How to Repair a Bench Grinder (8 Common Problems)
Replace or repair? That is the age-old question everyone asks including bench grinder owners. It is simple to replace a broken bench grinder but it may not be cost-effective. Repairing can save you money and keep you working since many repairs don‘t take a lot of time to do.
How to repair a bench grinder: One way to repair your bench grinder is to clean it first. All you have to do is make sure the grinder is not plugged in. Then you take a brush, cloth or even a toothbrush and clean out all the debris, dust and metal particles. Clean it thoroughly. Then when you are finished plug it back in again and test it out.
If it works, then you are good to go. If not, then you may have one of the 8 common problems listed below.
To find out the other 8 common problems and how to fix them, just continue to read our article.
Repairing a Bench Grinder 101
Bench Grinder Motor Problems
Bench grinders tend to break down once in a while. Here are some of the more common problems and their solutions.
1. It doesn’t turn on
There are 4 places on your bench grinder that can cause this problem. Your motor could have burned out, or the switch broke and won’t let you turn it on. Then the power cord broke, frayed, or burned out and last, your capacitor may be malfunctioning.
All you have to do here is identify the non-working part and get a brand new replacement for it. Your owner’s manual should have instructions to replace most of these parts.
2. Too much vibration
The culprits here are flanges, extensions, bearings, adapters, and shafts. These parts could have worn out, got bent or just didn’t fit right. Sometimes it is a combination of these items that cause the vibration.
To fix this issue, you will need to replace the damaged part or the part that does not fit. Make a thorough investigation to make sure it is not a combination of parts that are working together to cause the vibration.
3. The circuit breaker keeps tripping
The cause of this is the existence of a short in your bench grinder. The source for the short can be found in the motor, the power cord, the capacitor or the switch. Any of them can lose their integrity and cause a short.
To solve this issue, you have to identify the right cause and then replace the one at fault.
4. Overheating motor
Electrical motors do get hot. If they get too hot, then you will have 4 parts to look at as the source of the problem. The motor itself, the power cord, the wheel, and the bearings.
Once you discover which part causes the problem, you will have to replace that part.
5. Smoke
When you see smoke, that may mean that the switch, capacitor or the stator have shorted out and caused all the smoke. When this happens, you need to replace the faulty or broken part with a new one.
The wheel may also cause the bench grinder to smoke. That occurs when there is too much pressure applied to the wheel and the motor is working too hard to keep it spinning. You either have to replace the wheel or ease up on your pressure.
Bench Grinder Wheel Problems
Not all bench grinder problems are found in the grinder itself. Sometimes the grinding wheel can cause a lot of problems for you. Here are the most common ones and their solutions:
1. Grinding wheel wobbling
Again a variety of parts can individually or collectively contribute to this issue. If a nut is loose it may have lost its shape and would need replacing. If not, then it would just need to be tightened. The same goes for the collar. Check to see if it is loose and tighten it up if it is.
Finally, the shaft can cause this problem if it is bent. To solve this issue, you just need to get a new shaft and replace the old one.
2. Grinding wheel slips
The adapters and the shaft could have worn out giving too much play to the wheel. You would need to replace these parts to solve the problem. The nut could be loose and if it is, you just need to tighten it up a little. If it is stripped, etc., then you should replace it and make sure to tighten it enough.
The wheel could also cause this problem because it has an out of round bore. When this happens, you will need to replace the wheel.
3. Grinding or squealing sound
The first two sources are the adapters and the bearings. If they are worn out, then they will make noise and need to be replaced. The wheel and its guard could also make these noises.
In those cases you may need to move the guard back so it doesn’t touch anything and check the wheel to see if it is loose. If the wheel can’t be tightened, then you would need to replace it.
Answers to Your Questions
1. I have an old grinder, should I repair or replace it?
Sometimes repairing older grinders is not worth the trouble or the expense. In this case, replacing it would be the better option for you.
2. How do I true a grinder wheel?
The simplest way is to get a dresser and square off the wheel. This will help clean the wheel of any contaminants as well. Or you can get a jig and use that to help you make sure the wheels are square.
Some Final Comments
No matter what you buy, there will be a day when you need to repair a part. The bench grinder is no different. The only issue with repairing a bench grinder is that there are a variety of parts that can cause the same problem.
This means that you need to do a thorough inspection of your bench grinder to make sure you find the right part causing all the problems. Most of these problems are easy to fix and only call for replacing the part at fault.
These are the more common issues that arise with a bench grinder. If you have really serious issues, we recommend that you go to a power tool repair service and get expert help.
