Motorized TT-50 Truing Tool

[justme]

@Elden - love it!  (got a good chuckle).

@Ken S - I would be apt to do more truing (likely Tormek would sell more grindstones as a result) of having a consistent means to ensure that the stone is true.  I already had one experience where I had to re-do a knife because I didn't realize that there was a minor slope across the stone.  This wasn't obvious until you looked at the resultant blade.  Granted, I'm doing all of this for myself (not professionally), but having things "just right" is nice.

I believe RichKrung is onto something with the small stepper motor.

[RickKrung]

I believe RichKrung is onto something with the small stepper motor.

Justme,

You can just refer to me as "Rick K".

Got the motor I intend to use, or at least try first. 


Have written down some key dimensions and have the computer out to start drafting and designing, but it is late, I just finished a seven hour drive, with my granddaughter, to be with
family for Christmas. So I won't get much done for a week.

Rick K

[Ken S]

Justme,

I seem to recall Jeff Farris posting that he routinely trued his grinding wheel (SG-250) every time before reshaping a turning tool. Jeff is an expert turner.

I used my Tormek for several years before I felt comfortable using the TT -50 truing tool. A big part of that time lag for me was fear of wearing out or damaging my precious grinding wheel. Things improved when I started thinking of my grinding wheel as a long lasting consumable, like brake shoes.

Like you, I had several instances when my wheel looked true, but was causing problems because it was out of true.

Becoming proficient with the truing tool is not difficult. For me, an ideal training method would be instructor led and include truing the wheel half a dozen times in the class. Once you do it several times in a short period of time, like in an afternoon, it becomes second nature. Doing it once every year or two doesn't let the knowledge set in.

The stepper motor, perhaps with a flecible shaft, is a clever idea. The Unimat had a flexible shaft accessory. The motor had several pulley setups allowing very sliw RPM.

Ken

[RickKrung]

I am still in that "afraid to use the truing tool" too much phase, partially due to not wanting to wear it down too fast, but for at least one other reason.  I am not yet comfortable with what the truing tool is truing to.  As a machinist, I am accustomed to truing my machine tools to fairly precise levels (mostly my mill but also sanders and saws). 

I have not made a study of it yet, but the primary standard I would use is placing a square (in my case, a precision machinist's square) on the side of the stone and looking at how square the top (grinding surface) is to the side.  I'd then compare that to how square the USB is, in it's locked and working position.  I've not yet looked closely at this, but it is possible that the USB is not square to the side of the stone, which is what this reference really is.  I've thought about this a little, thinking that the USB's position is determined by the holes in the housing, secured by the locking screw.  The vertical shaft of the USB being forced against inside diameter would determine its vertical alignment, which would project to the horizontal alignment of the USB, relative to the top surface of the stone.  While everything I've seen so far regarding precision and quality of construction of the Tormek is excellent, it does not automatically mean the USB mount holes are in alignment with the side of the stone and therefore perpendicular to the top of the stone. 

Trust but verify. 

I would hold my square on the side of the stone and look at the surface of the stone.  Shine a light behind it and look for any differences in light showing through.  And then lower the USB to the top surface of the square and tool at how square it is, in its locked position to the side of the square.  They are not necessarily the same (short version of the long winded above).

And then I wonder... What difference does it make... ?  I've read about how the stone not being true has caused problems.  I don't get it.  Knife sharpening and other free-hand sharpening, one is guiding the knife (or whatever) along the surface (however square or not), watching the level of water build up along the surface.  Square tool jig, if the stone has been trued to the USB, wouldn't it still produce a squared edge, regardless of how slightly un-square the USB and stone top surface might be to the side of the stone?

Just wondering,

Rick K

[RichColvin]

Rick,

I'm in your camp.  Except for plane blades & chisels, the alignment of the USB to the stone isn't terribly critical.  That is because most jigs moves freely along the USB.  (I don't sharpen planer blades.)

But, as I sharpen the tools like bowl gouges, I find there are ruts or other unevenness left on the stone surface.  Truing the stone gets it back to flat. 

And as for using up the stone, i have had my Tormek for 15 years, and have fully consumed one SG-250 grindstone, and half of an SB-250 grindstone.  The SJ stone I have is still 240-245 mm.  So, I figure getting 10 years or so from a stone isn't too bad.

Rich

[RickKrung]

Rick,

I'm in your camp.  Except for plane blades & chisels, the alignment of the USB to the stone isn't terribly critical.  That is because most jigs moves freely along the USB.  (I don't sharpen planer blades.)

But, as I sharpen the tools like bowl gouges, I find there are ruts or other unevenness left on the stone surface.  Truing the stone gets it back to flat. 

And as for using up the stone, i have had my Tormek for 15 years, and have fully consumed one SG-250 grindstone, and half of an SB-250 grindstone.  The SJ stone I have is still 240-245 mm.  So, I figure getting 10 years or so from a stone isn't too bad.

Rich

Rich,

I'm still trying to figure this out: "Except for plane blades & chisels".  If the stone grinding surface is true to the USB, why would it matter if these are not true to the side of the stone (rest of the world)?  I see it the same as leveling a lathe, where leveling puts the ways square and parallel to the spindle axis (and it then cuts a true cylinder), regardless of how these relate to the rest of the world, ie, levelness to the surface on which the lathe rests. 

I get it about the need to return a stone to being flat, after causing it become not so. 

I'll take your comments on stone use on faith.  I'm too novice yet to have sense of how long it takes to wear out a stone.  I've unfortunately had too much else going on to use the Tormek as much as I'd like and have only had it for a few months. 

Rick

[Ken S]

Rick,

With my longtime consuming hobby interest in machine shop technology, I think I partially understand your machinist thinking. Let me take you backstage with my thinking.

A decision from over forty years ago illustrates my thinking. I was purchasing an enlarger for my photographic darkroom. I debated whether or not to spend fifty dollars more to get stabilized voltage. I did not think I had a voltage fluctuation problem, however, having stabilized voltage would eliminate any potential voltage problems. I spent the extra fifty bucks for peace of mind.

That thought process is still with me. While not all tools may require a true grinding wheel, having the grinding routinely trued will effectively eliminate problems associated with the wheel being out of true. Things like routinely and skillfully truing the grinding wheel, becoming fluent with the stone grader; and keeping the water trough clean all help reduce the number of potential problems.

Call me overcautious; that's how I think.

Ken

[RickKrung]

I'd say we think and behave similarly.  I usually buy higher end tools and equipment when I can afford them, and sometimes when I can't really afford them.  Bit of curse, but I don't try very hard to break it. 

Rick

[RichColvin]

Rick,

What I'm saying about chisels & plane blades is this :  they are held by a jig like the SE-76 or -77.  This jig rides on the USB and moves only laterally.  So, if the USB is not exactly parallel to the wheel's surface, the chisel or plane blade will be sharpened so that the edge is not exactly 90 degrees to the blade's side.

This can happen easily due to two things :

• the grindstone truing happens from the vertical position, and I sharpen those blades from the horizontal position. This change will certainly introduce some level of error, though it will be small.
• even when using the same position, just moving the USB in or out will introduce some error as the machine does not ensure perfect alignment of the USB arms, and this will also certainly introduce some level of error, though it will also be small.  (Ensuring perfect alignment would require a significant enhancement to the machine's cost!)

In the world of machining, this is a big deal.  But, I don't know how much this will matter unless you're a far better woodworking expert than I.

Kind regards,
Rich

[RickKrung]

Rich,

I do get what you are saying about chisels and plane blades not turning out square if there is a lateral slope/angle of the stone surface and the USB is square (or close to it) with the side of the stone.  I was trying to make the case that if the USB was sloped the same as the grinding surface of the stone, they would turn out square.  This is based on an assumption that if the stone were trued using the USB and the tool grinding are both done from the vertical position. You said you do your grinding from the horizontal, so I do get that it would make a difference there.  So, why not do the truing from the same horizontal position at which you do your grinding.

This whole discussion just gave me a brilliant idea (we'll see about that).   My implied assumption above is that the USB is positioned consistently because the screw forces the USB against the back of the hole. As Rich points out, that is not as consistent as it needs to be for his purposes.  So, what if the holes in the case where the USB mounts were the same as the "paatented" holes in the jigs that mounts the jigs so securely on the USB?  That out-of-round shape would be powerful at forcing the USB to lock down in exactly the same alignment every time.  Think about it.

Rick

[Ken S]

Rick,

It's early morning and I don't want to risk waking my wife on one of the few mornings when she has the chance to sleep later. So, I will answer your reply without the benefit of looking at my TT-50. I don't know if your idea of using the patented Torlock would work or not, however, I would give it an award for clever thinking. I have a high regard for the clever thinking of good machinists. Keep up the good work!

I don't know how much tolerance sharpening needs for different operations. I have never seen a blueprint specifying either a tolerance range of a minimum surface smoothness. I suspect they don't exist. Considering how often planes are used skew; both planes and chisels are intentionally ground skew; and that almost all bench planes made for over a century have lateral adjustment, I suspect that being "dead square" is not a high priority.

A game changer for me was reading the book, Gaging and Inspection. This book goes back to the need to quickly train thousands of skilled factory workers during World War II. It made me aware of controlling the variables I could in order to lessen the impact of those I could not control. Your use of your precision square is an example of this. Checking with a precision square takes no more time than using just a relatively square tool. Your ground edges are consistently more square for the choice.

I look at using the truing tool as a two axis graph. The horizontal X axis is time in use. The vertical Y axis is truenessof the grinding wheel. As we use the wheel it gradually becomes untrue. Tormek tells us that this amount of untrueness accelerates as the wheel becomes increasingly out of true. Our graph line is a descending slope. It can be a continuous line if we do not true the wheel. Or, the line can resemble saw teeth with regular light truing. Tormek tells us a wheel infrequently trued will wear faster than a regularly trued wheel. I have not verified this. However, if we convert the lines to average trueness, the average for the regularly trued line which never dips below a certain point will be substantially higher than the occasionally or never trued line average.

That is a controllable gremlin. Other gremlins are not so easily controllable.

I think the same principle applies to sharpening. Hand cutting dovetails, I can feel when the chisel becomes dull. It still cuts, but with more effort. Why keep cutting if a quick trip to the Tormek will restore optimum performance?

I am all for practices or improvements in our tools which tighten tolerances in a practical manner.

Ken

[RickKrung]

Ken,

I found two versions of the book, one dated 1951 and another 1987.  The first had a single author, the latter three.

I've been working on CAD drawings for the motorization of the Truing Tool (attached). The PDF file has the entire assembly at the beginning and end.  In between is each piece sequenced as it might be assembled.  I'm at relatives for Christmas and didn't bring anything but the motor so my representation of the Truing Tool is very generalized.  I'll get specific with it after I return home.  After that I'll add dimensions on the individual piece drawings and then work can begin. 

Pretty simple construction.  I believe it could be done with a drill, a tap and a hacksaw.  Drill press would be very handy as would a belt or disk sander to clean up the sawn edges.  Material should be aluminum.  I will use extruded box aluminum because it has square/sharp corners rather than the curved inner corner of angle stock. I have several different sizes of the box alum. and if I'm lucky, I can simplify this design by cutting off just one side to yield a three sided bracket and making the shaft mount of the knob chuck longer or shorter to suit. 

Rick

[Ken S]

Rick.

I look forward to learning more about your project.

Enjoy the holidays with your family; that is special time.

Ken

[RickKrung]

Here is a revised version, based on use of the box angle aluminum for the motor mount.  Only two parts to fabricate, the motor mount and the knob chuck.  I am pretty sure I have 2" wide box extrusion.  Also, I forgot that the knob chuck requires a metal lathe, so construction isn't quite as easy as I thought.  It would be possible to secure the motor shaft to the knob using parts that don't require a lathe. 

I'm leaving the earlier version posted for those who don't have access to the box alum. 

Rick

[justme]

@Rick K - noted on name.  Wow!  Was not expecting that you'd be working on CAD drawings.  (I'm excited!). If there's something that I can lend to this/help - please let me know.  (Not sure what I can provide, but interested in helping if possible).

@Ken S - Despite the cost of the stones, I see those as purely consumable and one shouldn't be overly concerned with it's depletion.  If truing happens to remove more than the sharpening, but ensures consistent angle - I'm fine with replacement.  Granted, don't want it to be yearly, unless I'm doing enough sharpening to account for it.  . I don't have any inhibition about truing it repeatedly and regularly.  I think the first few times is more about getting used to/comfortable with some of the odd noises and vibrations that come with it's use.  Those were [arguably] the most disconcerting the first few rounds with each type of stone.

I'm in the same camp (as well) as Rick K and Ken S in terms of things - overbuilt/peace of mind to ensure that things are optimal.