Hey there, I'm in the process of replacing grease zerks on my komatsu PC75uu-2 and have been trying to figure out what sizes they are in order to buy them in bulk, seemed pretty simple but I've been unable to match them up to a standard thread size at my local stores. They look like a 6mm zerk but dont actually fit. Can someone point me in the correct dirrection? Just looking for general info on if they use a standard metric thread or somthing different so I can either buy them in an assortment or say the heck with it and get them for 3 bucks apiece from komatsu. Thanks in advance!
I'm not certain, but I'm thinking they use a 1/8" British Metric Pipe Taper thread grease fitting. Those are very close to 1/8" NPT thread, but slightly larger in diameter and something like 1 thread per inch different pitch.
I've been told they're metric but the taper is different. I've been buying fittings from Komatsu ($$$) and there is a definite difference. What the truth is I don't know but I've never been able to source them anywhere. The standard metrics will kind of fit but not very well.
Beats the hell outa me, but the problem I've been finding is that many Asian and Euro machines use 1/8" BMPT grease fittings, and for some reason I can not explain, I can not find them at any local source. I'll call a supplier, "oh yeah, we have them", pick some up, and they are 1/8" NPT. You can tell because 1/8" NPT fittings take a 7/16" wrench. A 1/8" BMPT takes a 10MM wrench.
They are a British thread, it might be a British Standard Fine Thread, the Komatsu dealer knows.
If they're British pipe that explains a lot. The European countries that have been metric forever still use that pipe thread with one thread difference from ours. I've seen quite a few American plumbing fixtures attached to European pipe. They screw on far enough to seal before they jam up.
Your NPT and our BSPT are very similar. Same diameter,one is 18 threads per inch the other 19.I forget which is which.
Good to know, thanks for the info, was kind of wondering if it was somthing like that. Guess I'll be calling komatsu. Thanks again guys!
Your spot on RayF. I'm near certain those grease fittings are going to be 1/8" British Standard Pipe, also knows as 10MM grease fittings. Very similar to 1/8" National Pipe Thread, but not the same. Here's some info on the differences. http://pipeandhose.com/node/2
They are 1/8" BSP or usually called 1/8" gas thread in the U.K and a 10mm spanner size.I use a 1/8" BSP tap when cutting or repairing threads for grease nipples on Komatsu units.
Where do you buy these? Dealer only? Thanks, Greg
I get my 10mm zerks from local Rudd dealer in e'ville ,in. pt no.9481-10003
When Japan lost in WWII part of the surrender treaty required them to dispose of all their engineering standards and adopt those of Europe of the United States. Japan chose the European standards so for many years all plumbing fixtures were done in British Standard. Here is a "secret", if you run a 1/8" NPT tap down the hole you can use the American standard and buy your grease fittings anywhere. You will have the added benefit of a larger nipple for your grease gun tip to grab onto and less wasted grease blowing out the side of the fitting. In other words don't waste your money on the overpriced fittings from the Komatsu dealer or after market fitting supplier. A standard fitting from Napa costs about a tenth as much and lasts much longer.