Setting Grinding Angles in the Digital Age

[sweet_strings]

I'm really excited by the Tormek's new ability to sharpen on the side of the grinding wheel and get a flat grind on my plane blades and chisels. Considering that the side of the wheel is a flat reference surface, is there any way one can set the grinding angle accurately & easily with one of the new, small digital angle guides? Would something like this Fowler mini-Mag Plus Protractor, which can measure angles at 360 degrees (4 X 90), do the trick?

http://www.fowlerprecision.com/Products/Electronic-Protractors/Fowler-mini-Mag-PLUS-Protractor-54-422-500-0.html

Thanks for your considerate help.
sweet_strings

[Twisted Trees]

I use a similar device for setting my saw blades, it appears accurate when tested by the eye and set square method that I used previously, and I have been happy with the accuracy of resulting cuts. I can't say with any certainty if that precision is good enough for flattening plane / chisel backs but it probably is as good as any other method. 

Have to say as my eyes age these digital readout devices are becoming more and more useful

[Ken S]

Sweet Strings,

The digital protractors use a horizontal surface as a reference surface (the "0" plane). (As I think about it, a vertical surface might work, also.) If you held your Tormek such that the side of the grinding wheel was horizontal instead of vertical, the gritted flat side of your diamond wheel could be your reference "0" surface. You could place your digital protractor on the back of your plane blade or chisel, it would read out in your desired bevel angle. Then just set up your Tormek right side up again.

Admittedly, this method might seem a little clumsy. However, if you carefully measure the blade projection of the blade and the position of the support bar, you should be able to easily duplicate the set up. (This is essentially just a variation on the kenjig, but used for flat grinding of chisels and plane blades.)

Please read my next post on flat grinding.....

Ken

[Ken S]

Flat vs Hollow grinding:

I think the ability to grind on the flat side of the diamond grinding wheels has interesting potential. However, I have seen no real instruction from Tormek about this. In the 1970s, when the Tormek was invented, hollow grinding was quite fashionable. Most home and small shop grinders had six inch diameter (150mm) wheels. The hollow was pronounced and considered to make finish sharpening with bench stones less laborious.

After decades of Tormek explaining how the hollow created by a 250mm diameter was almost imperceptable, I was surprised to see Tormek offer flat grinding. I am keeping an open mind on this and await wisdom from Sweden.

Ken

[MikeK]

I use a Wixey angle gauge in my shop, and I can't think of any way to use it to set the angle with respect to the vertical side of a grinding wheel.  The angle gauge, as far as I know, is designed to work perpendicular to gravity and will not register any movement when rotated around the vertical axis.

Unless I'm missing something important in the original question, I think only a mechanical gauge or trig functions can be used to establish the angle between the side of the wheel and the plane iron or chisel. 

[RickKrung]

These "angle cubes" are settable to zero on whatever surface you want, at whatever angle that surface may be.  Once that surface has been set to zero, placing it on another surface that is at a different angle (or the same surface after tilting it in some fashion) gives a reading of what angle that new surface is relative to the surface at which it was set to zero. 

iGaging Angle Cube placed on the base board of my recently completed Viel sander.


That same AC set to zero, in place, without moving the AC. 


Similarly, and this is how I plan on using the AC with my Viel. 

Place the AC on the belt/platen.  It does not read zero.  Actually, this is the angle at which I constructed the Viel to be at, so that when a knife is in the jig, on the belt and USB, it is essentially horizontal. 


Set it to zero.  In this case, the reference surface is not horizontal, but slightly off-angle from horizontal.  That it is close to horizontal is actually immaterial as the unit can be set to zero when attached to a vertical surface against which it is placed (magnets or not). 


Set it on the knife blade or other object to be sharpened and read the angle.  Adust the USB height to set the knife/jig at the desired angle. 


That is all for this post, due to the limit of photos per post. 

Rick

[RickKrung]

...snip...
I can't say with any certainty if that precision is good enough for flattening plane / chisel backs but it probably is as good as any other method. 
...snip...

I do not understand this comment.  I am not getting how an angle gauge is relevant to flattening the back of planes and chisels. 

It seems to me, that flattening is a matter of placing the non-flat surface against a grinding surface and abrading it until it is uniform.  This assumes the grinding surface is suitable for this operation, being flat itself, or that may not even be important and the abrading action may "even out" the irregularities, leaving the target surface flat in the doing.  I don't want to get distracted with whether the grinding surface is flat.  For this discussion, let's just assume it is flat. 

So, given that the target object is being ground flat on the grinding surface, where does measuring an angle come in to play?  I don't do flattening of chisel and plane blades, so I may just not get part of the procedure. 

Rick

[RickKrung]

Here is how I would use the Angle Cube (AC) to set the angle of an object to be sharpened using the flat side of a Tormek diamond wheel.

Just for reference, here is the AC on my FVB, which has been set to zero.


Place the AC against the side of the wheel.  Notice that it is placed with the side of the AC against the wheel, not the bottom, although that would not matter.  Also, note that the side of the wheel is not perpendicular with the top surface of my FVB. 


Set the angle for the side of the wheel to zero.


Place the freshly zeroed AC against the blade/object to be sharpened and note the angle displayed.  It is hard to read, but the angle displayed is 14.75 (I think).  Adjust the USB/MultiBase as needed to achieve the desired angle.  Sharpen away. 


Maybe I missed something or misunderstood something and I'm answering something that wasn't asked.  I'm open to having that cleared up. 

Rick

[RickKrung]

As for the accuracy and repeatability, my iGaging AngleCube (AC) shows and accuracy of ±0.2º with a repeatability of ±0.1º. 


±0.2º is within the range of what I think we are generally working, at least if using one of the angle setting applets.  Maybe not even that close, but I think the AC is at or better than what we can set the angles to using available resources. 

That level of accuracy may not be suitable for some woodworking applications, such as precision miter joints in fancy small box making (something I am pursuing in my woodworking endeavors). But, I am confident that for most general woodworking, it is more than adequate. 

I have a couple of precision angle setting instruments as part of my metalworking tools.  I'll see if I can figure anything out.

Rick

[Ken S]

I believe we are starting to think like tool and die makers or machinists instead of woodworkers. While this hyper accuracy is impressive, it does not seem necessary to me.

I once saw Duncan Phyfe's tool box on display in Williamsburg. He should certainly be included among the greatest furniture builders who ever lived. I doubt his bevels were sharpened to anywhere near
plus or minus a fraction of a degree. I appreciate the repeatability possible with Tormek jigs. In my opinion repeatability is more important than the exact angle reading of the bevel.

Ken

[RickKrung]

I believe we are starting to think like tool and die makers or machinists instead of woodworkers. While this hyper accuracy is impressive, it does not seem necessary to me.

I once saw Duncan Phyfe's tool box on display in Williamsburg. He should certainly be included among the greatest furniture builders who ever lived. I doubt his bevels were sharpened to anywhere near
plus or minus a fraction of a degree. I appreciate the repeatability possible with Tormek jigs. In my opinion repeatability is more important than the exact angle reading of the bevel.

Ken

"tool and die makers or machinists instead of woodworkers" ...  That almost sounds like a slam, Ken    Please keep in mind that I am a machinist first, sharpener second and woodworker last (or maybe just most recent  )

I agree that such accuracy is not necessary in most woodworking.  I also agree that master craftsmen likely do not concern themselves with this kind of accuracy in their bevels.  I also agree that repeatability is more important, at whatever angle or setting is used in both woodworking and our sharpening activities.  I was simply trying to clear up any questions about the use and accuracy of the Angle Cube devices (at least the one I have) since there seemed to be some questions and misconceptions. 

I will continue, exploring the couple/three methods I have for checking the accuracy of my AC.  But, for the moment, I have to go help my daughter load up some of her chicken farming equipment. She and my granddaughter are moving to a small farm of their own.  Soon, I will have my house and my shop back.  I am dreading the absence of my granddaughter in my everyday life, but know it is for the best and that I will see her often and regularly. 

Rick

[sweet_strings]

Thanks to all of you for these excellent comments and advice. I wasn't suggesting that I would use the angle cube for checking progress when flattening the back of a blade. I'm primarily interested in using it in place of the WM-200 Angle Master, which can be tricky to use without good light and a clear view, for setting up the primary bevel angles on my plane blades and chisels in relation to the side of the stone.

Since I prefer grinding my primary bevels with a flat grind and am excited by the beautiful flat-ground facets that the new Tormek diamond wheels can produce, it would be great if one can zero out an angle cube on the side of the wheel (the flat reference surface), as Rick suggested, and then place the angle cube on the blade to be ground and adjust the Multi Base until the desired bevel angle (say 25 degrees) registers on the cube's digital display. To me, this would be the simplest, most efficient, and probably the most accurate procedure for setting angles when sharpening on the side of the wheel.

Sweet_strings

[Ken S]

Rick,
No slam intended against woodworkers. It's just the nature of the beast with wood. Wood moves seasonally. That's why we need things like breadboard edges and clearances with things like doors and drawers. Fastidious woodworkers often use engine cut rules like those by Starrett for maximum accuracy. Accurate tools, but not tool and die level.

sweet strings,
There are simpler workarounds with very good accuracy instead of the Anglemaster. I rarely use the anglemaster. For almost ten years, I have set up my chisels and plane blades using the TTS-100. The same technology which works so well for turning tools works just as well for chisels and plane blades.
Using the SE jig, there are two things to set: The Distance between the grinding wheel and the support bar, and the Projection of the blade from the edge of the jig. Standardize the Distance by using the closer hole of the TTS-100.

Using one of the slots of the TTS-100, place a blank piece of labelmaker tape. Use the anglemaster just this once (in very good light). Set the Distance. Adjust only the projection of the blade  with the anglemaster to fit the desired angle. Yes, this is clumsy, but you only do it once. When you are satisfied that the set up and grind are correct, place the blade into the slot while still in the jig. Mark where the edge is in the slot.

For future blades, just set the Distance using the TTS-100 hole. This is only done once; it is constant. Set the Projection using the marker line.

This method is quick and quite repeatable.

Ken

ps I'm still not convinced about flat grinding for chisels and plane blades.

pps I later combined this method with Dutchman's tables to create the kenjig.

[Twisted Trees]

Here is how I would use the Angle Cube (AC) to set the angle of an object to be sharpened using the flat side of a Tormek diamond wheel.

Just for reference, here is the AC on my FVB, which has been set to zero.


Place the AC against the side of the wheel.  Notice that it is placed with the side of the AC against the wheel, not the bottom, although that would not matter.  Also, note that the side of the wheel is not perpendicular with the top surface of my FVB. 


Set the angle for the side of the wheel to zero.


Place the freshly zeroed AC against the blade/object to be sharpened and note the angle displayed.  It is hard to read, but the angle displayed is 14.75 (I think).  Adjust the USB/MultiBase as needed to achieve the desired angle.  Sharpen away. 


Maybe I missed something or misunderstood something and I'm answering something that wasn't asked.  I'm open to having that cleared up. 

Rick

I didn't really explain it well, basically in flattening the backs on the side of the wheel you would need a precise engineers 90° to the guide, while setting a saw for wood cutting 89.7° carpentry tools work on different tolerances

[sweet_strings]

Ken, I appreciate your comments and advice about the TTS-100 jig. Thank you. I'm not that concerned with repeatability, as I like to use different angles for different blades. The digital angle cubes would certainly make finding those angles easier when sharpening on the side of the stone, if it can be done. I won't get into a debate about what is better, hollow grinding or flat grinding. In short, I've tried both and have found that flat grinding produces a more durable edge on my plane blades and chisels and requires fewer visits to the sharpening stone.

The reason I'm curious about using the digital angle cube with my Tormek, is that many woodworkers use them in traditional manual sharpening to help set up a wide variety of angles in a sharpening jig. They place the digital angle cube on a flat stone, zero it out, and then place it on the face of their plane blades and chisels, and raise the blade up or down to the desired angle, which will register clearly on the screen of the digital angle guide. I can't think of anything simpler or more accurate in terms of setup. No distances to measure, no crouching down to see a sliver of light underneath the edge of a blade. Modern woodworkers are finding more and more uses for these little marvels. In a recent issue of Fine Woodworking, someone even suggested using them in place of winding sticks!

I don't yet own a digital angle cube that can measure 360 degrees (4 X 90), so I thought I would ask members of the forum if they have tried it for setting angles against the side of the Tormek wheel. Rick seems to have had great success with this procedure for his turning tools. Rick, have you tried it with plane blades and chisels?