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Thanks again JVH, you are helping me to get my head around all of this  . I relooked at the eccentric bushing idea and see now that it is a good way forward so I will resin-cast a 12mm tube against the inside of another larger tube (18mm) and then experiment with a scale to aid set-up.

I still cannot see how shims work unless they are used to rotate the blade in the jig, please see my attachment.

It is likely that the Tormek manual method has a small effect but for me, all it does is change how much I lift the handle of the blade. I will stick with the guideline approach (laser or otherwise) as this suits me and gets excellent results

Thanks again for your help

Hello Merx27,

a shim can help, but must be placed at the end of the jaw only (or have a triangle profile). An eccentric bushing is also very helpful here because the correction with shim is very rough and the bushing allows fine adjustment.

Other way is special jig. Although it looks weird, the blade is well centered. There is different angle on each side but also different protrusion length, so you get an even grind when you flip it.

See the photos for a better idea...

jvh

Hi JVH
I found shims very fiddley and sensitive to tiny movements, especially when the blade also tapered towards the tip. I could make them work but it took so much time to set it up. Have you a source for tapered shims, that would make like very much easier? Instead, I considering making different angle rebates in a couple of my SVM-45s but without a machine shop, this was likely to be a little uneven. I thought about using a homemade jig to hold the bottom jaw against my belt sander...

I like the look of the adjustable jig - did you make that? My fear, when considering something similar, was that the pivot between the shaft and the jaws might not be strong enough with a large knife but you have inspired me to reconsider. I'm not sure how the different protrusion lengths help but it may be that I haven't got my head fully around how you use it.

Thanks for sharing your experience, you are way ahead of me. I have received my casting resin and will get onto the eccentric bushing as soon as I finish the 5 Global knives and a food processor blade that came in today.

[one side of the jig is raised and the other is lowered. The axis of the top of the jig moves and this centers the blade.]

Hi JVH,
This is just the shot of my front page of the spreadsheet inspired by yours. To calculate the different USB height needed for the inverted jig: I use an angle finder to get 'Total angle between primary bevels' and then take that angle off the 'delta k' for the and then recalculate to give me desired bevel angle with new USB height. I then divide the difference in USB heights by 0.3 to give me the number of numerals to raise.

The eccentric cam can be similarly calculated but it is still prone to human error so I am currently focusing on a jig that holds Vee section blades in alignment as this removes the need to remember to do anything between sides but not yet settled on a solution. I do not see how the shimming methods can work as they still maintain the error in angle orientation and shifting the blade parallel to the jig makes no difference at all (IMHO)

Tonight, I experimented trying to get an even bevel width around the curve of a blade and when  I moved the jig towards or away from the tip of the blade, as suggested in the Tormek manual (P53 of v. 10.5) it made NO difference to the bevel width! So, I then used a laser guide-line across the stone while using the SVM45 and successfully kept an even bevel around the curve of the blade by keeping it on the laser line. This removed the black magic of how much to lift and rotate the blade.

Hello Merx27,

by turning the eccentric sleeve, one side of the jig is raised and the other is lowered. The axis of the top of the jig moves and this centers the blade. The aim is to obtain a symmetrical clamping before grinding and no further adjustment is required during grinding. The method I use is described below.

Shims method works the same way but from other side. Keep in mind that the work axis does not have to pass through the tool axis all the way, as this is not necessary - for correct adjustment the axis must pass through the axis of the blade and through the jig center in the point where it rests on the support.

I can confirm that the method described in the Tormek manual (P53 version 10.5) has a visible effect, at least on knives from a length of approx. 15 cm.

jvh

Thanks again JVH, you are helping me to get my head around all of this  . I relooked at the eccentric bushing idea and see now that it is a good way forward so I will resin-cast a 12mm tube against the inside of another larger tube (18mm) and then experiment with a scale to aid set-up.

I still cannot see how shims work unless they are used to rotate the blade in the jig, please see my attachment.

It is likely that the Tormek manual method has a small effect but for me, all it does is change how much I lift the handle of the blade. I will stick with the guideline approach (laser or otherwise) as this suits me and gets excellent results

Thanks again for your help

I then divide the difference in USB heights by 0.3 to give me the number of numerals to raise.

Hi Merx27,
in my understanding 1 numeral equals 0.25mm, as there are six numbers on the nut and thread pitch is 1.5mm.
(but maybe I missed an important thought)
Mike

Doh! You are absolutely right and underlines the need for me to pursue methods that minimise human error. Thank you Mike.

Your spreadsheet is awesome and your Excel skills far exceed mine. I had been creating my own spreadsheet for US height and when I saw yours I could see where I had been going wrong in making the trigonometry too difficult for myself. I have now added a simple extra to calculate the micro-adjustments needed between sides when clamping 'V' section knives to avoid the asymmetry of bevel grinds with the standard jigs. This is not the ideal solution as I need to readjust each time I turn the jig and there is a danger of forgetting! I am still experimenting with the other solutions from this forum...

I look forward to seeing the non-public updated version

Hello Merx27,

thank you for your feedback.

I hope that I understand what you mean... can you add a photo/screenshot to your post?

Isn't it easier to make these corrections on the SVM jig by turning the adjustable stop? I did this until I started using eccentric bushings.
I made a mark on adjustable stop, found required No. of turns to correct angle on second side, wrote 0 on the first side of blade and eg. +3/4 on the second side of blade and then tried to be 100% concentrated to flip the jig to the correct side while grinding. 

jvh

Hi JVH,
This is just the shot of my front page of the spreadsheet inspired by yours. To calculate the different USB height needed for the inverted jig: I use an angle finder to get 'Total angle between primary bevels' and then take that angle off the 'delta k' for the and then recalculate to give me desired bevel angle with new USB height. I then divide the difference in USB heights by 0.3 to give me the number of numerals to raise.

The eccentric cam can be similarly calculated but it is still prone to human error so I am currently focusing on a jig that holds Vee section blades in alignment as this removes the need to remember to do anything between sides but not yet settled on a solution. I do not see how the shimming methods can work as they still maintain the error in angle orientation and shifting the blade parallel to the jig makes no difference at all (IMHO)

Tonight, I experimented trying to get an even bevel width around the curve of a blade and when  I moved the jig towards or away from the tip of the blade, as suggested in the Tormek manual (P53 of v. 10.5) it made NO difference to the bevel width! So, I then used a laser guide-line across the stone while using the SVM45 and successfully kept an even bevel around the curve of the blade by keeping it on the laser line. This removed the black magic of how much to lift and rotate the blade.

Your spreadsheet is awesome and your Excel skills far exceed mine. I had been creating my own spreadsheet for US height and when I saw yours I could see where I had been going wrong in making the trigonometry too difficult for myself. I have now added a simple extra to calculate the micro-adjustments needed between sides when clamping 'V' section knives to avoid the asymmetry of bevel grinds with the standard jigs. This is not the ideal solution as I need to readjust each time I turn the jig and there is a danger of forgetting! I am still experimenting with the other solutions from this forum...

I look forward to seeing the non-public updated version

I did something similar but used M12 200mm (partially threaded) bolts which turned out to be too long as they got in the way of measuring my USB height in the vertical base so I trimmed some off as I have never yet needed to extend the FVB away from the Tormek casing