Simington Square Chain Grinders (Bench Test)
A useful bench test starts by identifying the exact Simington grinder and matching its wheel, power supply, and vise setup to the manual. Then inspect the machine, run it unloaded with the guard in place, and test a known chain using light passes. Check cutter shape and consistency; stop if the wheel vibrates, rubs, or acts oddly.
“A cutter can look sharp and still cut unevenly if the left and right sides do not match.” That is the problem a careful grinder test should catch. The goal is not to prove that every Simington grinder shares the same settings. It is to confirm that your specific machine runs safely and can produce repeatable square-ground cutters on the chain you intend to sharpen.
This is a bench-test procedure, not a report of measured results from one identified machine. Simington models, electrical ratings, and approved wheels can differ. Without the exact model and its manual, no one can responsibly give you a universal wheel size, arbor size, grinder angle, or electrical rating. Use the steps below to gather those details and test the setup without guessing.
Equipment Setup and Bench Safety
A bench test checks the grinder’s condition and basic operation before you grind a chain. Start with the model nameplate and manual, not a setting copied from another grinder. Record the machine’s exact model and serial number, then use its manual to confirm electrical limits, wheel requirements, setup controls, and safe operating steps.
Identify the grinder and chain
With the machine unplugged, find its nameplate and record the model and serial number. Check the manual for the listed voltage, frequency, phase, and current rating. Use a grounded supply and overcurrent protection suited to the machine’s rating. Do not assume that two machines with similar names use the same supply or parts.
Record the chain details too: manufacturer and model, pitch, gauge, cutter style, and drive-link count. Pitch describes the spacing between chain rivets; gauge is the width of the drive links that fit the bar groove. A 3/8-inch pitch and .050-inch gauge chain is only an example, not proof of compatibility with a particular grinder or vise.
| Test item | What to confirm | Stop if |
|---|---|---|
| Grinder identity | Exact model and serial number | Nameplate is missing or unreadable and specifications cannot be confirmed |
| Power | Supply matches nameplate voltage, frequency, phase, and current | Rating or supply is uncertain |
| Wheel | Type, dimensions, bore, and RPM match the manual | Wheel is damaged, wrong size, or under-rated |
| Chain | Pitch, gauge, cutter style, and drive links are identified | Chain will not sit securely in the vise |
Inspect before connecting power
Secure the grinder to a stable bench as directed by its manual. Check that the guard is intact and fitted, the switch works normally, and the cord has no cuts or exposed conductors. Inspect the vise, clamp, and adjustments for damage or looseness. The chain must be held by the machine’s restraint, never by hand.
Wear safety glasses and a face shield, plus hearing protection. Tie back long hair and secure loose clothing. Remove nearby items that could catch or obstruct movement. Before installing a wheel, check that its type, dimensions, bore, and maximum speed are approved for the exact grinder. The wheel’s marked maximum RPM must be at least the spindle RPM specified for that machine.
Do not use a cracked, dropped, chipped, or otherwise damaged wheel. A wheel failure at speed can cause severe injury. A ring test alone does not approve a wheel that the machine maker does not specify. If the manual is unavailable or wheel compatibility is unclear, pause and obtain the correct information rather than trying the wheel.
Square-Chain Grinding and Inspection
Square-chain grinding forms a cutting edge for square-ground cutters; it is not the same setup as hand filing a round-ground chain. Grinder angles, vise position, and wheel clearances depend on the chain and machine instructions. Set those controls from the chain maker’s specification and the exact grinder manual, not from a generic filing chart.
Run the unloaded grinder first
Install and dress the approved wheel as the manual directs. Confirm it is seated correctly, the guard is in place, and the chain vise and wheel have clearance through the full travel. With the machine unplugged, move the head through its intended range and check for contact or binding.
Clear the work area, stand out of the wheel’s plane, then run the grinder briefly with no chain engaged. Keep the guard installed. Stop at once if you hear unusual noise or see vibration, wobble, or rubbing. Switch off, wait for the wheel to stop completely, and unplug before checking anything. Do not remove the guard for a test run.
Set up and make a controlled test cut
Use a chain that matches the grinder’s vise and the wheel setup. Follow the manual to set cutter angles, vise position, and stops. A depth stop limits how far the wheel travels; set it so the wheel removes only the material needed for the cutter, rather than forcing a heavy cut.
Make light, controlled passes. Avoid prolonged contact that heats or discolors the cutter. Blueing is a warning that the steel has been overheated; stop and review the pressure, wheel condition, and setup. If the chain shifts in the vise or the result changes from cutter to cutter, stop and recheck the restraint and adjustments before continuing.
There is no universal square-grind angle or depth-gauge clearance. Do not substitute common chainsaw filing values. After sharpening, compare left-side and right-side cutters for similar length and shape. Check the depth gauges with the chain maker’s gauge and specification. Correct cutting geometry depends on the chain design, so a generic number is not a safe substitute.
Read the result, not just the spark
Sparks alone do not show whether the chain is correctly ground. Inspect the cutter faces under good light. Look for a consistent edge and similar shape across matching cutters, without obvious heat discoloration or uneven removal. If one side is noticeably different, check the vise position, angle settings, and wheel contact before grinding the rest of the chain.
| Bench observation | Possible area to check | Next step |
|---|---|---|
| Vibration or wheel wobble | Wheel condition, seating, or compatibility | Switch off, unplug, and inspect; do not continue |
| Wheel rubs during travel | Guard, setup, or clearance | Recheck the manual’s installation and clearance steps |
| Cutters differ side to side | Vise position, geometry, or chain restraint | Recheck settings against chain and grinder instructions |
| Cutter face is blue | Excess heat or overly aggressive contact | Stop; review wheel condition and use lighter passes |
| Chain moves in the vise | Clamp or chain positioning | Stop and secure it correctly before grinding |
Illustrative bench-test cases
These examples show how to use the checks; they are not measured results from a specific Simington model.
- Unknown wheel on a used grinder: The machine powers on, but the wheel markings do not clearly match the manual. Treat the setup as unverified. Do not run it until the wheel type, dimensions, bore, and speed rating are confirmed.
- Known chain, uneven cutters: The chain is secure, but cutter shape differs from one side to the other. Stop and compare vise position and angle settings with the chain specification. Do not compensate by taking heavier passes on the shorter cutters without first confirming the setup.
- Unloaded run sounds rough: The wheel seems to spin, but the grinder vibrates or makes a rubbing sound. Switch off and unplug it. Inspect the wheel and clearance; have the machine checked if the cause is not clear.
Maintenance, Wheel Care, and Setup Verification
A reliable grinder test includes the parts that hold and guide the chain, not only the motor. Wheel condition, vise security, and repeatable settings all affect the result. After every adjustment, check clearance and restraint again. Keep a record of the model, wheel details, chain identity, and settings used so future tests start from known information.
Dress the wheel and recheck the setup
Dress the wheel only by the method and with the tools specified by the grinder maker. Dressing restores the intended working surface; it does not make an incorrect wheel suitable for the machine. If the wheel is damaged or its identity is uncertain, replace it with an approved wheel rather than attempting to repair it.
Before each grinding session, check that the wheel is secure and the guard remains correctly fitted. Confirm the chain is held firmly and that the wheel clears the vise and chain through the full travel. If any adjustment changes, run the unloaded check again with the guard in place.
When the work is done, switch off and wait for the wheel to stop fully. Unplug before adjusting or cleaning. Use a suitable brush or vacuum for grinding debris. Inspect the wheel, guard, vise, and cord, then note any issue that needs attention before the next use. Do not clean or adjust while the machine is connected to power.
Storage and Seasonal Care
Good storage keeps the grinder and its setup ready for the next test. Switch off, let the wheel stop, and unplug the machine before cleaning or covering it. Store it in a dry place, protect the cord from cuts and crushing, and keep the manual and wheel specifications with the grinder.
Before using a machine after a long storage period, repeat the visual inspection and unloaded run. Check that the wheel remains approved and undamaged, the guard and vise are secure, and the power supply matches the nameplate. Storage does not replace inspection, and an old wheel should not be used if its condition or rating cannot be confirmed.
A sound bench test has a simple pass-or-stop decision. Continue only when the machine is identified, the correct wheel and supply are confirmed, the guard and vise work properly, and the unloaded run is smooth. Then grind a compatible chain with light passes and verify the cutters and depth gauges to the chain maker’s requirements.
Frequently asked questions
Can I use the same wheel on every Simington grinder?
No. Match wheel type, dimensions, bore, and maximum RPM to the exact model’s manual.
What wheel RPM rating is acceptable?
The wheel’s marked maximum RPM must be at least the grinder’s specified spindle RPM. Confirm both values before use.
Can I set square-ground chain angles from a standard filing chart?
No. Use the chain manufacturer’s geometry and the manual for your grinder. There is no universal square-grind setting.
Can I run the grinder with its guard removed to watch the wheel?
No. Keep the guard installed during operation, including an unloaded test.
Is a ring test enough to approve an unknown wheel?
No. It does not confirm that the wheel is the right type, size, bore, or speed rating for the machine.
Should I hold the chain by hand while grinding?
No. Use the grinder’s chain vise and restraint. Stop if the chain cannot be secured.
What should I do if the grinder vibrates?
Switch it off, wait for the wheel to stop, and unplug it. Inspect the wheel and its fit; do not continue until the cause is resolved.
Why are my cutters turning blue?
Blue discoloration indicates excessive heat. Stop and review the wheel, contact, and pass technique before continuing.
How do I check depth gauges after grinding?
Use the gauge and specification supplied or recommended by the chain maker. Do not use a generic clearance value.
What details should I write down for repeatable tests?
Record grinder model and serial number, wheel identification and rating, chain make and model, pitch, gauge, cutter style, and the manual-based settings used.
(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)
