Setting grinder angles??

Re: Setting grinder angles??

John McGaw

I've given up on trying to get precise angles on a regular grinder and now only use mine for rough and ready jobs. For precision angles I find that a blue zirconium belt on a cheap 1" benchtop sander does the job quickly and accurately. If I'm looking for a high polish (and I'm not too lazy at the moment) I'll break out the ancient Makita wet sharpener and dress the edge left by the sander. If a fine grit belt is used the finish usually doesn't really need so much polishing that it can't be done by hand.

The only things beyond gardening tools I sharpen on the grinder are the edges on roughing gouges and the like and for those I either freehand the angle or set the rest according to whatever angle the tool already has.

yes and no

John K Jordan

Many angle setting jigs have been devised to do just that for woodturning tools. Glenn Lucas and Rudy Lopes have had them on their web site in the past and I've seen them in several books, e.g., Darlow's "Fundamentals of Woodturning." All of them work very well to repeat a grind angle. You can devise a calibrated stand or buy something like a Robo rest.

However, the problem with all of these is since the grinding wheel is curved instead of flat the exact angle is dependent on the thickness of the tool and how the angle is measured - across the bevel, just at the tip?

What are you sharpening? If sharpening turning tools, you might ask this in the turning section and the other forum you frequent.

JKJ

what is the need?

Bill Tindall, E.Tn.

If you are grinding plane blades and chisels and want to replicate whatever angle is on the tool the approach is easy. Put the too on the rest and spin the wheel by hand with tool lightly touching. If the wheel does not hit in the middle of the bevel tap the rest until it does.

Re: what is the need?

Tom Norton

I probably should have said I was thinking of it for grinding a new angle on some tools I beautiful to try making.

So I need a reference point.

Re: Setting grinder angles??

Dick Coers

I just use a protractor to put a line on the side of the steel. Eyeball it against the OD of the wheel and start grinding. Before you get to the final grind, check with a protractor again. Then move the platform and grind to the final edge. Works great!

Easy peazy

Derek Cohen (in Perth, Australia)

I wrote the follow for an article on my website in 2008 (my gear has changed since then). This method is to create a fresh angle. If you are happy with the one you have, use the method mentioned by Bill (where you scratch the centre of the hollow). On my current set up (8" CBN wheels and no guards on the grinder), I use a Tormek angle setter. Or scratch the hollow.

"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 significantly smaller, it will be necessary to make a fresh jig (I emphasise “significantly” smaller since a little bit here-or-there is not important in the grand scheme of things). The only jig I am aware of that adjusts for different diameter wheels is the Angle Setter jig for 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 ...

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. To test this, use a felt tip marker (texta, magic marker) and colour the bevel. Place the blade on the rest and – with the power off – move the wheel back-and-forth to create a slight scratch pattern. Adjust the rest until the scratch is in the centre of the thickness of the bevel.

Retract the blade on the rest until it no longer touches the wheel (you may want to clamp it here so that it does not move).

Place a block of wood on top of the blade and hollow grind that. This will give you a template to reproduce that angle.

Do another for 30 degrees (and any others you wish)."

Regards from Perth (currently in Cape Town)

Derek

Re: Easy peazy

Tom Norton

Thanks! That is what I am looking for!!!

what I use is this

Don Evans

Take a look at this, it is what I use. It's magnetic and sets on the rest while making adjustments works good for my use YMMV

http://www.sears.com/craftsman-magnetic-universal-protractor/p-00939840000P?plpSellerId=Sears&prdNo=7&blockNo=7&blockType=G7

I don't recommend Sears to anyone because of the bad experiences I've had with them. I purchased mine years ago about 30 years ago.

But I knew I could locate this link quickly.

Don