Help ID vintage right angle milling head

chippinchunks · Jan 30, 2019

Hello all

I have a small benchmaster vertical mill that I use for light work. It works well for its small size but the milling head starts to make noise if I don't keep it filled with grease. I use high temp synthetic bearing grease because that's what the previous owner had been using. I grease the mill head through a zerk fitting on the top of the support shaft to lube it up. Usually after a couple pumps the rattling sound from the mill head goes away but after the mill head heats up it tends to throw the grease out through the bottom of the spindle. Soon after it starts making noise again. I was hoping to find some info on this milling head so I can determine the proper way to service and lubricate it but endless online searches have yielded nothing. I provided some pictures below of the milling head. It uses 1A or 3C collets (both seem to work fine) the only numbers I can see on the mill head are SG-135 other than that I'm not really sure how to ID this thing. I know it's not the original milling head for a benchmaster mill but this is how I bought it. Any help would be greatly appreciated. Thank you

Martin
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wdTom · Jan 30, 2019

Is it possible it is just a right angle gear box someone made into a milling head? To me it looks like it might be. Also it doesn't look too hard to take apart and explore. Find out if it has a bad seal, or what is making the noise. The end cover looks like it has instructions for adjustment.

kitno455 · Jan 30, 2019

Says 'Elevation clutch' right on it- sounds like a part related to aiming something? Have you tried tightening the clutch screw?

allan

chippinchunks · Jan 30, 2019

Thanks for the input guys. I suppose it could be a gearbox of somekind. I haven't tried adjusting the clutch yet but i suppose I can try that 1st. If that doesn't work I'll tear it apart & see what I can do to keep the grease from coming out.

Thanks again
Martin

Frank R · Jan 31, 2019

Just curious, how is the head attached to the overarm? Is it welded on?

Is the overarm custom too? From the pulley on the backside it looks like there is a driveshaft through the center. That is a pretty sophisticated build for a small mill.

jhruska · Jan 31, 2019

Excess heat is caused by an overabundance of grease. Churning is the result as the grease is mixed by the moving parts.
The blob of will hold the heat. Look for an high pressure grease like the old style wheel bearing grease that has sticky hairy threads. Apply that to the gears.
If brass or bronze is present avoid the EP grease.
John

chippinchunks · Jan 31, 2019

Frank R said:
Just curious, how is the head attached to the overarm? Is it welded on? Is the overarm custom too? From the pulley on the backside it looks like there is a driveshaft through the center. That is a pretty sophisticated build for a small mill.

Yes, I believe the entire overarm assembly is custom. The mounting flange was welded onto the overarm support & turned down on a lathe. The milling head is bolted to the flange. It's not pretty by any means but it works well for its small size. I trammed the head & it was off .004 over 4" on the Y axis. I was expecting it to be a lot more than that

Martin

chippinchunks · Jan 31, 2019

jhruska said:
Excess heat is caused by an overabundance of grease. Churning is the result as the grease is mixed by the moving parts.
The blob of will hold the heat. Look for an high pressure grease like the old style wheel bearing grease that has sticky hairy threads. Apply that to the gears.
If brass or bronze is present avoid the EP grease.
John

Thanks John. That's definitely what's happening here with the grease. I had a feeling I wasn't using the right lube. I initially tried spindle oil but the grease is so packed in I could only get a few drops through the zerk. The rest of the oil would overflow out the top. So if there are ball bearings or bronze bushings in the over arm shaft spindle oil? Gear box if metal gears old school stringy gear grease?

Martin

jhruska · Feb 1, 2019

Martin,
Grease by simple definition is oil suspended in a medium.
Choose an electric motor bearing grease for the bushings/bearings or use the synthetic. Generally it will stay in place for a period of time depending on hours of use and temperature. Set your maintenance interval by this.
Gears need something that will adhere as a thin film. This should be different than the bushing/bearing grease. Some bushings are
sintered bronze with oil in the pores...self oiling. This will be hard to determine after long hours of service. The top cover and the lower casting are large enough for bearings and they could be shielded and may contain grease.
If it is taken apart see if the zerk fitting is positioned to lay grease on the gear teeth. If yes then a proper way to grease the gears is to apply
squirts of grease when in a lowest rpm.
Summing up; it is okay to use two types of grease within the same housing. Bearings/bushings can have a moderate one time application and gears will get just enough at low speed to coat the teeth. Some grease will chemically react with another causing a breakdown of the medium.
Using synthetic in a modest quantity should not present a problem.
This unit is not likely to have run the gears in an oil bath. Fines generated by gear wear would migrate into the bearings/bushings. If taken apart look for oil seals.
John

chippinchunks · Feb 1, 2019

jhruska said:
Martin,
Grease by simple definition is oil suspended in a medium.
Choose an electric motor bearing grease for the bushings/bearings or use the synthetic. Generally it will stay in place for a period of time depending on hours of use and temperature. Set your maintenance interval by this.
Gears need something that will adhere as a thin film. This should be different than the bushing/bearing grease. Some bushings are
sintered bronze with oil in the pores...self oiling. This will be hard to determine after long hours of service. The top cover and the lower casting are large enough for bearings and they could be shielded and may contain grease.
If it is taken apart see if the zerk fitting is positioned to lay grease on the gear teeth. If yes then a proper way to grease the gears is to apply
squirts of grease when in a lowest rpm.
Summing up; it is okay to use two types of grease within the same housing. Bearings/bushings can have a moderate one time application and gears will get just enough at low speed to coat the teeth. Some grease will chemically react with another causing a breakdown of the medium.
Using synthetic in a modest quantity should not present a problem.
This unit is not likely to have run the gears in an oil bath. Fines generated by gear wear would migrate into the bearings/bushings. If taken apart look for oil seals.
John

Lots of good information here. Thanks again
Martin

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Help ID vintage right angle milling head

chippinchunks

Aluminum

wdTom

Aluminum

kitno455

Titanium

chippinchunks

Aluminum

Frank R

Stainless

jhruska

Titanium

chippinchunks

Aluminum

chippinchunks

Aluminum

jhruska

Titanium

chippinchunks

Aluminum

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