What's your workflow for multiple chisels? New to Tormek.

[Jan]

Rolf, tanks for your measurements on the SE-77 jig. 

For an edge angle of 30° and your protrusion 35 mm I have got the following results:
When you go from the SG stone (246 mm) to the SJ stone (244 mm) without changing the height of the USB, then the edge angle will increase to 30.9°.

To keep the same edge angle (30°) also for the smaller SJ stone you would have to increase the distance between the stone and the USB by 0.12 mm.

Jan

[Hatchcanyon]

Jan,

my test setup was for 25° and measuring of angle and height change quick and dirty.

Thanks for your explanation! 

Rolf

[Jan]

For the edge angle of 25° and your protrusion 35 mm are the results very similar: 

When you go from the SG stone (246 mm) to the SJ stone (244 mm) without changing the height of the USB, then the edge angle will increase to 25.8°.

To keep the same edge angle (25°) also for the smaller SJ stone you would have to increase the distance between the stone and the USB by 0.13 mm.

Jan

[Jan]

Hello Jan,

the protrusions are 53 and 33 mm. Works well with long and short blades.

I take always the same distance pieces regardless of the decreasing diameter. Since I use only one stone, it doesn't matter if the angle gets slightly steeper by time. It's not all that much. The stone wears slowly. This year I replaced it the first time after 8 years of use.

Klaus

Since I have read Waterstone's remark that he uses the same spacer block for chisel edge angle replication regardless grindstone diameter, I have been wondering how this influences the desired edge angle of 25°.   

Below there is a graph showing that the edge angle is decreasing from 25° for a 250 mm grind stone diameter to 18.5° for a 180 mm grind stone diameter. I have assumed that for setting the USB a spacer block with a height of 23.3 mm was used for all grindstone diameters.

Jan

[Ken S]

Klaus,

Changing wheel diameter with wear is why I use the TTS-100. Your chisel holding devices are leagues ahead of my primitive marking tape lines for setting the Protrusion.

However, I think your device to set the Distance between the universal support and the grinding wheel could benefit from some modification. If you take a look at the kenjig, the Distance is set by placing the Universal support in the groove. The length of the groove determines the Distance. As this simple piece of plywood is not self correcting for diameter changes, lengthening the groove approximately one millimeter for each ten millimeters of wheel loss will keep the bevel angle consistent (within reason).

We can simply correct this in two ways:
1) "Assign" the jig to the grinding wheel. Lengthen the groove to match the wear of the grinding wheel. Eventually you will need to replace both. Your replacement material cost will be a 30mm x 150mm piece of cardboard or plywood.
2) Make a set of jigs, one for each ten mm of wear.

I favor the first choice.

A third choice is one of the more sophisticated forum designed jigs.

Ken

[Jan]

To compensate for changing wheel diameter with wear we have to increase the height of the spacer block. The attached graph shows the situation for a desired edge angle 25° and chisel protrusion 53 mm. 

Jan

[Waterstone]

Hi Ken, Hi Jan,

I really wasn't aware that the decreasing stone diameter does have so much influence on the blade angle. Thanks for enlightening me. Looks that I've been a little careless in this regard. And yes, some chisel blades actually have rather 26 degrees than the intended 30 degrees. Since this was a slow process I didn't realize it. So I will have to change my strategy and skip the distance pieces. But it will be easy enough to set up the US by using the WM-200 at the correct distance. If a few chisels have to be sharpened, the adjustment has to be done only once.

The main reason to build the jig was my trouble with the SE-76 concerning the squareness. While using my jig the squareness of the blade will be made sure by using the edge as a reference. Only narrow irons can't be set up this way. That was the reason to make an additional removable side fence. Both ways are working very reliably. I don't have any irons out of square in my shop any more.

Thanks to both of you!
Klaus

Klaus

[Ken S]

Klaus,

Your jig works fine for setting Protrusion. It just needs a bit more support setting the Distance.

By the way, I am used to making jigs for knives with longer Distances. If you use the same 150mm piece of plywood for chisels (with shorter Distances), you can saw off enough wood to begin again with several wheels. Just make sure you leave instructions for making a new jig with your grandson.

Jan,

An old factory joke is sending an apprentice to the tool room looking for a "putting on tool". Instead of "putting on" the Distance gage block as the wheel decreases, I think it is easier to make the  negative space of the groove more negative. 

Ken

[Jan]

Klaus, you are welcome! 
I am glad to read my script works well. One spacer block is not enough, but three suitable spacer blocks may be enough for the whole life span of the grindstone.

For your convenience I am attaching a graph for the edge angle 30° and your protrusion 53 mm.

Ken,
when preparing the script for the square edge jig I felt like an apprentice also, because this is more complicated than knife jig. Please be so kind and test if it works for the new SE-77 also. 

Jan

[Ken S]

Jan,

I will do that during my next sharpening session.

Ken