Contact Wheels for 2×72 Grinders

There are a lot of requests and questions regarding where to purchase contact wheels. As you know there are two types of contact wheels, smooth and serrated. They come in various diameters from 2″ to 14″ with 2″ widths. The most common sizes used are between 6 and 12 inches in diameter.

There are various suppliers in North American, with almost all of the suppliers in the USA.
L-Paladin in China, is one of many suppliers who sells contact wheels in Southeast Asia.

Enclosed are some links to the L-Paladin store on Aliexpress. The website states free shipping to Canada via DHL, but expect to pay Duty and Taxes on the Canadian value and possible handling fees from DHL. The site sells in various currencies and for us Canadians, you can pick CDN dollars.

If you are using 1/2″ axle bolts, you must pick “For 6202 Bearings” The wheels come with a Cir-clips installed. You can purchase bearings and Grade 8 axle bolts from Nexus Grinders and install them yourself or have one of your local business press them in for you. You could also install a spacer between the bearings using DOM material with a 1/2″ inside diameter. The website also states that the wheels are Dynamically Balanced.

L-Paladin Links
150 x 50 mm (6″ x 2″) Serrated Rubber contact Wheel   *Sale price Can $46.10
200 x 50 mm (8″ x 2″) Serrated Rubber Contact Wheel   *Sale price Can $54.06
250 x 50 mm (10″ x 2″) Serrated Rubber Contact Wheel  *Sale price Can $85.68
300 x 50 mm (12″ x 2″) Serrated Rubber Contact Wheel  *Sale price Can $90.98
* sale price on January 5, 2019

I am not endorsing the above company. Do your own research and be informed before you purchase from any supplier. I am only providing the above links for your reference. If you have purchased smooth or serrated wheels from L-Paladin or any other Canadian or USA supplier, please provide me with some feedback so that we can update the blog for others.

Tracking Mechanism

When you start a new business, one of the challenges is finding the time to research, design, build and test new products. This week, I took some time to bench test our new 2 axis tracking mechanism. Although I usually leave the items in its raw steel state during testing, I added the pieces to the last order of powder coating. Well today, I started the bench testing and it performed exactly as it was designed. This new 2 axis tracking mechanism will make setup of all of the NG models for everyone. It will also allow for the fine adjustment when adding other attachments or for you blade smiths who like to run belts backwards.

Enclosed is short video demonstrating the fine tuning with the 2 axis tracking mechanism. The belt was purposely setup to be running into the grinder to demonstrate how the new mechanism works. The tracking wheel was set at 90 degrees from the frame. Adjusting the two socket cap screws allows the belt to be moved back to the centre of the tracking wheel and idler wheels. Once you have it dialled in, tighten the two screws and you’re done. This tracking mechanism allows you to adjust the tracking wheel in two different planes which makes setup so much easier.

UPDATE: The new 2 axis tracking mechanism is now being installed on all Nexus Grinders.

Bench Testing the Nexus 2 Axis Tracking Mechanism



Drive Wheel and Belt Speeds

If you have the resources to build or purchase a variable speed 2×72 belt grinder with a variable frequency drive (VFD), you will have a grinder that has the versatility to grind metal at higher speeds and to run slower with small steel wheel sets.

The next best option is a grinder with step pulleys that will give you up to 4 different speeds depending on the pulleys you use.  I recommend you use cast iron pulleys vs. aluminum as they have less vibration at higher speeds.

If you use a grinder with a fixed speed RPM, here is a link to the Surface Feet Per Minute you can expect from 4″, 5″ or 6″ drive wheels used with 1800 or 3600 RPM motors.
  Wheel Speed SFPM

Installing Aluminum Wheels on your Grinder

Installation of Nexus Aluminum Grinder Wheels

The drive wheels have a 5/8 inside diameter bore with a keyway and an 1/8” setscrew.

  1. Try the 4” or 5″ drive wheel on the shaft without the steel key to ensure that the wheel slides easily onto the motor shaft or pulley shaft.
  2. If the drive wheel doesn’t slip on, use some 300 or 400 grit emery cloth on the shaft while it is spinning slowly. Only apply the sandpaper onto the shaft for a few seconds at a time. Stop the spinning wheel, then wipe any grit off of the shaft and try sliding the wheel back on.
  3. If it’s still too tight, repeat step four (2) until it slides on easily.
  4. When installing the drive wheel onto the motor shaft or pulley shaft, make sure that the key way is aligned up properly with the wheel and shaft.
  5. If the key is too large, remove the steel key and grind or file it down so that the drive wheel slides on easily.
  6. Never hammer the drive wheel onto the motor shaft as this may damage the motor and/or bearings.
  7. The drive wheel should just slide on with some taps with your hand.
  8. Use an 1/8” hex key or Allen wrench to tighten the set screw onto the motor shaft.

Should you encounter a drive wheel that you are unable to remove by hand, a gear puller will assist you to remove the drive wheel without damaging your motor and/or bearings.

The 2” idler wheels and the 3” tracking wheel have a steel spacer between the bearings to prevent overtightening.

  1. Tighten the axle bolts by hand into the D-Plate or Tracking Wheel Mechanism.
  2. Using ¾” wrenches to lock the nyloc nut in place.
  3. Only tighten the axle bolts so that the wheel has no side to side movement. When spinning the wheel, the washer (machine bushing) should be in contact with the inner race of the bearing. The wheel should still spin freely by hand.  If it doesn’t spin freely, back off the nyloc nut and loosen off the bolt. Retighten the nyloc nut and spin the wheel again until the wheel spins freely.
  4. For the tracking wheel, the jam nut should be snug so that there is no side to side movement of the tracking wheel on the axle bolt. Tighten the bolt so that the jam nut is tight against the swivel. The wheel should still spin freely by hand.  If it doesn’t spin freely, back off the bolt and jam nut, re-adjust and tighten the bolt and jam nut and ensure the wheel spins freely.

The 6202 bearings are sealed and do not require lubrication. Overspinning the wheels will cause the bearings to fail prematurely.  If lubrication is leaking outside of the seal, the bearing is starting to fail or has failed and should be replaced immediately. You can buy replacement bearings at a reasonable cost.

Motors and Variable Frequency Drives

There are many different options and recommendations on what motors and VFD’s to use on a 2×72 Belt Grinder.  We have put together a simplified version of recommend options to use on the Nexus Grinders.  This by no means are the only options for motors or VFD’s.  Do your research and become informed on what is needed to power and control a 2×72 belt grinder.

The key factor for determining what size motor and/or VFD to use will depend on what power you have available in your shop or garage.
If you only have 115 volt supply, you will be looking at using 1.0 to 1.5 horsepower motors.
If you have 230 volt supply, you will be looking at using 1.5 to 2.0 horsepower motors.  You can go with larger horsepower motors, but you will need a larger rated VFD which will increase costs.

Motors
If you use a 56C  frame motor with a foot mount, you can use the C face mount for the NG-lll and with the foot mount you could use it for the NG-l and NG-ll grinders.  Most motors now days offer both a C face and a foot mount.  If you don’t have one or can’t find one, make sure you obtain the correct motor mount for the Grinder. Automation Direct in the USA has free shipping to Canada and their prices are good. There are many other suppliers in Canada and the USA, so please shop around.

You want to use Total Enclosed Fan Cool (TEFC) motors. Open motors are a poor choice, as grinding dust will get inside of the motor and it will eventually fail.
If you are using a 4” drive wheel, you will want a 3600 rpm motor.
You should also look for motors that are electronically reversible.
If you are using a VFD, you will need a 3-phase motor. (see VFD notes below).
If you want to use a counter shaft with pillow blocks, sheaves (pulleys) and belt, you can use a 1.5 horsepower, single phase motor. You can only use this type of setup with the NG-l and NG-ll models.

Variable Frequency Drives
Variable Frequency Drives are commonly referred to VFD’s.
If you want to use a VFD, you must use a 3-phase motor.
VFD’s convert single phase 115 or 230 volt inputs into 3-phase outputs to the motor.
You can’t use a single-phase motor on a VFD.
VFD’s control speed and some may also allow you to use forward and reverse settings.
You can’t use a motor that is rated higher than the VFD rating. You can use a higher rated VFD with a lower rated motor. So you can use a 2.0 horsepower VFD with a 1.0 to 2.0 horsepower 3 phase motors.  You should not use a 3.0 horsepower motor with a 2.0 horsepower rated VFD.

There are many manufactures of VFD’s, so look for a VFD with a NEMA 4-X protection rating which is sealed from dust, water and a corrosion resistant exterior. If you use a VFD with NEMA 1 rating, you will need to protect the drive and provide a fan and filter to keep the drive cool and to not allow grinding dust to penetrate your VFD.  In the end, it’s not much more money and definitely worth your time to buy a NEMA 4-X rated VFD.

KB Electronics sells many models of VFD’s.  You can buy KBAC drives in the USA and Canada.
If you purchase the KBAC-27D model, you can use the VFD with the 115 and 230 volt inputs and can use 1.0 horsepower, 1.5 horsepower and 2.0 horse power, 3-phase motors.

The 115 volt input you can use a 1.0 or 1.5 (maximum) horsepower, 3-phase motor.
The 230 volt input you can use a 1.0, 1.5. or 2.0 horsepower, 3-phase motor.

AC line input 115 volts, maximum current 22 amps, and a 25 amp circuit breaker.
AC line input 230 volts, maximum current 16.7 amps, and a 20 amp circuit breaker. Make sure you have the required power supply and circuits available. See Table 2 on page 7 kbac_manual

If you use the KBAC-24D model you are limited to a maximum of 1.0 horsepower, 3-phase motor.
AC line input 115 volts, maximum current is 14.4 amps and a 20 amp circuit breaker. Make sure you have the required power supply and circuit available.

The KBAC VFD’s are rated NEMA 4-X. You can also add an optional forward and reverse switch along with a line switch.

Recommendations:
Now that you have learned a lot about motors and VFD’s. Here are some recommendations we have put together to assist you in making your decision.

Option 1
1.5 horsepower or 2.0 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount.
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” Direct Drive Wheel)
Variable Frequency Drive (VFD) KBAC 27D 230 volt single-phase input(rated up to 2 hp).

Option 2
1.0 to 1.5 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount.
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” Direct Drive Wheel)
Variable Frequency Drive (VFD) KBAC 27D 115 volt single-phase input (rated up to 2 hp).

Option 3
1.0 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount.
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” Direct Drive Wheel)
Variable Frequency Drive (VFD) KBAC 24D 115 volt single-phase input (rated up to 1 hp).

Option 4
1.5 horsepower, 115 volt, single-phase motor.
56C or 56HC flange Mount.
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” Drive Wheel)
Counter-shaft, with pulleys and belt

Enclosed is some information on motors from Automation Direct

1 hp 1-phase
IronHorse standard performance AC induction motor, general purpose, 1hp, 1-phase, 115/230 VAC, 3600rpm, TEFC, 56C frame, rolled steel, rigid base/C-face mount.MTR2-001-1AB36

1.5 hp 1-phase
IronHorse standard performance AC induction motor, general purpose, 1-1/2hp, 1-phase, 115/230 VAC, 3600rpm, TEFC, 56C frame, rolled steel, rigid base/C-face mount.MTR2-1P5-1AB36

2.0 hp 1-phase
IronHorse standard performance AC induction motor, general purpose, 2hp, 1-phase, 115/230 VAC, 3600rpm, TEFC, 56HC frame, rolled steel, rigid base/C-face mount.MTR2-002-1AB36

1.0 hp 3-phase (use KBAC24D or KBAC27D
IronHorse premium efficiency AC induction motor, general purpose, 1hp, 3-phase, 208-230/460 VAC, 3600rpm, TEFC, 56C/HC frame, rolled steel, rigid base/C-face mount.MTRP-001-3BD36

1.5 hp 3-phase (use KBAC27D)
IronHorse premium efficiency AC induction motor, general purpose, 1-1/2hp, 3-phase, 208-230/460 VAC, 3600rpm, TEFC, 56C/HC frame, rolled steel, rigid base/C-face mount.MTRP-1P5-3BD36

2.0 hp 3-phase (use KBAC27D)
IronHorse premium efficiency AC induction motor, general purpose, 2hp, 3-phase, 208-230/460 VAC, 3600rpm, TEFC, 56C/HC frame, rolled steel, rigid base/C-face mount.MTRP-002-3BD36 

3.0 hp 3-phase (use KBAC29(1P))
IronHorse premium efficiency AC induction motor, general purpose, 3hp, 3-phase, 208-230/460 VAC, 3600rpm, TEFC, 56C/HC frame, rolled steel, rigid base/C-face mount.MTRP-003-3BD36

References:
Note: Nexus Grinders has no affiliations with KB Electronics or Automation Direct.  These are provided as examples and a starting point for your research.

For KBAC drives, please review the manual available at KB Electronics or call them at 1-888-637-7333. https://www.kbelectronics.com
For Automation Direct motors, please review the manual available on their website or phone 1-800-633-0405. https://www.automationdirect.com

There are many suppliers for motors and VFD’s.  Please research and shop around for what best suits your needs.

Warning:
Working on electrical circuits or incorrectly connecting electrical equipment can be extremely hazardous. Please consult with qualified electrician and qualified personnel if you are unsure how to make safe electrical connections.  Electrical connections should meet or exceed National, Provincial, and local electrical codes. Always refer to the manufacture’s manuals and installation instructions. You may need permits if you are making changes or adding circuits to your electrical panel. Please check with your local authorities before starting any electrical connections.