Replies

1. 
   9619 | Feb 05, 2009 08:02pm | #1

   Croc,
   I am sure you will get a lot of good responses on this one. All hand tool users have to grind their plane blades.

   But here is a thought. What do you mean by "Accurate"? I believe if you are close, you are fine. BUT the real question is "close to what"? Well that depends on whether you are planing really hard wood or soft wood or gnarly grained wood. You adjust the angle of the bevel on plane irons and chisels based on what you are about to do with them.

   There are plenty of books on this. An infinity of books and articles on which angles to make for various uses. You might try a search on the Fine Woodworking Website. Actually I was a bit surprised that You asked the question without indicating that you had done any basic research on a question which is as old as planes are.

   A good way to learn how to set up a grinder is to find someone who uses one and have them show you (using your tools, of course). The second best way is to search the web for books and articles on the question. But you'll probably get a lot of answers here on Knots.

   Good luck.
   Mel
   PS I hope you didnt take offense at my suggestion of doing research before asking a question on Knots. IMHO it is a good practice.

   Measure your output in smiles per board foot. 

1. 
   Croc | Feb 05, 2009 10:47pm | #3

   I am aware of the need for different angles for the different applications and even the practice of back beveling is justified in some situations.  I guess what I am looking for is a jig of some sort to get me to the angle I am looking for (within a degree or two) on the first try. 

   I have many plane irons ground at different angle and use those to set up the grinder but this is quite often not accurate enough.  I discover this when I go to my Veritas Mk II for honing.

   Maybe I should just buy about five grinders set up for of the angles I might use.

1. 
   flairwoodworks | Feb 06, 2009 02:42am | #7

   While you're considering five grinders, why not look at a belt sander. Some of the 1" wide versions have nice tool rests.I use my bench grinder for rough shaping and am able to get the angle pretty close pretty quick. I rely on honing guides from there for the proper (and accurate) bevel angle.Chris @ http://www.flairwoodwork.spaces.live.com(soon to be http://www.flairwoodworks.com)

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

2. 
   lwilliams | Feb 05, 2009 09:57pm | #2

   Croc,

   First, dump the slow speed grinder and white wheel. They're slow and the wheels more difficult to dress and true. Get a high speed grinder with as coarse a wheel as you can get. They say there are some new Norton wheels that supposedly grind cool but I haven't tried 'em. The new wheels are expensive and I don't have any trouble doing what I do.

   To set the angle, you need to understand that the thickness of the tool you're grinding actually sets the angle. At the same tool rest setting a 3/16" thick iron and a 1/8" iron will grind a dramatically different angles. The quick way to set the tool rest of a grinder is to have templates on hand. I make sticks maybe 3/4" wide and the thickness of the tools I grind. The end of these is cut or sanded to the desired grind angle and just eyeball the tool rest while holding the template on it and in contact with the grinding wheel.

1. 
   Croc | Feb 05, 2009 10:52pm | #4

   My grinder and wheel work great.  I am impatient and burn blades with the high speed I used to have.  I even used 60 grit wheels to no avail.

   Thanks, for the tip about the wooden setup blanks but I use the same principle with various spare blades ground at the angles I need and I still can't get it right all the time.

   Guess I am just too picky

1. 
   lwilliams | Feb 05, 2009 11:13pm | #5

   Forcing a tool into a wheel is like forcing thick stock into a band saw. You won't get good results. 60 grit is about as fine a wheel as I own. Look for 24 or 36 grit. Grinding is a rough shaping operation, you're not sharpening on a grinder. It only takes a couple passes on a medium India stone to remove the grinding signatures of a 24 grit wheel. Coarse wheels grind cooler and you absolutely have to keep them properly dressed.

2. 
   philip | Feb 06, 2009 01:25am | #6

   Larry has said it all but I can't help reinforcing the fact that proper wheel dressing/conditioning is most important .And the idea that these wheels are to run SLOW is counter-productive. The makers state optimum peripheral speeds on their products for good reason.
   Depending on the type of grinder you have you may get better results by making a tool rest which is independent of the machine itself and removing the existing tool rest.
   But then again all that is useless if the wheel is being used under the wrong conditions.Philip Marcou

3. 
   derekcohen | Feb 06, 2009 05:44am | #8

   Hi croc

   In my opinion, grey wheels are not suited to woodworking blades. The white wheels are much more tolerant of handling high temperatures. But the blue 3X Norton wheels are just the best at this. They are the most friable and least likely to overheat an edge.

   Get the coarsest wheel available - but everything is a trade off - too coarse and you have extra work on your stones. I recommend 36 or 46 grit. Even 60 is too fine. Anything finer is better suited to HSS steel that turners use.

   But the question here is how to set up a grinder for a bevel. That is done via a template. I have an article on this on my website, but it is short so I have reproduced it below ...

   Angle Setting Jig For Dry Grinder

   Here is a jig to set the angle on a dry grinder. It can be made for any angle.

   My grinder set up is an 8” half-speed machine with the Veritas tool rest. The wheel is a 46 grit Norton 3X.

   Adjusting the tool rest for a specific angle needs to take into account two factors, the diameter of the wheel and the thickness of the blade.

   As the diameter of the wheel becomes smaller, it will be necessary to make a fresh jig. The only jig I am aware of that adjusts for different diameter wheels is the Tormek. However the is not enough room to use one on a dry grinder with wheel guards.

   Each time the jig is used, it must account for the thickness of the blade. This is done by placing the blade on the tool rest, and then the jig on top of the blade.

   Tighten the tool rest setting once it is set up as in the above picture.

   The Jig

   View Image

   Making the Jig

   The dimensions are not relevant and may be made any size you please. The jig in the picture will grind a 25-degree hollow.

   Use a blade with a known bevel angle (say 25 degrees). Set this up to grind such that it will create a hollow at the middle of the bevel.

   Now replace the blade with a blank template - the wood - and hollow grind that. This will give you a template to reproduce that angle. Do another for 30 degrees.

   When I calculated the angle for my 8” wheel, I found that a 15 degree angle corresponded to a 25 degree bevel.

   View Image

   Regards from Perth

   Derek

    

4. 
   AdamCherubini | Feb 06, 2009 03:17pm | #9

   I'm assuming you have the wood craft grinder. The tool rests on that machine are really quite bad. I'd like to see someone make aftermarket parts for that machine. I like the grinder, but the tool rests are a joke and the cup washers stink as well. I guess that's the difference between a baldor and a $100 grinder.

   I don't use the tool rests at all. Or at least, not for my tools. I do sometimes lay a finger on one.

   Grinding freehand is not hard to do or learn. I disagree with the premise of your question. I have this little brass angle checker thingy I bought from LV. You get that thing, you put your blade against the stone, you pull it off and check the angle, you make adjustments. It's not hard to free hand grind.

   And I think it's easier to learn when the grinder has a wide wheel (I like it cambered like a smooth plane blade) and when the wheel turns slowly. Larry is in production. He makes plane blades for a living. Philip the same. I assume production wood turners use higher spindle speeds as well. I think the slow speed helps guys who don't do this as often.

   (BTW- the slow speed 8" grinder is 75% slower than the high speed 6" grinder in SFPM...3600 vs 5715fpm. It's not half the speed as far as the tool is concerned)

   I'm guessing you are using your hollow grind to set your honing angle. I free hand that too. So I understand why you want a fairly accurate grind angle. You may do better freehanding the grind and using a ...I can't bring myself to write it....h h honing jig to help set your honing angle. (I did it).

   All i can tell you is, you can spend a lot of time on jigs and fixtures and approach all of your woodworking that way. Or you can just try a little harder and learn to do stuff by hand. It's really not that hard. It just takes a little care. And it's a skill that will serve you well.

   Adam

1. 
   Croc | Feb 10, 2009 03:45am | #10

   Great ideas!!

   Thanks to one and all

5. 
   badaash | May 10, 2012 12:04pm | #11

   Angle set-up gauge

   Hi Croc,

   You have probably solved this problem by now, but I couldn't help responding. Here's the answer to your problem of accurately setting up consistent angles on a wheel grinder:

   http://woodturning.org/tools/anglegauges/