Tradesman DC Grinder

[Leo Van Der Loo]

It is easy to get blueing heat when grinding tools, also as I said this would not happen on a Tormec or other low speed grinder.

Just look at the sparks that come out when grinding, these are white hot, at least I see those.

The temperatures that are reached at the grinding area where the wheel hits the steel are high, though I have never seen any figures for that, but it is the reason cooling is important, studies have looked at this to improve the cooling (yes this is for industrial uses, but could apply to grinding tool steel for wood workers/turners somewhat), it is where even the layer of air alongside the wheels the coolant is prevented from actually doing its job, high speed coolant and shaped jets where developed to increase the cooling, and the effects of water based or oil coolants on the material used, again in industrial use.

Yes maybe not applicable to just resharpening a turning tool, and no diamond is not the best for sharpening the HSS tools, but yes it is for carbide grinding.

But even cBN is over the top for our turning tool sharpening IMO as a needed grinding wheel, but it has some bragging rights I suppose, as do all the super steels that are needed or used the turn some wood in the weekend or our spare time

 

[Don C Davis]

CBN grinds cooler than the friable stone wheels so common on grinders, faster and with more precision--due to the wheel balance--and it is ridiculous to think anyone gets their tools as hot as those listed temps--just doesn't happen--take it from a knifemaker with a fair bit of experience in hardening metal and making it soft when needed---tools are generally tempered for uses like woodturning--meaning the steel is intentionally made softer thus more durable and less brittle--end of rant---but trust me we don't get our tools that hot sharpening them!

 

[Michael Nathal]

I don't see the tool glowing red but I see sparks coming off that are white hot. Seems to me it is conceivable that the mating surface of the tool and the CBN and/or diamond could get that hot, but limited to a few ten thousandths of an inch deep.

 

[Odie]

I don't see the tool glowing red but I see sparks coming off that are white hot. Seems to me it is conceivable that the mating surface of the tool and the CBN and/or diamond could get that hot, but limited to a few ten thousandths of an inch deep.

Yes, I believe it is possible.....particularly right at the very tip of the cutting edge, where it is the thinnest. Where the steel is still thick (at the heel of the bevel, for instance), the heat can transfer, but there is no place to go right at the very tip......and, of course.....the very tip is where the cutting action takes place while the tool is being used.

-----odie-----

 

[Bill Boehme]

I don't see the tool glowing red but I see sparks coming off that are white hot. Seems to me it is conceivable that the mating surface of the tool and the CBN and/or diamond could get that hot, but limited to a few ten thousandths of an inch deep.

I think that it is a valid assumption that the filings are hot enough to glow, but I think that if we look at it from a thermodynamics perspective, a certain amount of energy is dissipated to remove each particle of steel. Because these particles have almost infinitesimal mass (some particles so fine that they float in the air for a minute or longer), the thermal energy dissipated in each of these particles results in enough of a temperature rise to glow. Just as in using a fluid or air coolant most of the thermal energy is carried off in the swarf. The huge mass (by comparison) of the tool and abrasive wheel would have very little temperature increase due to the remaining thermal energy.

Or, in layman terminology, the tool and wheel don't get warm enough to amount to a hill of beans.

Reference:

"Energy and Temperature Analysis in Grinding", W.B. Rowe¹, M.N. Morgan¹, A. Batako¹ & T. Jin²

¹ School of Engineering, Liverpool John Moores University, UK
² S.I.MS. CranJield University, UK
​

"Hill of Beans", Wiktionary​

 

[Leo Van Der Loo]

It is at the contact area where the high temperatures are developed and where the diamond can combine with iron, it will then increase the wear of the diamond.
It is for just that reason that cooling fluids are used.

maybe the hill of beans would be a good cooler for it

 

[Bill Boehme]

Here is a real world sharpening scenario. Suppose that we have a ¼" thick scraper being sharpened on an 8" CBN wheel on a slow speed bench grinder. Each second the wheel makes 28 revolutions which is 700 inches, so the length of time that a ¼" segment of the wheel is in contact with the steel scraper is 0.000357 seconds ... that's 357 microseconds.

I haven't seen any bluing of the steel with a CBN wheel, but just FYI here are some temperatures for various thin film oxide layers:

• 400°F (200°C) light straw
• 500°F (260°C) brown
• 540°F (280°C) purple
• 590°F (310°C) dark blue

 

[Leo Van Der Loo]

Just to put an end of my posting as of my understanding of the heat that is generated, there are all kinds of studies that have been done and still being done on these temperatures and the effects of it on the materials, and ways to reduce or control them.

Like in these.

https://ac.els-cdn.com/S22128271163...t=1525832709_6e3db2792a1fd9f998378aa51e29a3f4

https://ac.els-cdn.com/S22128271150...t=1525831639_e1468146940f516f580d5ba7dfdb1073

A short part of some of these is here, as taken from it.

 

[John Fenn]

I purchased one with 80 grit and 180 grit cbn wheels and the belt sander attachment with reverse a couple months ago. I haven't had an opportunity to use it enough to give you a detailed review or opinions except so far I really like it. Customer service was great when I purchased it and I haven't had a need to contact them further. It runs very smooth.

The price is the biggest concern but having sharp tools is a high priority to me and this grinder gives me the incentive to always have sharp tools.

Please let me know if you have specific questions, I would be happy to try to answer them.

 

[Dennis Weiner]

I purchased one with 80 grit and 180 grit cbn wheels and the belt sander attachment with reverse a couple months ago. I haven't had an opportunity to use it enough to give you a detailed review or opinions except so far I really like it. Customer service was great when I purchased it and I haven't had a need to contact them further. It runs very smooth.

The price is the biggest concern but having sharp tools is a high priority to me and this grinder gives me the incentive to always have sharp tools.

Please let me know if you have specific questions, I would be happy to try to answer them.

Did you buy the Tormek attachment?

 

[John Fenn]

I did not. That is something that I am still working through with respect to jigs and ways to hold things. I currently have the wolverine and vari-grind jigs. I don't have any Tormek jigs. If you have some Tormek jigs, I would definitely consider the Tormek attachment.

The grinder came with a couple of platforms including the Veritas platform, I think that will be of some value but I haven't made the time to play with it much. I use the belt attachment to freehand some grinding including a lawnmower blade which I would not do with the cbn wheels. I think the belt attachment is going to come in handy for misc. grinding. I have not found a good source for 1"x 48" belts (really haven't needed to) It seems to be an odd size.

 

[Dennis Weiner]

I did not. That is something that I am still working through with respect to jigs and ways to hold things. I currently have the wolverine and vari-grind jigs. I don't have any Tormek jigs. If you have some Tormek jigs, I would definitely consider the Tormek attachment.

The grinder came with a couple of platforms including the Veritas platform, I think that will be of some value but I haven't made the time to play with it much. I use the belt attachment to freehand some grinding including a lawnmower blade which I would not do with the cbn wheels. I think the belt attachment is going to come in handy for misc. grinding. I have not found a good source for 1"x 48" belts (really haven't needed to) It seems to be an odd size.

A good source for custom sanding belts is Econoway http://www.econaway.com/ . I use their ceramic and zirconium belts for most of my woodturning tools. They are very reasonable. I customized a 3450 rpm grinder with a belt sander with a few jigs that reached the height of the belt sanders platen. I used aluminum extrusions and parts from openbuilds.com for the jigs. I jury rigged it to run at about 800sfpm.

 

[John Fenn]

Great information! Thanks, it looks like their prices are good as well as getting the size in need. Thanks Again

 

[Bill Boehme]

What is the bench grinder driving that looks like a motor?

 

[Zach LaPerriere]

I purchased one with 80 grit and 180 grit cbn wheels and the belt sander attachment with reverse a couple months ago. I haven't had an opportunity to use it enough to give you a detailed review or opinions except so far I really like it. Customer service was great when I purchased it and I haven't had a need to contact them further. It runs very smooth.

The price is the biggest concern but having sharp tools is a high priority to me and this grinder gives me the incentive to always have sharp tools.

Please let me know if you have specific questions, I would be happy to try to answer them.

Thank you John. I will take you up on that! Agreed, customer service is exceptional. I've spent at least an hour total with Jeff, the founder and owner of Tradesman. Small world, he's in Ottawa now but spent a summer as a machinist in the later 70s in my hometown here in Alaska.

A few questions for you:
1. Did you own a cheaper grinder before upgrading to the Tradesman, and have you noticed a difference in sharpening with the much higher quality bearings?
2. Do you like the variable speed? I have a theory based upon the Tormek and my experience with power wetstones that slower sharpening may give a sharper surface.
3. Did you buy the leather belt for honing?

For what it's worth...it sounds like Tradesman sells belts pretty cheap...5 bucks a piece, and they have the belt lap cut down for give less of a bump in the lap. That's one of my main complaints with the Sorby Pro-Edge is that seam in the belt is like sharpening while riding a miniature galloping pony...

Thanks in advance for your answers, even if you haven't used your machine enough to comment fully.

 

[Clifton C]

Dennis, openbuilds.com, what fun, I just spent an easy hour and a half exploring their site. Thanks for the link.
c

 

[John Fenn]

A few questions for you:
1. Did you own a cheaper grinder before upgrading to the Tradesman, and have you noticed a difference in sharpening with the much higher quality bearings?

I have one but am new to turning and didn't use if for sharpening turning tools. I really don't have a comparison. My sense is that a cheaper grinder would work fine.


2. Do you like the variable speed? I have a theory based upon the Tormek and my experience with power wetstones that slower sharpening may give a sharper surface.

I find that I don't use the variable speed as much as I thought. It's nice, I typically start very slow and then speed it up to approximately 50 -60% which is about where a 1750 rpm grinder would be. Surprisingly, I think I speed up to about 50% because of my patience level rather than any perceived difference in sharpness. If the sharpening process is easy and quick, I use it and have sharp tools. If it is anything less than that, I avoid regular sharpening and end up with perhaps starting with a slightly sharper tool but ending and using a much duller tool before resharpening. For me its all about the ease of sharpening so I use it often. Having it run a little faster fits that category. I know there are a lot of people that know a lot more about sharpening and temperatures than I do. I don't really pay much attention to it. Once I get a profile I like, I sharpen and resharpen for literally a few seconds and then move on to using the tool. I don't think I get anywhere near the temperatures that effect the tempering of the steel.

3. Did you buy the leather belt for honing?

I have not, but would consider it. I currently use a flat leather strop at times particularly with skews. Again if it convenient, I use it, if it is more complicated it doesn't work well for me.

Bottomline, its difficult to justify the cost. Fortunately, I was in a position that the price was not the defining issue. I lusted over it for a couple years. Finally, I found a great replacement lathe at a very good price so I justified getting the top of the line grinder and some tools. Other than the price, I don't think you will regret it. However, if price is a primary issue, then a much cheaper is probably a better route. My personality is such that if I bought something else, I would always second guess it and covet the Tradesman. I agonized over the purchase, finally made my decision and haven't looked back. It will probably be sold at a garage sale in my estate (hopefully decades from now) for $25 and someone at that time is going to post their great garage sale find.

 

[Dennis Weiner]

What is the bench grinder driving that looks like a motor?

The black 1725rpm motor is driving the grinder! As a result, The speed at the belt is reduced to around 800 SFPM. Very similar to sorbey proedge speed. I can remove the belt and use the grinder with a 40 grid ceramic @ 3450rpm (5000 SFPM). I reshaped the Sorby 7/8 bowl gouge to a bottom feeder in a few minutes. In this mode, metal just melts away very rapidly. Here is a side view of my home grown sharpening system. Like the wolverine, the slide adjusts in and out but unlike the wolverine I have an up and down adjustment. The platform is an extrusion with an aluminum top that fits over the Tormek bar. The second photo on the left illustrates the underside construction of a smaller platform. I use the freebie maroon hartville platform as well. At some point when I find the time, I will detail in the tips area how to use economical aluminum extrusions to construct woodturning aids.

 

[Dennis Weiner]

Dennis, openbuilds.com, what fun, I just spent an easy hour and a half exploring their site. Thanks for the link.
c

Yea, it’s crazy what everyone’s building. Linear motion is very hot. I assume you signed up for their forums. Their parts are cheap. The good thing about working with aluminum is that you can use all your woodworking power tools to cut it. No other investment needed.

 

[Bill Boehme]

I need to look at your source for extrusions. I was going to order some extrusions from McMaster-Carr for mounting a Wixey digital readout to my thickness planer, but the prices were pretty high.

 

[Dennis Weiner]

I need to look at your source for extrusions. I was going to order some extrusions from McMaster-Carr for mounting a Wixey digital readout to my thickness planer, but the prices were pretty high.

Openbuilds -> parts store. In my pictures above, I used Vslot linear rail(20mm x 60mm), triple L brackets, some corner brackets and screws were M5 and m5 tnuts. The grinder is supported by some 2080 brand samples.. they would be close to 20x20mm in size.

 

[Larry Copas]

Another belt grinder fan. 36 grit to 2,500 grit or anything in between in 10 seconds. $3 belts last a year. All bowl gouges, and skews see the belt grinder. Sitting right next to it is a old Baldor grinder with standard grind rocks for scrapers. I've used both CBN and the Tormeck but see no advantage, at least one that opens my wallet, over my belt grinder. Yes, they have a huge advantage over standard grind rocks.

My 2 X 48 Kalmazoo belt grinder which is dedicated to the lathe. Shop made Oneway clone jigs completes the setup. It is a little tricky grinding bowl gouges with really long wings.

 

[Dennis Weiner]

Another belt grinder fan. 36 grit to 2,500 grit or anything in between in 10 seconds. $3 belts last a year. All bowl gouges, and skews see the belt grinder. Sitting right next to it is a old Baldor grinder with standard grind rocks for scrapers. I've used both CBN and the Tormeck but see no advantage, at least one that opens my wallet, over my belt grinder. Yes, they have a huge advantage over standard grind rocks.

My 2 X 48 Kalmazoo belt grinder which is dedicated to the lathe. Shop made Oneway clone jigs completes the setup. It is a little tricky grinding bowl gouges with really long wings.

View attachment 25372

I also keep my 6inch craftsman for scrapers. The wheels are down to 5 inches which make a wonderfully hollow ground burr. The belt sander handles everything else except my replacement new Ellsworth signature bowl gouge. It never sharpened well for me on any belt or stone wheel. I can finish off with a 180 diamond stone but like other powdered metal gouges they seem to sharpen better on CBN. I was looking for a source for custom CBN or diamond belts which I have not found as of yet. That’s why I was considering the tradesman with their 2x36 and 180 grit CBN wheel configuration.

I had problems with sharpening long wings on bowl gouges because I couldn’t swing the gouge clearing the grinder motor. I solved it by raising the jig up so that the gouge was near the top of the platen and sharpen more towards the left of the 2” wide belt when swing left and visa versa. But none of my wings exceed an inch.

 

[Zach LaPerriere]

Another belt grinder fan. 36 grit to 2,500 grit or anything in between in 10 seconds. $3 belts last a year. All bowl gouges, and skews see the belt grinder. Sitting right next to it is a old Baldor grinder with standard grind rocks for scrapers. I've used both CBN and the Tormeck but see no advantage, at least one that opens my wallet, over my belt grinder. Yes, they have a huge advantage over standard grind rocks.

My 2 X 48 Kalmazoo belt grinder which is dedicated to the lathe. Shop made Oneway clone jigs completes the setup. It is a little tricky grinding bowl gouges with really long wings.

View attachment 25372

Larry, That is a great set-up. I like how you adapted from where you saw best.

Can I ask how you like sharpening at the higher grits, when you sharpen at 2,500, and what kind of an edge you get sharp-wise?

Thanks,
Zach

 

[Larry Copas]

I can't tell much difference between 600 grit and 2,500 grit. I'm sure its a finer edge but fine edges dull fast.

My usual method is to use 180 to 320 grit. I sharpen a lot while turning and take a quick swipe or three on a bowl gouge removing just a wisp of metal. When using finer belts I have to concentrate more and really look at the edge to insure I have it sharp. Not saying its the best way, just my way.