Low Cost Industrial Bench Grinder

Updated 7/2/2020. After 8 years of frequent use the “stationary switch” inside of my Dayton 2LKR9 grinder wore out. i.e. the switch that cuts out the motor start capacitor after the motor comes up to speed. (Not the main on/off switch). It is the thing that goes “click” after the grinder starts up.

I am happy to report that replacing the switch turned out to be a pleasant experience. Yea, I would have liked to avoid it. But, working on something that was designed to be taken apart and repaired was a real joy.

A new “stationary switch” cost me $41 with shipping on 6/2020. For more info see “Stationary Switch Replacement” below.

After taking the grinder and motor all apart, I known there is no cheap plastic crap inside of this grinder. The bearings, etc are really good quality.

I really wish I did not “smoke” the grinder. I knew there was something wrong with grinder for a few weeks. It did not sound right when it started up. The familiar click was gone or muted. But, I was busy turning! I did not open up the grinder until after I saw smoke. I got away with it. Just melted some coil bindings rather than the actual copper coils. However, I probably shortened the life of the grinder. I feel like an idiot because replacing the failing switch was an easy job.

Note: The main on/off switch failed several years ago. I easily replaced it with one from my local hardware store.

Updated 3/18/2020. I still love this grinder. It is still available from Zoro # G1762144. The price has gone up to $318. I still think that is a great price.

The newer versions of Dayton 2LKR9 grinder are light gray. Rather than dark gray. I changed the photo below to the new color.

If you want a slow speed grinder then I would go with a $125 Rikon 80-805, 1/2 HP, 8” Slow Speed Bench Grinder from Amazon. Or a $245 Rikon 80-809, 1 HP, 8” Slow Speed Bench Grinder from Amazon. But you don’t really need 1 HP.

I love my new bench grinder!   I purchased it in Sept of 2012.

I had to replace a 10 year old Delta 8″ bench grinder that was giving me trouble.

 


 
The Grinder

It is a Dayton Bench Grinder model # 2LKR9.   8″ x 1″ wheels, 3450 RPM, 3/4 hp, 120 volts, 7 amps.

It only cost me $210 from Zozo Tools on the web.  This is a very good price for an industrial quality grinder.  This grinder comes with a cast iron base and impressive cast iron wheel guards.  Good quality 3/4 HP motor.

When I first powered on this grinder on I got this “WOW” feeling.   This is a quality tool!   It runs really smooth and sounds great!   You just want to turn on the grinder and admire it!

The grinder comes up to speed fast when turned on and coasts for a long time after you turn it off.

I really like the 21″ width of this grinder.  When grinding a tool, I don’t have trouble with the tool handle or my hand hitting the “other” wheel. The center to center distance between the wheels is 16.5″.

Beware! The grinder comes with dust collection hoses.  Metal working dust collectors are explosion proof.  Woodworking dust collectors are not explosion proof and thus CAN NOT be used.  I just discarded the dust hoses.

Grinding Wheels

The 8″ grinding wheels that come with the grinder are better than the low quality ones that typically come with cheap grinders.

On cheap grinders you mount the grinding wheels onto the motor shaft by pushing them up against a washer or C ring.  The washers flop around and make it hard to mount the wheel so it runs really true.

The wheels on this grinder run really true!  Because, the grinder comes with these fancy aluminum “Inner Wheel Flanges” that slip over the shaft.  The flanges have a wide face that registers against the wheel on one end, while the other end extends back down the shaft into the grinder where it registers up against the motor.

I now recommend CBN grinding wheels for newbies. See my CBN Grinder Wheels blog entry. Thus what follows about stone wheels is now obsolete.

You can’t teach and old dog new tricks.  So, I decided to replace one of the grinding wheels with my favorite grinding wheel.  A Norton 8″ x 1″ x 1″, Gemini, Alundum (Aluminum Oxide), 100 Grit, Fine, Grinding Wheel.  In some places it is listed as 100/120 grit.  Norton part# 88280 or part# 07660788280.  Zoro part# G12205592, stock# 6A092.  Beware, this wheel use to be a gray color with a colorful “Gemini” label on it.   Norton has changed the color and packaging.  The wheel is now a brown color with a boring blue Norton label.  Same great wheel!  Not to soft and not to hard.  Not to fine and not to course.

I can’t find the above wheel on Zoro. You can now get it on Amazon as Norton 88280 8″X 1″X 1″ Gemini Alundum Bench Wheel Brown A/O 100/120 Fine (1 Wheel). For $38 on 3/18/2020.

 


cbf_grinder_2013_01_stand_08

Use Drill Bushings

You don’t need Drill Bushings with CBN wheels.

Most 8″ grinding wheels come with a 1″ mounting hole and these plastic bushings so you can mount them on a grinder with 5/8″ diameter shaft.  The nested plastic bushings may cause wobble.

I use steel Type “P” Drill Bushings rather than plastic bushings.   There are precision ground to 0.0014″ tolerance. Type “P” = Headless Press Fit.  1″ outside diameter, 5/8″ inside diameter, 1″ long.

 


2 of Zoro part# G3591761, or Mcmaster-Carr part# 8491A562

The Tool Rests

The tool rests that come with  grinder are better than average.  But, I discarded them because I really like the Wolverine Grinding system from Oneway.

See my Wolverine Grinder Jig Setup blog entry for more info. It also shows how I strongly recommend you set up your grinder and Wolverine system.

Cheap Grinders Cost More!

The wheels on this grinder run true!   Thus this grinder does not require those fancy Wolverine Wheel Balancers from Oneway.

Other 8″ grinders go for $120 to $150.  Wheel balancers are $70 each.

$120 + $70 + $70 is $260.   My new grinder was only $210.

10 years ago you could buy a cheap grinder that did not require wheel balancers to run true.  It seems those days are long gone.

Not Variable Speed

I was looking for a 2 speed or variable speed grinder when I found this grinder.  I wanted 1725 rpm to 3450 rpm.  I could not find a good or even reasonable quality 8″ variable speed bench grinder.  I decided to live with this 3450 rpm grinder because I liked the quality and I personally only use 3450 rpm.  The variable speed was for my friends and students.

Dayton does make a very similar 8″ variable speed grinder model #2FDB6. But it is 1.5 hp and thus costs $470. To much!   It also makes a similar 1725 rpm grinder model #2LKT2.  But it uses 10″ wheels.  To large! No good!

I only like 8″ grinders. I do not like 6″ grinders.   I can’t grind my tools to the shapes I like on a grinder with 6″ wheels.  If 6″ is ok with you then Dayton does make a similar 6″ variable speed grinder model
#2FDB5 for $278.  Beware!  Dayton makes other 6″ grinders but the wheels are not 1″ wide.  They are  only 3/4″ of an inch wide.  To narrow!

Zoro Tools

I found Zoro Tools on the web.  http://www.zorotools.com/

I have purchased a few things from them.  Low prices!  No problems.

My New Grinder Stand

I mounted my new grinder on a new grinder stand.  It’s my 2nd generation stand.  My 1st generation stand was good. This one is even better.   A friend was over last week and, he really liked the height of my grinder.  Center of grinder wheel is 46″ off the floor.

I like having my grinder mounted on a stand that I can easily move around the shop as needed.  My new stand is built on a base I purchased from Grizzly tools a long time ago.  It is 32″ tall.  I just saw a very similar stand for less at Harbor Freight.

Here is what my new stand looks like:

 

cbf_grinder_2013_01_stand_02

 

More photos are here: http://www.carlford.info/blog_images/cbf_grinder_stand

The stand is made out of 3/4″ local hardware store plywood. I buy the better, almost cabinet grade $38 plywood.  The stand is sturdy because I lock the plywood pieces together with 3/4″ wide by 1/4″ deep dado groves. All joints are glued and screwed.  All exposed plywood edges are belt sanded before assembly so they look nice. Sizes: Top platform 19″ wide by 11″, Middle platform 20″ wide by 10″, Bottom platform 20″ wide by 13″, Back 8″ wide by 19.5″, Middle platform supports are 9.5″ wide by 6.25″ + 0.5″ for dados.

Stationary Switch Replacement

The “stationary switch” inside of the Dayton 2LKR9 grinder is the switch that cuts out the motor start capacitor after the motor comes up to speed. (Not the main on/off switch). It is the thing that goes “click” after the grinder starts up.

If the “Stationary Switch” in your grinder fails then replacing it is not a beginners project. But it is really not that hard. You will need some standard basic tools and a cheap 2 or 3 jaw gear puller to remove a bearing. I found working on something that was designed to be taken apart and repaired was a real joy.

If you are not up to the task then most towns have places that repair motors for the sewer plant, etc. Look in the local yellow pages under “electric motor repair”.

If you are going to do it yourself. Then here are some tips. I am going to assume you don’t need step by step directions.

Inside the Motor

Here is what the inside of the motor looks like after you remove the end caps, etc. The red arrow in photo points to the stationary switch. The green arrow points to the gold thing on the shaft with springs. It activates (pushes) the stationary switch via centrifugal force when the motor comes up to speed. The red arrow points to the bearing that you need to remove to get to the switch.

Beware! Mark the exact location of the gold thing on the shaft with a triangle file BEFORE removing it.

The Stationary Switch

Here is what the stationary switch looks like. My old worn out one is on the left. You can see that the metal simply snapped after lots of use. The new part is on the right.

Replacement Part

The parts diagram for the 2LKR9 grinder shows the stationary switch is item #52, part number 25171.00. A google search on “dayton 25171 stationary switch” easily found the part available at several dealers. I got mine from Grainger for $41 on 6/2020 ($27 + taxes and shipping).

Gear Puller

You are going to need a 2 or 3 jaw gear puller to remove the bearing. I already had one, but the jaws were not long enough. So, I had to make new longer connector bars. You can purchase a cheap one for around $25 on Amazon, etc.

Note: You can also purchase a dedicated “bearing puller”. They may not be designed to work with the long shaft on this grinder. A gear puller gets the job done and will probably be more useful on future projects. Making your own connector bars, etc is not an option with most bearing puller designs.