Our Van Norman Flywheel Grinders are one of the most profitable machines you could own. They are not difficult to operate or maintain and tend to last a long time without the need for service if you do the few things that need to be done to maintain them. With a little instruction just about anyone in your shop can grind a flywheel successfully. The setup is easy and the job itself goes very fast. Typically, you should be able to get about $100 per hour if you have steady work for your machine. Even if you don't have enough in-house work for it, you can likely get some outside jobs from other shops who don't have a flywheel grinder. There are also optional accessories available that allow you to do more than just grind flywheels. It's becoming more common for Heavy Duty Trucks to have disc brakes with rotors that can be ground on our Van Norman Flywheel grinders with our Optional HD Truck Rotor Kit.
Here’s a quick overview of how to set up and use your flywheel grinder.
Not all stones are created equal. Make sure you’re using the correct stone for the material you are grinding – cast steel, billet steel or cast iron. If you aren't sure, you can ask your Irontite Sales Associate to help you determine the best stone for the type of material you will be grinding. There are also CBN wheels that you can use. These are much more expensive, but they also last about 10 times longer and some technicians feel they provide a better cut. CBN wheels are not dressed by removing material like traditional grinding stones. Instead, there is a cleaning stick that is used to remove any stuck-on material from the cutting surface of the CBN Wheel.
General Purpose Stone CBN Wheel
Follow our guidelines found in this section of the website for the correct dressing technique. The article was originally written for valve seat grinding stones, but the dressing principles apply to any grinding stone. You can view this Article here. The Van Norman Flywheel Grinders typically come with a Star Wheel dresser, but there is also a Diamond Dresser available. And, of course, if you are using a CBN wheel, then you do NOT want to use either of these dressing methods. Your dressing technique will influence how the stone reacts against the flywheel material. Basically, a quick pass dress will open the pores of the stone and deliver a rougher finish but cut more aggressively, and a more slow pass will close up the pores delivering a finer finish. You should vary your technique to determine which method is best suited for the flywheel you are grinding.
Be sure to check your coolant reservoir and skim the tramp oils on a regular basis, especially during the heat of summer. Your coolant will experience some evaporation. A good way to combat loss of coolant is to mix the coolant in a separate 5-gallon container with a lid so that as you need additional coolant it will already be mixed and ready to pour in. This will also prevent altering the coolant mix ratio that can happen when you add a little more water here and there and then maybe a splash of concentrate and before you know it your coolant is too watery and things rust or it's too concentrated and your grinder isn't cutting like it should.
The coolant you use and how it's mixed can greatly affect the effectiveness of your grinder. Irontite has spent considerable time researching and experimenting with all different kinds of grinding coolant concentrates at differing mix ratios to come up with our recommended coolant concentrate product and the best mix ratio for most operations. As always, if you have questions, your Irontite Sales Associates are knowledgable about our products and can help you make an informed choice. They are at 800-553-5953 during regular business hours.
Ideally, you would just have a schedule for changing your coolant, but every shop is different and some weeks the grinder is busy while others it's not, so here are 3 ways you can tell if your coolant needs to be changed:
A great tip/trick is to get a powerful magnet (they have gotten inexpensive in recent years if you shop for one), something about the size of a drink coaster or a little smaller and place it in your coolant reservoir on the bottom as far away from the pump as you can. This will attract the metal shavings and prevent them from flowing back up to the work site. Another idea is to create your own larger reservoir with a sludge trap of some kind to continuously filter the coolant.
Be sure to inform everyone who uses the machine to never use any other chemicals on parts that are on or over the machining surface. Using something like rust preventitive on a part still attached to the grinding table can contaminate the coolant in short order. So it's best to just have a rule that you always remove any items from the machine and never use anything other than coolant while at the grinder.
Remove any dowel pins prior to mounting the work piece using a dowel pin puller. Be sure to keep track of the dowel pins and return them to your customer. When mounting, use the crankshaft-mounting flange as your reference. It's important to clean and deburr the flange and table surface before mounting. Select the appropriate flange adaptor and a centering cone. Tighten the centering cone bolt to secure the assembly to the table. Insure there is no movement and rotate the table to be sure the grinding wheel is not going to contact anything that it should not. When doing a stepped flywheel, keep in mind that the torque of the grinding motor can make the stone move slightly and you want to insure that the stone will not bump up against the wall of a step. This could cause internal cracking in a stone that will lead to the stone breaking aggressively.
There are also many optional mounting kits to help you mount all different kinds of flywheels and other types of materal. Here are several to choose from.
Hand feed the grinding wheel so that it almost touches the work piece. Put on your safety face shield and position the machine’s grinding wheel safety shield and the coolant shroud protective shield. Turn on the coolant, then the table, then the grinding motor. Manually feed the stone into contact with the work piece. You will know the stone is about to touch when the coolant on the back side of the stone begins to foam slightly. Now feed approximately .001 per revolution of the work piece. A constant spark pattern is necessary for efficient grinding. This will also cause the stone to break down and keep cutting more freely as well as keeping the stone from loading up. There will be times that you will need to stop grinding and redress the stone. If you are using a CBN wheel and it's making a lot of noise (singing) this is typically a lack of necessary downward pressure. CBN wheels require fairly aggressive cutting pressure. Or it could be dirty coolant or the CBN wheel needing to be cleaned with a CBN Dressing Stick. Continue grinding until you obtain both the finish and specification required for the flywheel.
If you have the auto-feed option on your grinding machine, you can set the depth of cut you want and use the auto feed rate knob to adjust how aggressive the cut will be.
Most manual machines will grind the average flywheel in about 10 to 15 minutes. Larger diesel type flywheels will take longer but you can charge more for those. The average labor charge for a flat flywheel is about $35 to $45. The labor charge for larger diesel flywheels averages $65 to $125
It's critical the flywheel grinder is level for proper operation. This is because the table actually floats on a bath of special lubricant called Table Lube. If the table is not level, then it can leak table lube and/or set up an unwanted wear pattern on the under side of the table. Eventually this can cause serious problems with the machine's operation and obtaining good flat grinds. Always keep the site jar located in the back right corner of the machine filled with table lube. This keeps the level under the table up and also feeds the lubricating wick in the neck of the grinder column. There is also a dip stick for checking your table lube, but, in most cases, if you keep your site glass jar filled you won't need to use the dip stick.
Grinding is a dirty business. It makes your grinder dirty. However, you can extend the grinder’s life and profitability by wiping down the inside and outside after every job. A coat of wax for any painted metal surface will go that extra mile. The wax will make the wipe down go much easier too. The inside of the coolant shroud also needs to be cleaned and waxed to prevent crud build up. If you don't wipe after every job, the build up of all the stuff splashing around will attach and harden making it extremely difficult to ever get off and will also hinder a wipe-down by catching your cloth.
Use a deburring stone to knock down any dings or dents that occur on the grinding table when mounting flywheels. This little procedure will increase the accuracy of your flywheel set-up. Inspect all your tooling and adapter rings before using. You are cleaning them anyway, why not pay attention to them and see if you have any marks that could introduce problems. If so, get them replaced right away.
Use a wire brush on the threads of your hold-down bolts so they don’t carry debris into the threads of your center-mounting hole. It’s also a good idea to periodically replace the center bolt hole thread. Our EZ-Lok replacements make it quick and easy to keep your mounting threads like new. These come with locktite red on them so you may need to use a little heat to get them free from the table. But changing them on a regular basis will keep your table and its spindle in good shape for many, many years. Organize your tool board so you can quickly find the necessary tooling for mounting the next flywheel.
Always double check your instruction and parts manual to be sure you use the recommended lubricants for your machine.
Open the back of your machine and find the leadscrew. The leadscrew needs to be clean and well lubricated. It’s always best to use the leadscrew Lube specified in the owners manual. There should be a leadscrew nut that the leadscrew goes through. This nut also needs to be lubricated and has an adjustment procedure to keep your machine from having "head drop". The owners manual gives you step-by-step instructions for this. It's a good practice to run your grinder column all the way to the top and all the way down at least once a week. This is to help keep the leadscrew lube distributed over the entire leadscrew. Over time, most operation takes place in the same small area of the leadscrew forcing the lube away. Running the head up and down redistributes the lube.
The grinding head locking system only needs to be adjusted if after locking you can move the head. Over time, the head may become difficult to move from side to side. After you insure that this problem is not because the lock is engaged, there are 2 grease zerks on the opposite side of the column where you can apply regular automotive grease to lube the column top.
Also, check to make sure the grinding head tilt is what the manufacturer designates and adjust accordingly. Inspect your dresser. Some machines have a star dresser and others have a diamond. Make sure the star is rotating and spins freely. If it doesn’t, it’s time to replace it. For machines that have a diamond, make sure it’s sharp and periodically rotated to insure even wear. Always replace if in doubt.
It’s a good idea to use a dial indicator when determining how much material is being removed. The leadscrews are very accurate, however, they are no replacement for actual measurement of how much of the stone wore away during the grinding process. This is even more critical when you are working on a stepped type flywheel. You must insure you remove the exact amount of material from the pressure plate surface as you do for the clutch disc surface to insure the original geometry stays intact.
Taking care of your flywheel grinder will allow it to make money for you for many years. And if and when you do decide to upgrade or replace it for a new machine, it will have a higher resale value.
Remember, if you have more questions, contact Irontite Products Inc at 800-553-5953