Movement of USB when locking

[Sir Amwell]

Apologies in advance for going over old ground but I think worth revisiting.
The introduction of the KS123 has highlighted the old topic of the slight movement of the USB when locking it in place with the nuts on the sleeve housing. Not talking backlash here. Neither am I referring to the need to push down on the USB above the micro adjust when locking to minimise movement. That movement is still there and it's no longer a suspicion as you can see the pointer move on the scale of the KS123 if you check after locking down.
Does this matter?
I think it does.
There are issues with accuracy and consistency with this.
Some will say not enough to affect things overly much but if I'm going to hone a knife at +1.5 degrees from the original grinding angle to remove a bur and then at exact to clean up, a discrepancy of +/- half a degree ( sometimes more) is going to matter. To me anyway.
So any thoughts on this?
Any work arounds?
As a slight aside. I think the movement caused by locking (as the end of the screw engages with the leg of the USB in the sleeve) is not so much up and down as side to side? Hence it's the projection distance being affected rather than the height of the USB. If that makes sense.
Right. That's my Sunday morning issue put out there. I'm back to the workshop to dream of a perfect world........

[Ken S]

Sir A,

The handbook, being written by Torgny Jansson, can be considered the primary source of the original Tormek philosophy. Admittedly, this statement is not air tight. Torgny passed away around fifteen years ago. During those fifteen years , numerous innovations have occurred both at Tormek and by some of the Tormek users.

Examining two of the benefits of the online classes:

1) They have made improvements beyond those in the handbook available to users. an example of this is
"600 grit",  acknowledging that the stone grader is capable of producing more grits than just 220 and 100.
This was not a secret. Bofore the online classes, Tormek had no efficient means of mass communication.

2) Careful study of the online classes allows cross benefitting. By this I mean applying something shown in one class to a tool used in another class. The example of this which stands out to me in this topic originated in the T2 class.

While demonstrating the T2, Johan talks about making one more pass on both bevels with very light pressure to remove most of the burr. Applying this to the T8/T4, I am wondering if removing most of the burr this way might eliminate the need for the plus 1 1/2° rise. That might considerable lessen the error from adjusting the support height.

The original Tormek technique recommended freehand honing, with which support bar shifting would not have been a problem. I believe that position is changing to favor the greater precision of jig controlled honing with the MB-102. Further tweaking of technique may be necessary to reach full precision. This may need to be joint efforts by both Tormek and the forum members. Sadly, we have lost some very innovative members like Jan and Wootz; however, new members will arise.

It is worth the effort to keep moving forward.

Ken

[RickKrung]

Can you measure the difference, say with a caliper or indicator?  Is it consistent? 

Does it happen with just the vertical USB or also with the horizontal and/or the horzizontal/MB-102 when used as an Frontal Vertical Base?  If so, is the movement in the same direction, that is, is the effect on the projection distance the same? 

I wonder if this movement when tightening the screws is caused by a ridge or burr (unevenness/not flat) on the end of the screws. 

I suspect these screws are produces with what is called "rolling" the threads.  That is, the die that forms the threads uses pressure to create the threads by rolling over the screw shaft.  (In the past, thread were "cut" by using threading dies.)  This rolling process pushes material off the end of the screw, leaving a bit of a divot or crater in the middle.  It is typically uneven, being higher on one side or another. 

This burr will often leave marks and/or burrs on the surface against which the screw tightens.  It is easy to remove and make the end of the screw flat and uniform by filing or grinding.  I do this sometimes when I want the end of the screw to be flat and not marr the tightened surface.  This is common when set screws are tightened on shafts, making it difficult to remove the shafts.  Set screws are actually produced with this "cupped" end as a means to make the grip better.  Set screws are also available with flat ends so that they no not marr the surfaces. 

[cbwx34]

Apologies in advance for going over old ground but I think worth revisiting.
The introduction of the KS123 has highlighted the old topic of the slight movement of the USB when locking it in place with the nuts on the sleeve housing. Not talking backlash here. Neither am I referring to the need to push down on the USB above the micro adjust when locking to minimise movement. That movement is still there and it's no longer a suspicion as you can see the pointer move on the scale of the KS123 if you check after locking down.
Does this matter?
I think it does.
There are issues with accuracy and consistency with this.
Some will say not enough to affect things overly much but if I'm going to hone a knife at +1.5 degrees from the original grinding angle to remove a bur and then at exact to clean up, a discrepancy of +/- half a degree ( sometimes more) is going to matter. To me anyway.
So any thoughts on this?
Any work arounds?
As a slight aside. I think the movement caused by locking (as the end of the screw engages with the leg of the USB in the sleeve) is not so much up and down as side to side? Hence it's the projection distance being affected rather than the height of the USB. If that makes sense.
Right. That's my Sunday morning issue put out there. I'm back to the workshop to dream of a perfect world........

I spent some time this a.m. trying to get the angle to change looking at the KS-123, based on USB movement, and could barely get the needle to move.  So, I'm not sure how you're seeing it move that much when locking it down?

So, I then measured to the wheel using a digital angle gauge (this should also account for any Projection Distance change), and could detect around a .25mm change... that equals around less than .2 deg.  I don't know how you're getting as much difference ("a discrepancy of +/- half a degree ( sometimes more)") that you're seeing. 

Setting that aside, the need to hone at "decimal point" accuracy simply is not needed.  If based on KnifeGrinder's work, his "study" went thru a couple of iterations of his software that gave different answers (sometimes several degrees).  And the original version wasn't designed to work across several setups (like from Tormek to a grinder with paper wheels) so, when compared to the updated version, the answers again would vary.  (The "updated" KG software also has errors.) Plus, wouldn't this work be subject to the same USB movement?  The reality is most of the honing was just done at a higher angle than sharpened at, sometimes a lot more than stated.

So, the short answer, without more input on this, put me in the "doesn't matter" category.  I don't think you can be that accurate, nor does it matter.

[Columbo]

Can you measure the difference, say with a caliper or indicator?  Is it consistent? 

Does it happen with just the vertical USB or also with the horizontal and/or the horzizontal/MB-102 when used as an Frontal Vertical Base?  If so, is the movement in the same direction, that is, is the effect on the projection distance the same? 

I wonder if this movement when tightening the screws is caused by a ridge or burr (unevenness/not flat) on the end of the screws. 

I suspect these screws are produces with what is called "rolling" the threads.  That is, the die that forms the threads uses pressure to create the threads by rolling over the screw shaft.  (In the past, thread were "cut" by using threading dies.)  This rolling process pushes material off the end of the screw, leaving a bit of a divot or crater in the middle.  It is typically uneven, being higher on one side or another. 

This burr will often leave marks and/or burrs on the surface against which the screw tightens.  It is easy to remove and make the end of the screw flat and uniform by filing or grinding.  I do this sometimes when I want the end of the screw to be flat and not marr the tightened surface.  This is common when set screws are tightened on shafts, making it difficult to remove the shafts.  Set screws are actually produced with this "cupped" end as a means to make the grip better.  Set screws are also available with flat ends so that they no not marr the surfaces. 

Wow, now that's some amazing input

[Ken S]

Nylon tipped locking screws are specialty items. They may be found primarily is industrial hardware stores and may be pricey. However, they do a specialized job. Here is a link:

https://accu-components.com/us/nylon-tip-set-screws/1500-SSN-M6-26-5

Ken

[RichColvin]

Brass tipped set screws are also an option.  McMaster-Carr offers a number of options:  https://www.mcmaster.com/products/set-screws/tip-type~soft/

[RickKrung]

McMaster-Carr carries them all:

Stainless Steel, Nylon Tipped Set Screws

Metric Stainless Steel, Flat Tipped Set Screws

Metric Plastic, Flat Tipped Set Screws

Brass Set Screws