Probably pushing the limits

[DPittman]

I'm going to attempt to cut a 8" piece of aluminum with my 7x12 band saw. Only because the piece is short is why the normally 7" max clearance of the bow of the saw should clear. I want to cut off only 1" of material but I have to lop off 2" initially to allow that clearance.

 

[DPittman]

25 minutes to cut the first slab! I am running a fine blade (maybe a 10/14?) and I know a course blade would be much faster. The first cut I was running the saw at 178 fpm and then for the second cut I ran it at 260 fpm and that cut down the cutting time to 20 minutes. I have a notion that with a course blade the cut finish might be better as I think swarf was not being drug out as well as it could have been resulting in a rougher finish.

 

[Brent H]

Impressive cut!

 

[CalgaryPT]

Nothin' wrong with that job on a 7x12.

 

[Mcgyver]

looks like a nice square cut - you've got that machine set up well!

 

[DPittman]

Yes it cuts amazingly square. I've been really pleased with the machine considering what it cost.

I have read about the worm gears in these saws going bad so I pulled the gearbox cover to take a look and mine appears fine. There didn't appear to be ANY metal filing in the oil whatsoever that I could see but there was sludge at the bottom of the case that appeared to be maybe old gasket material? Anyhow I cut a new gasket and filled it back up with fresh gear oil.

 

[CalgaryPT]

You can always do the rare earth magnet trick, where you imbed one in the bottom of the crankcase to trap shavings. Just be careful to secure it properly.

But yours looks terrific.

 

[Susquatch]

You can always do the rare earth magnet trick, where you imbed one in the bottom of the crankcase to trap shavings. Just be careful to secure it properly.

But yours looks terrific.

Looks like the main gear is brass. If so, it will be the one to wear and a magnet won't help.

Good news is that it's relatively easy to make a replacement.

If the main failure mode is wear, I'd put a drain hole in and change the oil regularly with a good synthetic.

 

[YYCHM]

If the main failure mode is wear, I'd put a drain hole in and change the oil regularly with a good synthetic.

What oil do you suggest? I asked this previously and it generated a big debate that never answered my question.

 

[PeterT]

If I understand the saw limitation correctly where the C frame is interfering with the log on the left hand side. What about a simple wood plank fixture where the log is on RHS. The log is clamped to an upright fence, then you can slice cut off whatever width you require.

 

[DPittman]

If I understand the saw limitation correctly where the C frame is interfering with the log on the left hand side. What about a simple wood plank fixture where the log is on RHS. The log is clamped to an upright fence, then you can slice cut off whatever width you require.

View attachment 18179

Yup I believe that would work fine if you had a sturdy enough support on the right had side. I've made myself a little angle iron table/support for the right hand side I use when I'm cutting pieces too short to clamp safely/effectively in the saw vice.

 

[Susquatch]

Looks like the main gear is brass. If so, it will be the one to wear and a magnet won't help.

Good news is that it's relatively easy to make a replacement.

If the main failure mode is wear, I'd put a drain hole in and change the oil regularly with a good synthetic.

I was not a part of that debate so I'll venture forth where wise men fear to go.

If your manual specifies an oil, use a synthetic version of that. If not a good high quality synthetic 80 weight gear oil should work.

Bring on the debate!

 

[DPittman]

What oil do you suggest? I asked this previously and it generated a big debate that never answered my question.

I didn't even bother trying to figure out what people considered was the "right" oil for the gearbox. I put in 80w90 gear oil partly because I had it on hand and also because I felt it proved adequate in higher speed and higher torque applications over many years.

 

[CalgaryPT]

Looks like the main gear is brass. If so, it will be the one to wear and a magnet won't help.

Good news is that it's relatively easy to make a replacement.

If the main failure mode is wear, I'd put a drain hole in and change the oil regularly with a good synthetic.

True enough. I'll have to check my King 7x12 Swivel; I don't think mine is brass. I know when I replaced the bearing on my buddy's 4x6 years ago his was brass, and was badly imbedded with cast dust and small steel particulate. When I ordered the new parts from King in Quebec (they were great to deal with), the parts guy told me the embedded stuff was from the casting and there were two ways it gets in there. One is from original casting process and the drilling process for the bearing itself. They other was as the bearing wears it tends to wobble and this causes casting shavings and fine stuff from the bearing race to make its way into the crankcase. The larger saws have two seals—one on the inside and one on the outside of the gearbox. But none of the ones I have seen ever had more than one seal (if that).

Especially with the Chinese machines, I think it is best to change the oil soon after purchase. That stuff is like drywall dust in a new furnace—it starts the damage prematurely.

 

[Mcgyver]

What oil do you suggest? I asked this previously and it generated a big debate that never answered my question.

Odds are the gear is bronze, or at least should be and don't discount bronze in the wear arena. It can wear better than a mating iron or steel gear. The thing to be aware of, if you have a copper based alloy in the transmission like this(this includes most dividing heads!) is that EP addatives used in lots of oils will have sulfur which will react and eat away at the the copper. I can't give a non sulfur recommendation offhand, but imo it would be worth a call to a lubrication dealer like Commercial Oil. No idea how rapid the damage is but you'd hate to find out from experience that was rather quick.

 

[YYCHM]

Odds are the gear is bronze, or at least should be and don't discount bronze in the wear arena. It can wear better than a mating iron or steel gear. The thing to be aware of, if you have a copper based alloy in the transmission like this(this includes most dividing heads!) is that EP addatives used in lots of oils will have sulfur which will react and eat away at the the copper. I can't give a non sulfur recommendation offhand, but imo it would be worth a call to a lubrication dealer like Commercial Oil. No idea how rapid the damage is but you'd hate to find out from experience that was rather quick.

And this was the debate that occurred.

 

[DPittman]

Odds are the gear is bronze, or at least should be and don't discount bronze in the wear arena. It can wear better than a mating iron or steel gear. The thing to be aware of, if you have a copper based alloy in the transmission like this(this includes most dividing heads!) is that EP addatives used in lots of oils will have sulfur which will react and eat away at the the copper. I can't give a non sulfur recommendation offhand, but imo it would be worth a call to a lubrication dealer like Commercial Oil. No idea how rapid the damage is but you'd hate to find out from experience that was rather quick.

And with that information I'm going to guess that a synthetic gear oil is a better choice. I'll report back on my findings of using regular gear oil in 5-8 years when I will likely change the gearbox oil again. Unless I have catastrophic failure with the gears before that time!

 

[Mcgyver]

And with that information I'm going to guess that a synthetic gear oil is a better choice. I'll report back on my findings of using regular gear oil in 5-8 years when I will likely change the gearbox oil again. Unless I have catastrophic failure with the gears before that time!

I don't think that would matter. afaik alot or most synthetic oils are also going to have EP additives....I think its a simple matter of asking someone at an oil store what oil you can buy that doesn't have a sulpher based EP additive.

And this was the debate that occurred.

lol, so am I opening old wounds? sorry, don't mean to. I wouldn't have thought the brozne not liking supher EP thing is very contentious, pretty consistent reads on industry web sites about it. I guess what might be up for grabs is how fast/how severe the effect is (or least I don't know) ....but who wants to find out the hard way?

 

[DPittman]

.but who wants to find out the hard way?

Me me I'm going to for the sake of science and for the love of my fellow metal working hobbyists!

 

[Brent H]

Some Light reading:

Monitoring Active Sulfur in EP Gear Oils

Extreme pressure (EP) gear oils are used to minimize wear and scuffing in automotive and industrial applications under high load conditions, especially where high peak or shock loads are...

www.machinerylubrication.com

The Right Way to Lubricate Worm Gears

Of all the different types of gear configurations, worm gear systems are considered some of the most problematic because they present unique lubrication challenges due to their distinct desi…

www.machinerylubrication.com

Highlight: "EP oils are still commonly used in worm drive applications where they are formulated with yellow metal compatibility. However, both compounded oils and EP gear oils have a working temperature limitation of approximately 80 degrees C before oxidation rates rapidly increase, resulting in acidic products that can attack cupric worm wheel materials."

It would be very wild to have you bandsaw heating up to 80*C at the worm drive

I think you are safe with a good quality oil and maintain a good level of lubrication.