Hot and dry 4 1/2 grinder head

[Tgrasher]

I like to use a 4 1/2 grinder with a wire brush to clean metal with. Usually there are pits in the metal that a sander doesn't get to. Over time I've worn out cheaper grinders so this last time I went with a Milwaukee. As with the others, the head on this grinder slings the internal grease every place but where it's needed. If I add more grease, it oozes out around the shaft, then slings on the metal I'm going to paint. The head on this grinder heats up and gets so hot you can't touch it. The grease I'm using is a hi- temp bearing and it's not doing the job. The first time I took this head apart the factory grease was really thick but it had slung to the side and the gears were dry. Anyone know a solution to this?

 

[caterpillar guy]

Don't push so hard on the grinder to get rust off. Let the grinder do the work.

 

[Geo-TH,In]

I clean my head and use a thin coat of white lube.
Works for me.
I also have 3 right angle corded grinders. So if one gets hot, I use the other. I like to have a cut off blade on one, a grindstone on the other and a wire brush on the third one.
Also have a cordless right angle to take on the road too...
Can't have too many right angle grinders..

 

[Steve@Advance]

I can't recommend anything you haven't already tried. Maybe put in a grease fitting so it can be very sparingly greased as needed without slinging.

Milwaukee used to be great grinders, now they are hecho en China.

Last grinder I bought was a Makita, so far so good, but the new ones could be a different story.

 

[GarryinNC]

Try a Metabo brand grinder. Have had good results with them,

 

[RobCons]

I use Makita. Keep 4 of them on the welding table. Each has a different wheel, a stone, cut off wheel, flapper disc, and wire wheel. Dont have any problems with them.

 

[Janicholson]

Replace the seal (maybe a better designed one) use 0 grade grease (thinner) rest more between uses. (find an old Sioux or Mall) or buy a Metabo. Jim
some

 

[bmack95hd]

We sold Hitachi, Bosch, DeWalt, Milwaukee, Makita and Metabo grinders. Most 4 1/2 grinders are considered disposable, not worth sending in for repair. Hitachi and Metabo were our best selling units and now they have merged. Try one you wont be disappointed.

 

[Tgrasher]

I've ordered a Metabo to give one a try, probably should have ordered two or three. Will try the other suggestions for the Milwaukee but I can't slow down, too much to do, and not enough time. I don't think this is the way retirement is supposed to be.

 

[BarnyardEngineering]

What you're missing is the grease and the heat work together. Heat melts the grease, and it flows into the gears, keeping them lubricated.

Notice in your pictures that the gears are hardly dry. They don't need to be gobbed with grease to be properly lubricated, only wet with the oils that the grease releases when heated.

This is the "corn head grease" principle.

 

[ss55]

Looks like cornhead grease what is already in it, leave it as-is.

Not all power hand tools are built to run 100 percent duty cycle for very long. For the longest possible tool life, consider alternating between two grinders to give each one a chance to cool down. Run one for 5 to 10 minutes then switch to the other.

 

[1948CaseVAI]

I abuse my grinders awful so I just buy them 6 at a time at Harbor Freight and throw them away when they give me grief. From what you wrote it sounds like you abuse yours as well. I cannot imagine taking the time to take a grinder apart to try to fix something.

 

[Gene Davis (Ga.)]

The 4 1/2 grinder gearboxes are not supposed to be packed full of grease. That will make them run hot and really sap the power also. I have a Sears,(don't know what company made it) that is ~30 years old and I take the gear case head apart about every 3 years, clean it out and repack it with a small amount of lubriplate white grease and it still performs well. I also buy the cheap $19.00 grinders from Walmart and use them for the really heavy and dirty grinding as they are disposable for that price in my book.