Frontal vertical base - my alternative

[jvh]

Hello everyone,

there is my version of Frontal vertical base, see enclosed drawings for details.

My first version had one threaded rod but I found it unnecessary because usually is FVB located on the stops or on defined steps. Therefore I made small notches on the surface with pipe cutter and I can replicate defined lenght easily.

Some notices:
- Adjusting rings are located 24,5 mm from the FVB body and it is minimum distance to avoid contact FVB with the Tormek's body (untouched painting). This distance can vary little bit on other machines.
- You can use round bar with drilled hole and internal thread instead of seamless tube.
- A little problem is with counter-nut's M5 tightening - there is not much place for the spanner. Something like Bahco 1931M-5 comes handy.
- Washers M8, ISO 7093 give enough support between tube and FVB body, the design is rigid. No problem after 6 months using.
- The dimension 30,85 (and 30,15 mm) can vary little bit too but it is exact distance to have my piece of Tormek Horicontal Base XB-100 centered with FVB body.

Enjoy!

jvh

[jvh]

Photos...

[Jan]

JVH, great work! Perfectly documented. Thanks for posting it.

Jan

[Dutchman]

I want to recall the following comment

Wootz
Regarding the following statement, I can point out two reasons why there is a difference.
Quote from: wootz on November 04, 2019, 03:56:26 am
=> What Ton does not mention, but I've found out, is that grinding with the wheel rotation goes differently to grinding into the wheel

• The mounting of the USB is different in both cases. Either in the FVB or in the original position on the other side.
• You adjust the position of the USB relative to the bottom not to the center of the stone.
With this setting, the distance from the USB to the center of the stone should be the same in both cases to obtain the same grinding angle.
Your experiments however show that this is not correct and you have adjusted the "math" accordingly.
I recommend that you take a critical look at the position of the FVB, as the deviation must come from there.
...

Have you tested whether "grinding with the wheel rotation is different to grinding into the wheel"?
In both cases, the distance from the usb to the center of the stone must be the same.

[smurfs]

Hi Ton,

I'd be grateful if you would clarify which angle you are referring to here...

I want to recall the following comment

snip...
With this setting, the distance from the USB to the center of the stone should be the same in both cases to obtain the same grinding angle.
...

Have you tested whether "grinding with the wheel rotation is different to grinding into the wheel"?
In both cases, the distance from the usb to the center of the stone must be the same.

If it is the edge angle then surely the distance from the USB to the center of the stone is immaterial as the relative projection and support bar height distances in each mounting position will ensure the same edge angle is maintained in each case.

That said, I would expect the heel and chord angles to differ where the distance from the usb to the center of the stone are not the same at each mounting position, so is this what you are referring to?
Edit: Struck out as the heel and chord angles will differ only where blade thicknesses differ. Should have thought this through before posting!

Thanks, Andrew

[jvh]

Have you tested whether "grinding with the wheel rotation is different to grinding into the wheel"?
In both cases, the distance from the usb to the center of the stone must be the same.

There is no difference in the grinded angle if you use correct calculations and well measured constants for your Tormek machine.

[cbwx34]

Nice work on the FVB!   

Hi Ton,

I'd be grateful if you would clarify which angle you are referring to here...

I want to recall the following comment

snip...
With this setting, the distance from the USB to the center of the stone should be the same in both cases to obtain the same grinding angle.
...

Have you tested whether "grinding with the wheel rotation is different to grinding into the wheel"?
In both cases, the distance from the usb to the center of the stone must be the same.

If it is the edge angle then surely the distance from the USB to the center of the stone is immaterial as the relative projection and support bar height distances in each mounting position will ensure the same edge angle is maintained in each case.
...
Thanks, Andrew

All the measurements are based on measuring from the "USB to the center of the stone", (see 'S' or 'D' in the diagram from Dutchman's book)...



... based on this, wootz (knifegrinders), came up with the 2nd step (triangle)...



... so that he could measure the USB height by measuring from the machine's casing, or top of the FVB.  But, (as seen by 'H' in the 2nd photo), it's still based off the original measurement from the USB to the wheel center.  (jvh's diagram ties it all together nicely)...



... showing how 'S' is the same in either direction/setup.

[Jan]

CB, at closer look you will find out that the three pictures are different. 

The figure 1 from the original Dutchmen's booklet defines S to the centre of the jig shaft. This S is not measurable distance. Calculations based on this figure are biased (up to 0.7 degree in bevel angle). This flaw was corrected in the revised booklet 2018.

The figure from Knifegrinders is tied to the original approximate Dutchnan's approach and therefore gives biased results. (The line H does not pass through the USB centerline!)

Only the drawing by JVH is correct and can be used to derive exact formulas. 

Jan

[cbwx34]

CB, at closer look you will find out that the three pictures are different. 

The figure 1 from the original Dutchmen's booklet defines S to the centre of the jig shaft. This S is not measurable distance. Calculations based on this figure are biased (up to 0.7 in bevel angle). This flaw was corrected in the revised booklet 2018.

The figure from Knifegrinders is tied to the original approximate Dutchnan's approach and therefore gives biased results. (The line H does not pass through the USB centerline!)

Only the drawing by JVH is correct and can be used to derive exact formulas. 

Jan

I'm just using it to show that the formulas all come from the same basic measurement... USB to wheel center.   You are correct, the revision "corrected" this, but the original diagram showed a simpler setup.

[Jan]

Just out of curiosity have you tried to grind away from the edge with the USB in the vertical sleeves? If the USB and knife jig setting remains the same for both towards the edge and away from the edge sharpening, than the edge angle is the same for both sharpening directions. 

More here https://forum.tormek.com/index.php?topic=3081.msg16707#msg16707

Jan

[cbwx34]

Just out of curiosity have you tried to grind away from the edge with the USB in the vertical sleeves? If the USB and knife jig setting remains the same for both towards the edge and away from the edge sharpening, than the edge angle is the same for both sharpening directions. 

More here https://forum.tormek.com/index.php?topic=3081.msg16707#msg16707

Jan

If you're asking me, I have not (that I can remember anyway), however I'm sure it would... and a quick check with a Sharpie and a "knife blank" supports this.

[Jan]

CB, thanks for your prompt confirmation! 

Jan

[Dutchman]

...
The figure 1 from the original Dutchmen's booklet defines S to the centre of the jig shaft.
This S is not measurable distance.
This flaw was corrected in the revised booklet 2018.
...

That was NOT a flaw.
My intention was to get a simple set-up of the grinding angle.
A simple ruler is sufficient, as can be seen in the photo that my booklets accompany on the download site.
If you think it is necessary to work in the submillimeter range, which requires extra measuring equipment, then show that too, but don't use a term like "flaw" for the time being.

[Jan]

Ton, I apologize for using an inappropriate term. You know I am not a native English speaker. Sorry for that mistake, there was no intention in it. I have corrected it in my post.

I have intended to say that the simplifying assumptions (approximation) made in your booklet 2013 were replaced by an exact approach and formulas in your revised booklet 2018.

Jan

[Merx27]

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