bandsawing steel stock - what am I doing wrong?

Jim Mass said:
OK, thanks to all again.

Looks like there's agreement on the cause - the high speed.
Jim, thanks for pointing out the 'inside out' blade = upside-down teeth possibility. In future, I won't take that for granted, maybe prevent another ruined blade.
So, where to go from here? I'm space-limited, would really like to have a one-size-fits-all bandsaw, and I really like this Jet (except for it being wrong for steel - right now).
Maybe a few possible routes:
1) permanent speed reduction?
- (like Fabrickator's suggestion) jackshaft type; like he said, probably get a 3:1 reduction going that route), and use existing motor; maybe in the neighborhood of $150-$200 cost if I did one myself (bearings, sprockets, shafts, plates, a bit of chain, new v-belt). Seems like it's still higher than ideal speed by a factor of 2 or more.
- speed reducer; can get bigger reduction, but may not necessarily be able to use same motor; probably custom new motor mount. Has anyone done this? War stories?
2) Change to a variable speed drive? This thought is very compelling, offering possibility of best of both worlds (unless the devil is in the details).
- what are pros and cons? has anyone done this for a reasonable cost? (My current motor is 1HP, 110V; I currently only have 110V available)
3) Get rid of this saw, and get a correct one for cutting steel (at maybe 10X or more of my current investment)

Thoughts appreciated.

If this discussion is beating dead horses, would appreciate if you point me to the carcasses.

Thanks again, and hope I can help you at some point.

Jim
Click to expand...

There are some threads here about VFD's and lathe or mill motors.... Might want to do some reading. This would not be the cheapest approach.

Here is a thought: Is there a way to change the pulleys to get a wider range of speeds... AND
Go to a variable speed motor, or a 3PH motor and a VFD?

Just things to consider.

In the end... a new (or pre-owned) combo (horiz and vert) bandsaw with wider speed range (or variable speed)... might be the better thing to consider.
 
Harbor Freight 5x6 metal bandsaw, $249.99. Will they let you use the 20% off coupon as well?
Find a 3 phase 1hp motor with 110v VFD. Find a 1hp DC motor and controller for 110v.
With either of these I would try to adjust pulley size as well so you can increase motor rpm some and get into the power range of the motor while running the blade slower.
Dave
 
Thanks Guys,

Dave, I was actually thinking something similar - got the idea from Hoss, the famous bf20 milling machine hacker...

You think this might have some possibility?
http://www.ebay.com/itm/261650838569?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

There are tons of these motors and controllers available both new and used for reasonable cost - looks like some of them have flywheels.

And, what needs to be known about the power range of a motor/controller like this? Are there pertinent torque/speed curves I should consult?

- Jim

P.S. Harbor Freight for big power tools, hmm. I know they come from essentially the same place as the Grizzly stuff, but looks like Grizzly takes the steps to assure they receive and distribute the good stuff.
 
I rebuilt a HF wood band saw. I used a 60:1 reduction unit to slow it down. It cuts like butter now.

"Billy G"
 
Jim Mass said:
Thanks Guys,

Dave, I was actually thinking something similar - got the idea from Hoss, the famous bf20 milling machine hacker...

You think this might have some possibility?
http://www.ebay.com/itm/261650838569?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

- Jim

P.S. Harbor Freight for big power tools, hmm. I know they come from essentially the same place as the Grizzly stuff, but looks like Grizzly takes the steps to assure they receive and distribute the good stuff.
Click to expand...

That is a good option I think. I've seen them used on wood lathes and small mills with success.I too have trouble with HF power tools. I own a Grizzly lathe and mill and they are far, far better than anything I've got from HF. I would go as far as saying my Grizzly are as good as the many Jet tools I own.

Dave
 
dave2176 said:
That is a good option I think. I've seen them used on wood lathes and small mills with success.I too have trouble with HF power tools. I own a Grizzly lathe and mill and they are far, far better than anything I've got from HF. I would go as far as saying my Grizzly are as good as the many Jet tools I own.

Dave
Click to expand...

The guys at the airport hanger have a saying about HF:

If it is a HF product, and has bearings in it... proceed with caution. :nervous:

Seriously... HF has some good stuff... and they have some junk.

Probably a good idea to carefully inspect anything before buying it.
 
Fabrickator said:
As was said, its a wood saw and youll have to reduce the speed a lot. I put a triple reduction on mime (jackshaft) and now it cuts steel great. I have the formula, pulley sizes, pics, but not right now on tablet.
Click to expand...

I would love to see your setup for the triple speed reduction.


Jamie
 
Consider a riding mower transmission. Here is a three speed (probably plus reverse) which appears to have only one output - to a sprocket.

Look at this on eBay:

http://pages.ebay.com/link/?nav=item.view&alt=web&id=181579905817

Foote 3 Speed Transmission H Pattern Pat #D208,213

There are also four- and five-speed units, and hydrostatic designs which vary from forward to reverse with a single lever.

Have seen automotive transmissions used to increase speed selections for old lathes. Have seen hydrostatic transmission used in a 7-1/2" gauge locomotive.

If this approach seems appealing, cultivate someone who repairs mowers for a living - preferably from a well equipped home shop. Might get an advantageous buy on what you need and certainly could learn a lot about hooking things up.
 
Hey Guys,

I'm the OP on this, posting with what I finally did for the solution.

After watching Ebay for a couple weeks, I ended up getting an new old stock Emerson 1HP 90VDC motor and a used Dayton DC variable frequency drive, and replaced the motor.
Cost me $150 (almost exactly), a couple gallons of gas to pick the components up, and about 4 hours to put them in. Things didn't fit perfectly, I had to make transition brackets because the motor length was different from original, etc.
I also remoted the VFD power-on lamp and the speed pot to the front panel right below the on-off switch, while the rest of the VFD enclosure is mounted inside the enclosed under-saw platform.
Had a big scare when I cut my first steel at ~250FPM, and the blade & moter just stopped under the load. Then I discovered that the jumper inside the VFD was set for a 1/8 HP motor. Re-jumpered for 1HP, and it has plenty of torque over the entire speed range. My test piece was 1/2" 1020 steel, no problem.
It really is so nice to just turn a pot and get the ideal speed for the material you're cutting. I'm glad I did it!

Again, thanks for all your help.

BTW, that last idea with the riding mower transmission looked interesting - probably need to have plenty of room to situate it with the motor though.

- Jim
 
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