Author Topic: Stands  (Read 1685 times)

Offline Peck

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Stands
« on: March 28, 2022, 04:17:55 pm »
Hello I am new to the forums so forgive me if this isn't allowed. I am looking for stand supports to mount in front of low speed grinders for finishing the blade after grinding. I want them to accept the Tormek US-430 support so I can move straight from the Tormek to them as I was following the build from knife grinders but am now unable to buy the stands. I have alot of money tied up in this system so I cant just abandon it. Also been searching for the pivot jigs for sale. Thank you for any help.   

Offline Ken S

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Re: Stands
« Reply #1 on: March 28, 2022, 05:29:20 pm »
Welcome to the forum, Peck. Good question.

I would start with the BGM-100 and researching Wootz' (Vadim's) earlier work. As I recall, he used at least one prototype before settling on the more polished stands. The BGM-100 doesn't care if it is working with a grinder or a buffer.

Your set up doesn't need to be fancy; it's a tool, not parlor furniture. Make it easy to change; your third design idea will probably work better than your first. Hopefully other members will share other thoughts.

Please keep us posted.

Ken

Offline cbwx34

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Re: Stands
« Reply #2 on: March 28, 2022, 06:21:35 pm »
Hello I am new to the forums so forgive me if this isn't allowed. I am looking for stand supports to mount in front of low speed grinders for finishing the blade after grinding. I want them to accept the Tormek US-430 support so I can move straight from the Tormek to them as I was following the build from knife grinders but am now unable to buy the stands. I have alot of money tied up in this system so I cant just abandon it. Also been searching for the pivot jigs for sale. Thank you for any help.

If you haven't seen it, KG has a page with some instructions on it... should be able to build your own?

http://knifegrinders.com.au/11Shop_PWsupport.htm

I believe forum member Rich Colvin is coming out with a pivot collar, Schleifjunkies is another source.  (I've been using just a regular "Shaft Collar", works well)...



« Last Edit: March 28, 2022, 06:25:00 pm by cbwx34 »
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Offline Peck

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Re: Stands
« Reply #3 on: March 29, 2022, 02:44:30 am »
I tried to order them from knife grinders but it was rejected . I will look for the measurements to build a set. I seen he had an app for the buffer and tormek that are now unavailable is there any other apps that would allow the measurements to be put in?

Offline cbwx34

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Re: Stands
« Reply #4 on: March 29, 2022, 03:34:32 am »
I tried to order them from knife grinders but it was rejected . I will look for the measurements to build a set. I seen he had an app for the buffer and tormek that are now unavailable is there any other apps that would allow the measurements to be put in?

Calcapp (link in my signature) is universal.  It will work with any setup.
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Offline Peck

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Re: Stands
« Reply #5 on: March 29, 2022, 04:13:32 am »
Thank you as that was exactly what I needed!

Offline RickKrung

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Re: Stands
« Reply #6 on: March 29, 2022, 04:33:24 pm »
There are a number of ways to set up for bench grinder/buffer uses, KG's being one of them and Tormek's BGM-100 another.  I tried several and found that I liked best one that incorporates the Frontal Vertical Base (FVB) and BGM-100.  The KG and BGM along provide only one direction of adjustment - vertical.  Adding the FVB added horizontal adjustment which I find far more useful, particularly if doing a number of different operations besides just deburring knives. 

I might help if you could post some photos of the setup you have that we might get a better idea of what you are dealing with. 

Rick

Paper wheel setup similar to KG's


Traditional BGM mount.  Too low for most uses.


Elevated BGM mount similar to KG's, only vertical adjustment


FVB added to the BGM provided both vertical and horizontal adjustments, almost identical to how it works on a Tormek.


Drill bit jig platform setup on the FVB/BGM on a bench grinder.


Drill bit jig platform side view


Using the FVB/BGM setup with the drill bit jig sliding platform for a very non-standard application, small garden nipper/scissor blade sharpening with multiple angles. 
« Last Edit: March 29, 2022, 05:37:56 pm by RickKrung »
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

Offline Sir Amwell

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Re: Stands
« Reply #7 on: March 31, 2022, 12:46:18 am »
As a slight diversion. However you decide to proceed with your stands a word of caution. Your stands must be perpendicular to the surface your grinder is mounted on. If not your constant horizontal measurement will vary as you raise or lower the support bar and whatever software you use to determine angle will be inaccurate. Another way to consider this: using Vadim’s set up method for your slow speed grinder relies on that horizontal measurement to be constant at base level ( recommended 125mm I believe). If your stand is not perpendicular then up at the support bar level it will be out of alignment. Taking an accurate horizontal measurement is EXTREMELY difficult at the top end. The problem being is that even following Vadim’s set up procedure with his stands ( which are truly square) fixing them to a work surface throws out the square by tightening the fixings. 300mm above this causes problems. Ie 0.5 mm discrepancy at base level is exaggerated 300mm above that. If anyone knows how to overcome this it would be truly helpful for everyone who has problems with set up for this system of burr removal. Sadly Vadim is no longer here to guide us through this.

Offline Sir Amwell

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Re: Stands
« Reply #8 on: March 31, 2022, 12:57:32 am »
A further qualification to the above. If you are wondering about accuracy, Vadim himself told me that his aim was to get to within a tenth of a mm of accuracy on the vertical and horizontal constant measurements to make the software work. It’s difficult to achieve in a non engineering workshop environment. Again, any help or suggestions to help with this would, I’m sure, be hugely appreciated by anyone trying to implement this system.

Offline cbwx34

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Re: Stands
« Reply #9 on: March 31, 2022, 02:04:37 am »
As a slight diversion. However you decide to proceed with your stands a word of caution. Your stands must be perpendicular to the surface your grinder is mounted on. If not your constant horizontal measurement will vary as you raise or lower the support bar and whatever software you use to determine angle will be inaccurate. Another way to consider this: using Vadim’s set up method for your slow speed grinder relies on that horizontal measurement to be constant at base level ( recommended 125mm I believe). If your stand is not perpendicular then up at the support bar level it will be out of alignment. Taking an accurate horizontal measurement is EXTREMELY difficult at the top end. The problem being is that even following Vadim’s set up procedure with his stands ( which are truly square) fixing them to a work surface throws out the square by tightening the fixings. 300mm above this causes problems. Ie 0.5 mm discrepancy at base level is exaggerated 300mm above that. If anyone knows how to overcome this it would be truly helpful for everyone who has problems with set up for this system of burr removal. Sadly Vadim is no longer here to guide us through this.

Calcapp (that I mentioned earlier), TormekCalc, or any calculator that provides the measurement from the USB directly to the wheel eliminates this issue, since it doesn't require the horizontal or vertical constants.

A further qualification to the above. If you are wondering about accuracy, Vadim himself told me that his aim was to get to within a tenth of a mm of accuracy on the vertical and horizontal constant measurements to make the software work. It’s difficult to achieve in a non engineering workshop environment. Again, any help or suggestions to help with this would, I’m sure, be hugely appreciated by anyone trying to implement this system.

Decimal point accuracy was a bit overrated. ;)
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Offline tgbto

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Re: Stands
« Reply #10 on: March 31, 2022, 08:16:37 am »
And as errors exhibit the unfortunate tendancy to add up, taking a measurement that depends on as few other measurements as possible is desirable : the wheel to top-of-USB measurement is based only on wheel diameter.


Offline BeSharp

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Re: Stands
« Reply #11 on: March 31, 2022, 06:10:51 pm »
Your stands must be perpendicular to the surface your grinder is mounted on. If not your constant horizontal measurement will vary as you raise or lower the support bar and whatever software you use to determine angle will be inaccurate. If anyone knows how to overcome this it would be truly helpful for everyone who has problems with set up for this system of burr removal.

I quickly discovered this when my first attempt at stands used shelf brackets as braces. Shelf brackets are defintely NOT at 90 degrees. I resolved this by using assembly braces (clamping squares) by Jevons Tool Company: http://www.jevonstoolco.com/

The 90 degree angle is accurate to .002" (.05 mm) at 6" (150mm) away from the 90 degree angle.

Being in Canada, I bought them from Lee Valley Tools. Woodcraft in the US also sells them.

Offline cbwx34

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Re: Stands
« Reply #12 on: April 01, 2022, 03:42:15 pm »
One of the FVB setups I played around with a few years back...



... definitely not perpendicular ;)  (but measuring to the wheel allows for such a setup).

The reason is because calculators that measure to the wheel only need the wheel diameter (actually the radius, but the diameter is easier to measure) to complete the triangle (purple in the picture), while calculators that you measure to the machine need the additional measurements (the "constants") to complete the (orange) triangle.

« Last Edit: April 01, 2022, 03:45:05 pm by cbwx34 »
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Offline Ken S

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Re: Stands
« Reply #13 on: April 01, 2022, 05:07:32 pm »
I have thought of modifying my dry grinder with the BGM-100 for several years. I have the parts, but really don't like the idea of using a dusty dry grinder. As part of this project, I also purchased the Tormek OWC-1, which works in combination with the Wolverine shaft. This combination allows both vertical and horizontal movement. It could be mounted on the same board as the buffer. Mount the Wolverine shaft on spacer boards to the desired height. If needed, shims could true up the accuracy.

Ken

Offline smurfs

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Re: Stands
« Reply #14 on: April 04, 2022, 12:50:42 am »
As a slight diversion. However you decide to proceed with your stands a word of caution. Your stands must be perpendicular to the surface your grinder is mounted on. If not your constant horizontal measurement will vary as you raise or lower the support bar and whatever software you use to determine angle will be inaccurate. Another way to consider this: using Vadim’s set up method for your slow speed grinder relies on that horizontal measurement to be constant at base level ( recommended 125mm I believe). If your stand is not perpendicular then up at the support bar level it will be out of alignment. Taking an accurate horizontal measurement is EXTREMELY difficult at the top end. The problem being is that even following Vadim’s set up procedure with his stands ( which are truly square) fixing them to a work surface throws out the square by tightening the fixings. 300mm above this causes problems. Ie 0.5 mm discrepancy at base level is exaggerated 300mm above that. If anyone knows how to overcome this it would be truly helpful for everyone who has problems with set up for this system of burr removal. Sadly Vadim is no longer here to guide us through this.

The inaccuracy in perpendicular alignment can be overcome mathematically using an alternative approach to computing the support bar height from a given height origin, for example machine cover, sleeve face, etc., by replacing the step that relies on the constant vertical and horizontal dimensions. Note the bar to wheel height calculation remains unchanged.

The method I have come up with is machine agnostic and can be applied to any mounting point configuration. It was developed to solve two problems, namely:

1. To overcome the perpendicular alignment problem you have described, and;
2. To determine/define the minimum and maximum support bar physical operating height constraints in each mounting position.

The second point is business logic specific and ensures the calculated support bar height result (bar to wheel, and/or bar to some other height origin) is constrained to the bar range of operation for a particular mounting point. This is implemented in a database backed Android app I developed for my business.

The method is reliant on the scalene triangle formed between the wheel axle, the support bar fully inserted, and the support bar fully extended, for each combination of mounting and support bar. I haven't got around to documenting the math so I'll simply describe how the measurements are recorded for the Tormek vertical mounting point. Suffice to say the approach to measuring is the same for horizontal and FVB mountings.

With the wheel removed, insert the support bar fully in the sleeve. Measure the center-to-center distance between the wheel axle and support bar horizontal, then the support bar center to machine cover. This is the first set of measurements. Now extend the bar fully. It doesn't matter how high you set the bar so long as it can be safety used at this height. Now repeat the measurements with the bar in this position. It is important that the same height origin is used for both sets of measurements, in this example the machine cover (incidentally the axle to bar measurements are also used in bar-to-wheel constraint calculations too).

As you will see the measurements form a triangle of three known sides from which all unknowns can be determined, viz axle center to bar center at highest point, axle center to bar center at lowest point, bar center at highest point to bar center at lowest point (length of vertical side is the delta of both measurements).

One important property of this triangle is the largest angle formed between the axle center, bar center (low) and bar center (high) is fixed. In other words once it is determined it remains constant no matter the calculated height of the bar. So the bar could be 5 degrees off vertical and it won’t affect either the bar height to origin nor blade projection measurements at any height. This neatly addresses the problem of point 1 above.

This has turned into a bit of a long winded explanation so I’ll stop rambling now. To those interested in the math I will endeavour to write up steps and formulae in the next month or so.

As for the Android app I had no intention of releasing it as I didn’t want to cannibalize Wootz’s app income stream given others were commercializing his research and efforts without recompense. Obviously things have changed with his passing so I will revisit this decision and possibly release it gratis via the app store in the near future.