Jet Variable Speed Bench Grinder Opinions?

[Treeman]

I'm torn between the Jet 3600 RPM Industrial Bench Grinder and it's variable speed equivalent for an Ag. Equipment shop.
https://jettools.com/ibg-8-8-industrial-bench-grinder ..... vs. ... https://jettools.com/ibg-8vs-8in-variable-speed-industrial-grinder

Will the more complex variable speed electronics fail? The touch pad concerns me, knowing how messy heavy metal grinding can get.
1750 rpm vs. 3500rpm (my experience limited to grinder below).

Opinions/comments much appreciated. Thank you.

FYI, my 60+ year old 10 inch, 100 lb. tank-like SkilSaw 3 phase 220 v, 1750 rpm grinder died (rebuild not an option). Baldor is out of my price range. Used probably not an option (work place).

 

[Steve_P]

I have the first Jet in your links. It's a beast, I love it. I'm a huge fan of variable speed in many tools, hand-held belt sander, angle grinder, but I never felt the need for it in a bench grinder- then it's time for max material removal.

Project Farm did a bench grinder test, but the TLDW summary is amps are king, which we all should know, and the first Jet has it.

 

[dnschmidt]

No reason to get a low speed grinder unless you're sharpening chisels which could be affected by the additional heat. Door #1 is what I would pick. If you want to sharpen something get a Tormek.

 

[seber]

I use a dedicated low speed grinder for sharpening with a very soft wheel. So it is useful. But for grinding and buffing, not so much. That said, I wouldn't worry about the electronics as I'm sure they are well protected in a sealed environment. The only thing that is going to cause problems is heat. If you intend to run this thing hard for extended periods, VS may not be a good choice.

 

[Treeman]

Thank you all for the input. In the past I have never used a power tool to sharpen knives, chisels, etc.. I have bench grinded mower blades carefully, using a water dip to keep them cool. And, I do enjoy a wire wheel on my bench grinder to clean up things.

I'm leaning towards the single speed. My old 10 inch was 1750 RPM. Will an 8 inch wheel at 3400 rpm cause any issues?

 

[Hohn]

I'm leaning towards the single speed. My old 10 inch was 1750 RPM. Will an 8 inch wheel at 3400 rpm cause any issues?

Issues for the tool, the grinder, or the wheel?

The wheels clearly indicate the max rated RPM, so that's easily resolved. And obviously the grinder itself is spinning at a speed the maker desired.

So that leaves the tools you are sharpening.

Best advice I can give anyone is that grinding speed and precision are mutually exclusive. If you need precision, you can't have speed. And if you need speed, you can't have precision.

So, if you are sharpening a shovel, a bench grinder is a good use for that. But it's a terrible choice anywhere you need a keen edge unless you get a specialty set specifically designed for the purpose (i.e. the paper discs and such).

 

[Hohn]

I have the first Jet in your links. It's a beast, I love it. I'm a huge fan of variable speed in many tools, hand-held belt sander, angle grinder, but I never felt the need for it in a bench grinder- then it's time for max material removal.

Project Farm did a bench grinder test, but the TLDW summary is amps are king, which we all should know, and the first Jet has it.

Amps are king because all bench grinders are the same basic design and the height of simplicity. The larger the motor, the more torque it will have at its rated RPM, and thus the more material it can remove per unit time.

 

[Hohn]

I'm torn between the Jet 3600 RPM Industrial Bench Grinder and it's variable speed equivalent for an Ag. Equipment shop.
https://jettools.com/ibg-8-8-industrial-bench-grinder ..... vs. ... https://jettools.com/ibg-8vs-8in-variable-speed-industrial-grinder

Will the more complex variable speed electronics fail? The touch pad concerns me, knowing how messy heavy metal grinding can get.
1750 rpm vs. 3500rpm (my experience limited to grinder below).

Opinions/comments much appreciated. Thank you.

FYI, my 60+ year old 10 inch, 100 lb. tank-like SkilSaw 3 phase 220 v, 1750 rpm grinder died (rebuild not an option). Baldor is out of my price range. Used probably not an option (work place).

I think your instincts are wise here, the touch pads are a common failure point on most home appliances. But touch pads are also used on every CNC machine tool, gas station pumps that have to endure a terrible life, etc.

So I don't think the touch pad is unreliable per se. But why take the risk when a basic toggle switch is bombproof and easily replaced?
Personally in your situation, I would go with a reasonably quality (Dayton?) fixed speed, toggle-switch 8" with a MultiTool belt grinder attachment. I can't think of anything that a fixed grinder wheel does better than the multitool attachment or any large belt grinder.

Especially in a shop environment, the ability to quickly change belts it a HUGE value add-- whether it's worn, you need a different grit, or you need a different kind of abrasive for a different material.

Baldor is IMO overpriced for what they are. I think any bench grinder in the 8amp range with a multitool will hold up quite nicely, add a lot of productivity, and not break the bank.
Remember, cost is only one side of the equation-- the other half is just as important. What are you getting for that cost? I think the belt grinder option really adds value.

 

[dnschmidt]

I've mentioned this before in another post but the one thing a grinder is superior to a belt grinder for is sharpening drill or lathe bits. The curvature of the wheel provides the necessary back relief that's very hard to achieve with a belt grinder. There are many things a belt grinder is superior at: sharpening TIG tungsten being one of them, but for drill bits and lathe bits the grinder is far better.

 

[GeoBruin]

I'm leaning towards the single speed. My old 10 inch was 1750 RPM. Will an 8 inch wheel at 3400 rpm cause any issues?

In terms of surface feet per minute, your 10" was giving you just over 4,500 sfm, while the 8" will give you over 7,000 sfm. You should notice an increase in material removal rate, but also likely an increase in heat generated.

 

[Beerhippie]

Issues for the tool, the grinder, or the wheel?

The wheels clearly indicate the max rated RPM, so that's easily resolved. And obviously the grinder itself is spinning at a speed the maker desired.

So that leaves the tools you are sharpening.

Best advice I can give anyone is that grinding speed and precision are mutually exclusive. If you need precision, you can't have speed. And if you need speed, you can't have precision.

So, if you are sharpening a shovel, a bench grinder is a good use for that. But it's a terrible choice anywhere you need a keen edge unless you get a specialty set specifically designed for the purpose (i.e. the paper discs and such).

We went to different shovel sharpening schools....

 

[Hohn]

We went to different shovel sharpening schools....

Maybe that’s why I keep going through shovels? HAHAHA.

 

[Treeman]

Delete, double post

 

[Treeman]

So I don't think the touch pad is unreliable per se. But why take the risk when a basic toggle switch is bombproof and easily replaced?
Personally in your situation, I would go with a reasonably quality (Dayton?) fixed speed, toggle-switch 8" .............................

Yikes, the JET does not have an adjustable angle tool rest, which I really liked on my old beast. This might be a deal breaker.

At your suggestion, looking at a Dayton now: https://www.grainger.com/product/2LKR9?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231&gQT=1

Dang, not too many heavy duty grinders out there in the $500 +/- range.

 

[Beerhippie]

Yikes, the JET does not have an adjustable angle tool rest, which I really liked on my old beast. This might be a deal breaker.

At your suggestion, looking at a Dayton now:https://www.grainger.com/product/2LKR9?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231&gQT=1

Dang, not too many heavy duty grinders out there under $500.

An adjustable angle tool rest is easily fabricated. All you need are cutting tools and a good, high-power grinder with an... aawww, fuggitabout it.

 

[Treeman]

An adjustable angle tool rest is easily fabricated. All you need are cutting tools and a good, high-power grinder with an... aawww, fuggitabout it.

I thought the same, but this is at a workplace and modifications would be subject to our litigious society.

Jet has a 1750rpm "woodworkers" model with adjustable angle tool rest. Maybe I could swap tool rest or go with this slower, less HP/amp Jet.

https://jettools.com/jwbg-8nw-8-ww-bench-grinder-without-wheels

I have choices narrowed to Dayton vs Jet. 1750 RPM vs 3400 RPM. 1750 will do both sharpening and grinding (slower) vs. 3400.
Thanks all - the input has assisted decision making.

 

[Hohn]

Dang, not too many heavy duty grinders out there in the $500 +/- range.

That’s seemingly so many things now: prosumer level stuff is often pushed down to consumer or up to pro/industrial.

Not much between the throwaway end and the industrial end in many cases.

 

[RoninB4]

-RPM (SFPM) shouldn't be the deciding factor in choosing a grinder other than the maximum speed limit for any given wheel. Torque is good if you have heavy metal removal to do. What does make a big difference is the type of abrasive wheel chosen, the grit particle size, and how hard/soft the wheel is. These will all affect the metal removal rate and how much heat is generated. You'll always have heat control to wrestle with so either use a spray/drip system or just have a container of water on hand for heat control. I've done a lot of tool (by hand) and precision grinding (surface/OD/ID) and heat is always something to factor in. There's a huge variety of abrasive types, pick one that suits your needs and budget. Most general purpose bench grinders use a carborundum abrasive, I prefer an aluminum oxide wheel most of the time. Get some type of wheel dresser and use it to avoid clogging/glazing the wheel.

 

[seber]

Most general purpose bench grinders use a carborundum abrasive, I prefer an aluminum oxide wheel most of the time. Get some type of wheel dresser and use it to avoid clogging/glazing the wheel.

Good advice on the wheel dresser. But one thing I would caution about is do not get the rotary type. They work but diamond point or diamond matrix will do a much better job of it. They will only take as much as you determine to be sufficient and can be very precise for square corners or custom profile.

 

[RoninB4]

Good advice on the wheel dresser. But one thing I would caution about is do not get the rotary type. They work but diamond point or diamond matrix will do a much better job of it.

-Diamonds used in dressing a grinding wheel are not really suitable for use as a hand held dresser. Why is that? The uncontrolled depth and/or rate of the "dress" can/will generate a lot of heat. Diamonds are often embedded in a substance similar to silver solder. Once the solder softens due to heat it can let go, causing the diamond(s) to launch. Bench grinders aren't really used for precision work anyway so using a "star/wheel", a purpose made stone (silicon carbide), or even a Norbide stick is better. Proper ventilation or mask is advised due to the abrasive particles that will be spewed into the air. They won't impart as finely dressed a surface to the wheel but bench grinding isn't a precision process anyway unless you have an apparatus/attachment that will control depth and cross feed.

They will only take as much as you determine to be sufficient and can be very precise for square corners or custom profile.

-Dressing a grinding wheel with diamonds is customary with precision grinders (surface, OD/ID/ segmented wheel/ etc.) that can control the diamond-to-wheel engagement. The size/shape of the diamond(s) will also determine that depth of dressing engagement. I'll have to admit that I've launched a couple of diamonds because I took too great a depth of engagement to the wheel, overheated the holder, and the embedded solder let the diamond fly. Dressing a tiny concave radius on the wheel with an even tinier diamond can be sketchy.

 

[Treeman]

-RPM (SFPM) shouldn't be the deciding factor in choosing a grinder other than the maximum speed limit for any given wheel. Torque is good if you have heavy metal removal to do. What does make a big difference is the type of abrasive wheel chosen, the grit particle size, and how hard/soft the wheel is. These will all affect the metal removal rate and how much heat is generated. You'll always have heat control to wrestle with so either use a spray/drip system or just have a container of water on hand for heat control. I've done a lot of tool (by hand) and precision grinding (surface/OD/ID) and heat is always something to factor in. There's a huge variety of abrasive types, pick one that suits your needs and budget. Most general purpose bench grinders use a carborundum abrasive, I prefer an aluminum oxide wheel most of the time. Get some type of wheel dresser and use it to avoid clogging/glazing the wheel.

Thank you. I only have experience with my old 1750rpm 10 inch behemoth grinder for general farm shop use - grinding parts for welding, shaping, fitting, etc.. I DID sharpen my mower blades, using water cooling, but no other precision sharpening.

You are saying that moving to a 3400rpm 8" grinder should not be a concern? If careful, can I still sharpen mower blades (gentle & cool). Thanks for the abrasive wheel advice. I also enjoy using a wire wheel to clean up parts.

 

[RoninB4]

Thank you. I only have experience with my old 1750rpm 10 inch behemoth grinder for general shop use - grinding parts for welding, shaping, fitting, etc.. I DID sharpen my mower blades, using water cooling, but no other precision sharpening.

-It probably did a terrific job for you. I have a few precision grinders but sometimes wish I had a 1750 rpm 10 inch behemoth like yours.

You are saying that moving to a 3400rpm 8" grinder should not be a concern? If careful, can I still sharpen mower blades (gentle & cool). Thanks for the abrasive wheel advice.

-I think that checking the grinding wheels you intend to use will help you decide. Some are far more expensive than others for long term replacement costs. Spindle size often dictates your wheel selection, less made equals more expensive. A lot will also depend upon just what you'll use this for. I doubt that you'll want a 100 grit wheel (yes I'm being ridiculous) for the bench grinder but what you'll use the grinder for narrows the selection choices. There's also cup wheels, cut-off wheels, wire wheels, etc. that will have an availability based upon spindle diameter as well as maximum rpm. We all work differently and use different methods so it's a bit difficult to give you definitive advice. For example, I sharpen mower blades with an angle grinder and finish up the edge with either a file or a stone. When sharpening lathe bits I'll use a bench grinder but it it's a lathe bit for cutting threads I'll insist upon using the surface grinder for geometry and a keener cutting edge. What should you use? How much material needs removing? How fast do you want to do it? How fussy should the mower blades be? How fussy should wood chisels be? How about metal chisels? Grinding is a series of compromises that's often personal choices. I often prefer to swap wheels for some work, sometimes I just want a one-wheel-does-it-all situation. I'd probably be inclined to check availability, price, and maximum wheel speed as deciding factors. More torque for heavier grinding and wire wheel duty. Maximum wheel speed specs should be considered critical and not just the safety nazis warning. Exceeding wheel speed specs is a dangerous affair, when a wheel comes apart it's a scary thing. I've used mounted wheels in jig grinders that spun up to 20k rpm but only when the wheel was rated for it. Diamond and CBN wheels can/should run faster than aluminum oxide wheels but running an aluminum oxide wheel faster than recommended (not the same as maximum rpm) will cause the wheel to act harder than it is and grinding will be more difficult. Choose the wheels you expect to run, evaluate the costs for replacement wheels, size the spindle diameter/rpm on these. Oh an DO NOT purchase used grinding wheels unless you know how to test for a cracked wheel. Grinding wheels are fragile and can develop cracks from mishandling you won't see but they'll explode when they get up to speed.

 

[seber]

There are literally hundreds of these hand held diamond dressers available. They are made to be used by hand, not by machine. In many decades of using them, I have never had a diamond come loose.

-Diamonds used in dressing a grinding wheel are not really suitable for use as a hand held dresser. Why is that? The uncontrolled depth and/or rate of the "dress" can/will generate a lot of heat. Diamonds are often embedded in a substance similar to silver solder. Once the solder softens due to heat it can let go, causing the diamond(s) to launch. Bench grinders aren't really used for precision work anyway so using a "star/wheel", a purpose made stone (silicon carbide), or even a Norbide stick is better. Proper ventilation or mask is advised due to the abrasive particles that will be spewed into the air. They won't impart as finely dressed a surface to the wheel but bench grinding isn't a precision process anyway unless you have an apparatus/attachment that will control depth and cross feed.

-Dressing a grinding wheel with diamonds is customary with precision grinders (surface, OD/ID/ segmented wheel/ etc.) that can control the diamond-to-wheel engagement. The size/shape of the diamond(s) will also determine that depth of dressing engagement. I'll have to admit that I've launched a couple of diamonds because I took too great a depth of engagement to the wheel, overheated the holder, and the embedded solder let the diamond fly. Dressing a tiny concave radius on the wheel with an even tinier diamond can be sketchy.

 

[RoninB4]

There are literally hundreds of these hand held diamond dressers available. They are made to be used by hand, not by machine. In many decades of using them, I have never had a diamond come loose.

-Well they clearly ARE intended for hand held use. I've never seen one used or even present in all the shops I've worked in so I can't really have an opinion one way or another about them. What was commonly used in machine shops are the dressers I've mentioned in my previous post. The price seems acceptable from doing a quick check so I suppose the longevity is the only real question. My previous comments regarding the diamond(s) coming loose from heat are about single point and cluster types used for precision grinding applications. Thanks for posting.