Horizontal Band Saw Restoration - Zapins

What oil should I use? One gear is brass the worm gear is steel.

 

From the Grizzly saw manual online:

“Remove the cover on the gear box in Figure 41
and coat the gears with general purpose grease”

Denis

 

Hmm it had oil in it originally. I think some machines use oil?

 

Is that worm pin tapered to lock it in place, like a 1:48 taper for Imperial and 1:50 for metric. If so you'd have to get a taper pin reamer to finish the hole and maybe a fresh taper pin. You can tell if the worm has one side of the hole slightly wider than the other.

 

Mine had oil in it too. Quite foul stuff if I remember correctly. I cleaned and refilled with 80/90 gear oil. That's also foul stuff.lol.
I'm surprised that hardened shaft drilled so nicely. I wouldn't have thought that would work.

Pete

 

I actually think my 30-yr-old Grizz has gear oil in it. It could be that the designers decided it does not require seals to keep grease in the box vs oil. I’d bet either would work fine as long as your seals are good. Most likely just being sure SOME lube remains in there is the key.

Rather than use a solid pin to drive the worm gear, I’d suggest using a roll pin would be a lot better. Also the current pin looks to have some slop in the worm gear hole. It might be better practice to make sure the holes in the shaft and pin are the same diameter and then drive in a snug-fitting roll pin. Being hardened to spring temper it won’t fail and the snug fit will prevent it vibrating out.

Denis

 

Yeah I think I'll go with the roll pin. Or I can hammer in a piece of mild steel and flare the ends so it doesn't come out.

Do you think the type of oil makes a big difference? Or any machine/gear oil? I'm guessing I need to avoid Sulphur containing oils for the brass?

The carbide bit worked very well. The first one I used broke because I pushed too hard but second one went through easily. I read about the trick on Google and decided to try it out. Worked very well.

 

You made me do a little reading---not a bad thing. Evidently, the sulphur in EP lubes is in a relatively inactive form compared to elemental sulphur. ASTM has a test standard which evaluates reactivity with copper-contraining metals.

https://www.machinerylubrication.com/Read/28958/ep-additives-effects

"When adding EP oil to gearboxes containing yellow metals, remember to check the copper strip corrosion test (ASTM D130) to help predict if there will be any issues with compatibility of the metallurgy within these machines."

"Driven Gear Oil"
Driven Racing Oil GL-4 Gear Oil

Driven Racing Oil GL-4 conventional gear oil is designed to deliver maximum performance and protection. The formula features proven oil technology to provide application-specific performance for gear boxes, transaxles, and transmissions that call for GL-4 gear oil. Utilizing high-quality base oils, Driven GL-4 protects yellow metals and provides proper synchronization to prevent gear clashing in synchronized manual transmissions.


Learned something here. Not a bad thing...

Denis

 

Automotive manual transmissions almost always have a few parts made out of yellow metal so any type of oil intended for use in manual transmissions should be compatible with copper containing metals.

 

Reassembled part of it. Will get my chip tray back tomorrow probably.

 

You are making a fantastic job of that overhaul. It is going to be a great addition to the shop.
Mark

 

And I see the roll pin in place—-yes!

Denis

 

Roll pin or taper pin. Something easy to remove if you have to service it in the future. A rivet would make life tough in the future (the mild steel pin peened at both end is effectively a rivet).

Nice work on this saw.

 

yes roll pinned it in and cut to size.

There is a tiny amount of slop which I will have to keep an eye on. The hole through the shaft is slightly bigger than the hole through the worm gear casing, so it moves slightly. Hopefully it doesn't wiggle loose over time.

Going to keep reassembling it today and see about remaking the blade cover which is not salvageable from original piece.

The chip tray should be done today too.

 

Oil is always a better lubricant than grease. Grease can be pushed away at extreme-pressure contact points, where oil continues to flow.

 

Zap,

I don't want to be a drudge, but if it possible, I would suggest redrilling the hole in the gear and shaft so that they are the same size. I am afraid the roll pin will not tolerate a less than snug fit in both parts. I suspect redrilling the hard shaft is not something you look forward to. Ideally you would simply bore both the gear and the shaft simultaneously making a nice clean and uniform through hole and then find a roll pin that would fill the hole. BUT, you did not have an easy time drilling the shaft.

Softening the shaft end to allow redrilling could be done with a torch, but probably carries a small risk of warping the shaft.

So, I will loop back to your idea of peening a soft steel pin into the hole. If the difference in hole sizes is only a few thou, carefully peening the pin with many gentle blows can swell the pin enough to fill up the hole in both the gear and the shaft. That is one of the beauties of a well-peened rivet. In this case it would be worth looking up proper technique for rivet peening. (True confession: I have an affinity for proper rivets, though I find application for them only occasionally.)

I agree that removal of the rivet will be a little harder than driving out a roll pin. But it is very doable and, importantly, a well-peened rivet is less likely to need replacement than a poor fitting roll pin. That sloppy roll pin will also damage the hole in the shaft tending to make it oval so that future repair will be even more problematic.

Denis

 

In defense of grease I will say that it is the lube used, for example, on the drive pinion and driven gear in drills, angle grinders, automotive wheel hubs, and a great variety of other equipment. The thing that allows it to work effectively is that the gear need not be bathed in a constant pool of lube. Only a thin layer of whatever is providing protection and that layer can be renewed by simple "contamination" of the sliding surfaces with a tiny bit of lube periodically. So, yes, most of the grease gets thrown out of the actual contact area. But a film remains and is frequently renewed as the grease warms in use and vibration displaces it etc.

In this case, we do not really know if your machine was designed for oil or grease originally. But, it had oil in it when you got it. So, 99% chance it was designed for oil. I'd also vote for oil and put in a GL-4 gear oil. If it does not leak out, you are good to go.

Denis

 

On a slightly different note, if I had a 1 hp motor at 3450 rpm and connected it to a 1:2 gear reducer... that effectively makes it a 2 hp motor at 1725 rpm right?

 

It'll double your torque but not the horsepower (rate of work being done) which stays constant.
RPM = Horsepower x 5252 / Torque (foot pounds)

 

Wouldn't it be the equivalent of a 2 hp 1725 rpm motor?