Startrite Bandsaw Repair

[projectnut]

I've had a Startrite model H175W horizontal/vertical bandsaw going on 20 years. The saw was used when I purchased it with a build date of 1985. As luck would have it I no more than finished up restoring the Baileigh cold saw and the gearbox on the Startrite started leaking. It wasn't much of a leak, but enough to put a few drops of oil on the shop floor. I decided last week to disassemble a few things to see if the leak could easily be corrected. It turned out the only problem was a failed grease seal behind the band drive wheel. I was able to replace the seal and pump in a little more grease without any problems.

While I was working on it, I decided to see why the coolant pump was inoperative. In all the time I've had the machine I've never used the coolant system. The saw has always done a good job and I haven't had the mess and smell that goes along with coolant. After seeing how well the coolant system worked on the cold saw, I thought I'd see if I could resurrect the one on this saw. The problem turned out to be minor in that the only thing wrong was dried coolant preventing the impeller from turning. When the impeller wouldn't turn it kept tripping the circuit breaker.

Unfortunately, I had to disassemble the motor to remove it from the machine. What I didn't realize was that the motor was filled with oil. When I removed the end cap all the oil ran on the floor. Some research reveals it was filled with mineral oil. I'm not sure if there's any viscosity or dielectric property differences between brands of mineral oil. I would appreciate any input from you electrical geniuses on the subject. If in fact all mineral oils are pretty much the same, I can go down to the local Home Depot and buy a quart. On the other hand, if I need something special, I would appreciate knowing it before I do something stupid.

 

[markba633csi]

An oil filled motor- definitely unusual. Probably no electrical/dielectric purpose, I'm thinking maybe heat transfer or bearing lube?
What kind of bearings are in there?
-Mark

 

[projectnut]

The motor is part of a “little Giant” submersible coolant pump. I believe it’s a model 1-A but that information is no longer readable on the legend plate.

Most of the Little mGiant submersible pumps are oil filled and sealed to keep water and/or coolant out.

The bearings are miniature ball bearings.

 

[vocatexas]

Any good oil jobber should be able to get the correct dielectric oil. When I worked for Texaco we sold several different types to electric companies, but it's been too long for me to remember the names of them. It wasn't something we dealt with every day.

 

[Eddyde]

I would get a light weight, clear mineral oil. Air tool oil is usually around 10w mineral oil.

 

[projectnut]

A little more research revealed the original mineral oil was ISO 32 10W. I was able to find 4 oz bottles at McMaster. The pump is now cleaned and reinstalled in the coolant tank. It runs fine and pumps quite a volume for its size. Now that the saw is complete it will once again be the go-to machine for almost everything. I must say I'm impressed with the quality of the build and the longevity of the machine.

Now that the coolant system is functional, I'm still not sure whether or not I will use it. The saw seems to do a good job dry cutting and I'm not sure it will do any better with coolant. The one possible upside could be extended life of the blade. They now last between 2 and 3 years with almost daily use. It might be possible to stretch that life span up to another year. However, at blades being $40.00 a copy, and coolant over $60.00 a gallon it's probably not going to save much if any money. If I add in the time to clean the saw and coolant reservoir it's almost certainly a money losing scenario. At least now I have the option should I need to cut some material where coolant would be beneficial.