of the magnetic table to make your grinds and is it by trial and error method the first time or is there a calculation. I have been interested in the Wuertz attachment. Thanks, Larry
 
Larry, you do a calculation like what people described above (or use the table) and then grind out some shims to the exact thickness you need. Here's what one shim looks like, then you put a 2nd one in there when you grind the opposite side.

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I second what Don described above. Travis' surface grinder and chart work fantastic. Don, good to meet you at Travis' earlier this year. You make some great kitchen knives!

Eric Fleming
www.flemingknives.com
 
P.Brewster said:
Yes, but it's important to understand that this setup cannot bevel a curved section (i.e. the tip or belly)
Click to expand...

Actually you can start a knife that has a curved section then fade in the belly or tip after the bulk of the work is done. I've seen Travis do it in his shop. it speeds up the process but leaves about 20% of the work to be completed by hand.

Eric Fleming
www.flemingknives.com
 
My blades have a belly. Eric is right; you finish the rest by hand (or figure a different method) but it is a great approach to starting your grind. It results in a solid starting point with a centered edge very quickly.

It was great meeting you too Eric! I enjoyed seeing your press and look forward to seeing what else you may bring to the next event :)
 
This same thing can be done on a regular surface grinder by shimming the magnetic chuck. It can also be done to grind in distal taper. I made a belt conversion for my surface grinder long after I learned to free hand grind so I only did it once out of novelty and used pennies as shims. If I was just starting out it is a viable method.

I think the biggest advantage is that it establishes the bevel for a beginner and it is much easier to tweak the grind or do the belly ect when a flat grind has already been established. However most beginners dont have belt converted surface grinders either so I don't know how many would really do it this way.
 
Well I do have access to a fully equipped machine shop, that's why I was thinking surface grinding but it sounds as though I should do it by hand.
 
Hate to bump an old thread but does anyone have the chart from Travis for surface grinding distal taper or tapering tangs? I can't seem to find it on the web anymore.
 
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