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Why Tradesman DC Brief history Questions and Answers
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In the beginning:
We needed a reversing variable speed motor for a new tool grinder.
Jeff , was going to redesign the venerable old CUTTERMASTER The world had changed since 1972 and it needed some help.  In 2010 the Cuttermaster Professional was born using a Bodine Motor and control.

We bought one of every motor we could find and arrived at DC being the only thing that would work because of its smooth quiet yet powerful variable speed characteristics.

The control: We designed our own board, but landed correctly on KB electronics KBw16 and KBws25

The Wheels:  This is a good story we landed a contract to sharpen 100000 plus tools for Boeing Canada.  in 2007 (this started the Tolgrinder design project,I bought 2 Darex M5 drill sharpeners and soon was wearing out super abrasive wheels, so we designed our own in 2008 we now have 50 or so wheels that have been designed to be better than the ancient designs that were available.

Question and answers;
Lets start with this comment from one of our customers:
If an experienced woodturner had a choice of a variable speed lathe or a one-speed lathe, what would he or she choose?
1. What does DC give me, precisely?
a DC motor develops 5 times the torque of an AC motor.  In order to be useful through a range of speeds the motor needed to be DC.
2. What does variable speed give me in a grinder, concrete examples?
Higher torque means more material removal at lower speeds preventing excessive heat
3. How, in examples, does the Tradesman’s level of variable speed affect safety?
From a safety perspective having a super quiet controlled spin means you can tell exactly when the tool is in contact with the wheel and how much pressure is involved, The Tradesman spins Tradesman wheels so accurately that the wheel contact is uniform through the full revolution.
4. Who’s behind this grinder? Who’s the inventor? Why did he make what he made the way he made it?
 Jeff  Invented the Tradesman Grinder using the same DC motor he developed for the Cuttermaster Professional Tool and Cutter grinder, while on a trip to Florida with his friend Marty Rogers who wanted a better grinder for sharpening his Farm mower blades
5. What’s Tradesman’s level of support, coming from the mouths of those who have experienced it?
If your Tradesman ever needs work Our support is the best in the business 
6. Whom can I call who has a Tradesman DC Grinder, to get so-called straight talk from someone who isn’t selling them?
We are always happy to provide names of Happy Tradesman Fans we have a bunch.
7.  Super Abrasive wheels the facts
      CBN and Diamond Super abrasive wheels that are plated bond, have a layer of .002 to .008 depending on the grit bonded to the grinding surface Meaning the wheel need to run true or it will be destroyed, the flip side of that is when they do run true, at variable speed the grinding process is unrivaled.
8. The grinder is DC does it plug into an ac outlet.
Inside every Tradesman is a 130 Volt DC motor specifically built for out machines, it has a rather expensive Pulsewidth modulated board that converts 120 -240 volts to DC output. The PWM board is much quieter and produces cleaner power than the more common SCR type boards.
Our unique electronics combined with a great deal of engineering care and careful bearing selection is what makes our Tradesman the quietest grinder on the planet and a joy to use.
One of our customers suggested we say this (so we will) 🙂
The Tradesman reeks of “quality” and concern for excellence” and giving the user NEEDED CHOICES in speed.
Tradesman Grinders are uniquely designed to mount Plated bond CBN wheels  Inside every Tradesman there is a motor that was cheery picked from a batch of motors specifically for shaft straightness.  A 130 Volt DC motor specifically built for our machines.
Inside the Tradesman, a Pulse Width Modulated board converts the AC to DC and filters the noise out of AC current producing clean DC power.
Plated bond wheels are produced to a very tight tolerance because the shape cannot be adjusted once they are mounted. Shaft error and speed control are essential for long wheel life and good finish performance.
Our unique electronics combined with a great deal of engineering care and workmanship makes our Tradesman the quietest most unique grinder on the planet and a joy to use.
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How to sharpen a knife to a very sharp edge
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How to create a very sharp edge

The best approach to grind the knife bevel:

Use progressively finer grit wheels working towards a small uniform burr that can be accurately removed with a strop
 or edge honing process using very little pressure leaving a very sharp edge.

It’s all about understanding the material being sharpened, the process being used, and the accuracy of that process.  

KG” A good sharpener knows how to apex and deburr the edge; an expert sharpener knows how to clean the apex of the weak wire edge not rounding it”

Grinding or machining most materials, a burr will develop at the edge.

The Burr should be suitable for honing: Grind the knife bevels progressing thru wheel grits to a fine positive burr.

Our take on burr characteristics regarding positive and negative burrs.

Based on knife grinders’ observations and testing: A very good starting point.

 

 

Knife Sharpening to a very sharp edge explained

Grind the knife bevel using progressively finer grit wheels working towards a small uniform burr that can be accurately removed with a strop or edge honing process leaving a very sharp edge. Its all about accuracy.

KG” A good sharpener knows how to apex and deburr the edge; an expert sharpener knows how to clean the apex of the weak wire edge not rounding it”

Grinding or machining most material, a burr will develop at the edge.

Produce the perfect burr and then honing to the perfect edge.

Controlling the size and shape of the burr is essential when sharpening a knife bevel.

Producing a burr suitable for honing:
Grind the knife bevels progressing thru wheel grits to a fine positive burr.

Based on knife grinders’ observations and testing: A very good starting point.

MALLEABLE POSITIVE BURR BRITTLE NEGATIVE BURR
A high foil-like burr on a thin root.

A burr created edge-trailing, with conventional aluminium oxide and silicon carbide abrasives, and natural stones, using excessive pressure or high grinding speed.

 A small stiff burr on a wide root.

A burr created edge-leading, with CBN/diamond abrasives, using minimal pressure and low grinding speed.

A positive burr is a light feathery burr commonly produced by an edge trailing grinding process (wheel direction turning away from the edge)

 

 

 

Deburring,   If the last stroke was a stroke to the right then the first Debur  stroke is a stroke to the right  (burr up orientation)
This begins correctly the deburring process by protecting the belt and first op weakening the burr root for a more productive second side stroke.
1. Determine bevel angle based on steel (reference 1)
2. Set bevel angle using appropriate grit (320, 600?)
3. Set edge using appropriate grit (KG uses 1000)
4. Determine if the burr is positive or negative based on KG chart – steel (reference 2)
5. Differential Honing step 1 (positive for most commercial knives) one at the exact edge angle*, it will hone away the bulk of the burr with a 3-6 micron honing substrate
6. Differential Honing step 2 (positive for most commercial knives ) and the second at a 0.4 – 2 degree higher angle depending on the steel (e.g. a 15 dps edge will be honed at 15.4 – 17 dps), it will hone away the burr root and has 1-micron honing substrate.
Reference 1 – Know your material so that you can choose the best angle – DPS means degrees per side.
  • “best performing edge angle is the lowest possible for given steel” (KG 2019)
  • “Quality higher-end knives: double-bevel 10 dps, single-bevel 15-16 dps; Mainstream knives: double-bevel 12 dps, single-bevel 20 dps; Wear-resistant premium knives: modern PM steels 13-15 dps, and traditional tool steels 15-20 dps, as explained in the chapter on high end knives (KG 2019)
  • “Our sharpening workshop default edge angle for commercial kitchens is 12 dps (KG 2019)
  • “Getting rid of the gnarly burr cheapo knives usually produce is so difficult that you can clean the edge apex only at the cost of rounding it (KG 2019)

Reference 2 – Know your material so that you can choose the best deburring method –

  • “Positive burrs are produced in tough ductile steels, while negative in hard and brittle. The positive burr base is deburred by honing at a higher than the edge angle, while negative can be deburred by honing at the edge angle (KG 2019)
  • “It is plainly impossible to deburr a blade with a malleable burr (formed on mainstream stainless knives) by honing it edge-trailing at the edge angle” (KG 2019)   ““Feather burr” and “Foil edge” are two more edge geometries that can be created in the finishing stage of removing the burr; these two are near synonymic and are a product of edge-trailing honing at the edge angle (KG 2019)
  • “an edge sharpened at 20 degrees will require more deburring efforts than the edge sharpened at 40 degrees (KG 2019)
  • “honing the positive burr at the edge angle shapes it into a wire edge that won’t last while honing the negative burr at an angle higher than the edge rounds the edge causing an avoidable loss of keenness (KG 2019)
  • ” proper deburring requires a minimum of 2 steps”
The Deburring process is a fairly Discreet process, you are removing material, in very small amounts, keep this in mind if you have a large tough burr don’t go at it with a smooth leather wheel.
 you will be there all day and never be successful, go back to your CBN wheels and work thru progressively finer grits until you get a small workable burr.
Examples below
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Tradesman Edge 12 Digital – Radius Rail – A Variable Speed Reversing Sharpening (Killer deburing)
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Nothing but net!

Jeff

 

Ground Round Leather radial  hone wheel exactly the same diameter as the grinding wheels
  Quick-release wheels     

Angle positioning  and repeatability within arc seconds (free software on or off line)

 

Reversing, Variable speed 15 to 400 RPM

Mounts Tormek Waterbath wheels, reversing with digital Micro Adjust Rail

Magnetic Digital linear Scales each arm Rail on wheel center,

The blade is down in front of the operator.

*Accommodates a greater range of knife widths (paring knives to large cleavers) than any other grinder

*The only grinder that directly measures the clearance between rail and wheel, which is the most accurate and consistent way of setting knife bevels and eliminates numerous variables

*The only grinder that guarantees that the rail is precisely parallel to the wheel spindle (uniquely adjustable in this dimension, confirmable by dual DROs)

*Micro-adjustable to guarantee that the rail stays at precisely the same elevation as the wheel spindle (to ensure true radial adjustment)

Simplify the math  ,     Here is       Spreadsheet for Rail location calculation

Thank you, Patrick   Good thinking!

 

5.45 to 1 Timed Belt reduction 92MM 1800 RPM 130V DC
Toycen (Stump Puller) Motor

Link to Spreadsheet

 

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Tradesman Edge Mitre Jig (Micro feed rest) and Tormek Mount Leave both in place
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Note: the existing Tormek rails have long legs this length is not really needed on the Edge

The edge has been designed to be fairly versatile

Regarding the Veritas miter rest,   This is a no brainer
It is marginally useful if you cant adjust the feed while leaving the tool clamped.
Toycen solution: we added a feed mechanism no need to unclamp the tool and lose your angle to take another pass.

Here you can see our standard Feed rest and Tormek bracket mounted at the same time
no need to unmount our feed rests to use the standard work rest

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Static Electricity
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With our smart platen, there is a 1/8 inch  layer of 30 durometer closed-cell foam.

This isolates the belt from the machine ground, using our 3M belts static electricity builds up.

This will discharge thru your fingers for a little wake-up jolt if your the ground.

 

Either you can spray some laundry static guard on the back of the belt

Or you can use Aluminum Tape which is a good replaceable wear surface.

 

works well

 

Jeff

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Tradesman EDGE work station Belt Over Wheel Twin Feed rest New : Rear Tormek Mount
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Jeff designed the Belt-Over-Wheel attachment originally for the 8″ Tradesman.  The main benefits being that you can change grits (from wheel to belts) without breaking setups, and also save the life of your CBN or diamond grinding wheel. We recently had a customer ask for this set up on the Tradesman Machinist.

Here the BOW attachment is shown on the Tradesman edge  10 inch wheel one end 8 inch other end

Notice the Tormek Bracket on the back of the machine leaving the two from workrests in place

We like this set-up for knife grinding and works great with the Tormek attachments on the belt or wheel.

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