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View Full Version : Thoughts on bandsaws.



Gary Westfall
08-17-2001, 06:09 PM
Understand what you mean about having to buy mill-run lengths. Same thing here. I can get them to run off pieces cut to length for my application, but it costs considerably more than my few minutes to stack the material in the saw and cut them to length. Unless we are talking something like 5000-piece quantities. Then it makes sense to consider pre-cut stock. I just ordered 5 each 12-foot sticks of 6061-T6 in 3-inch by 5-inch rectangular bar - they wanted $2.98 a cut to cut it into 9-1/4 inch long brick. Needless to say - I got sticks (of course they weight a bloody ton .....).

I have one of the Roll-In saws - it is a vertical bandsaw that "rolls" down a slight incline to saw through material on the table. It has been an excellent performer so far. Maybe someday I will get an automatic saw (not anytime soon though).

John Stevenson
10-01-2004, 06:41 PM
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[This message has been edited by John Stevenson (edited 08-17-2001).]

Derek13
10-01-2004, 07:21 PM
To me it would just seem like it's less safe... (ie chips would be comming off AT you instead of AWAY from you... i know it's a bandsaw, but still there's the possibility)... and it's running against the moveable jaw, not the fixed jaw... which in my understanding you usually want the force of your cutting/milling etc, to go towards you FIXED jaw.

zl1byz
10-01-2004, 07:32 PM
Hell John I beleive the water swirls in the oposite direction over there too. http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

Interesting all the band saws I have used run as you said down into the fixed vice jaw. They must be older ones. Thinking about it though a lot of hacksaws run the way you sugest, but they need good feed control. I wonder if the same would be true with band saws? Perhaps the smaller ones that rely on gravity would have trouble in the horizontal position too.

ibewgypsie
10-01-2004, 07:35 PM
I got a buddy who has a harbor freight saw out in the weather, rusty.. Same blade that came on the saw, over two years old. About once in two or three months he cuts something with it. It should not work, the saw, the motor, the blade.

I never had a saw blade rust that was worth a flip, throwed them away after they turn red.

Sometimes you just get a good blade.

------------------
David Cofer, Of:
Tunnel Hill, North Georgia

John Stevenson
10-01-2004, 07:50 PM
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[This message has been edited by John Stevenson (edited 08-17-2001).]

wierdscience
10-01-2004, 08:04 PM
One reason could be that using the old method the driving contact on the blade is 1/4 of the circumfrence(under load that is)where the newer method has the drive wheel making 1/2 contact.

Also wouldn't the driving load be cut in half since the tracking wheel is now acting as sheave instead of a simple overhung load?

[This message has been edited by wierdscience (edited 10-01-2004).]

zl1byz
10-01-2004, 08:12 PM
There's no doubt your on to something John. Trying to picture the dymanics of it. Could be something the same as climb milling on a mill, certinaly has advantages including tool life, but the machine needs to be capable or big disastor.

zl1byz
10-01-2004, 08:30 PM
<font face="Verdana, Arial" size="2">Originally posted by John Stevenson:
During my time at this game I have noticed that the horizontal bandsaws usually had the blade running down to the fixed vise jaw i.e. anti clock looking fro the vise side.

John S.</font>

John! Do your clocks go the other way over there too? http://bbs.homeshopmachinist.net//confused.gif

John Stevenson
10-01-2004, 08:41 PM
Standing to the right of the machine looking at it the blade comes off the jockey wheel, thru the work onto the drive wheel and over the top back to the jockey, that's anti clock in my book or does British Summer Time run different to Pacific Standard ?? http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

JRouche
10-01-2004, 09:15 PM
<font face="Verdana, Arial" size="2">Originally posted by John Stevenson:
Standing to the right of the machine looking at it the blade comes off the jockey wheel, thru the work onto the drive wheel and over the top back to the jockey, that's anti clock in my book or does British Summer Time run different to Pacific Standard ?? http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif</font>

All the saws I have seen run that way.

Standing on the right side (drops side) the blade runs counter clockwise off the idler, through the rollers, past the moveable vise jaw over the work, past the fixed jaw, across the other set of rollers to the drive wheel then back around fer another turn. JRouche

JCHannum
10-01-2004, 09:32 PM
I don't quite see the advantage, but I think John is saying the older saw's blades run toward the hinge, the newer ones run away from the hinge.
Merely reversing the motor would push the blade rather than pull it. It seems to me this would be harder on the blade. Cause unnatural flexing??? Can't argue with success.

BillH
10-01-2004, 10:17 PM
I thought saw blades were designed to only run in one direction?

wierdscience
10-01-2004, 11:13 PM
<font face="Verdana, Arial" size="2">Originally posted by BillH:
I thought saw blades were designed to only run in one direction?</font>

So do some of my customers,till I turn the blade inside out for them http://bbs.homeshopmachinist.net//biggrin.gif

My favorite is when they bring the new blade I just welded for them back saying it won't cut,thats when I ask them if they checked to see that the teeth were headed into the cut.100% say no,60% say they didn't know to flip the blade inside out.

zl1byz
10-02-2004, 12:08 AM
<font face="Verdana, Arial" size="2">Originally posted by John Stevenson:
Standing to the right of the machine looking at it the blade comes off the jockey wheel, thru the work onto the drive wheel and over the top back to the jockey, that's anti clock in my book or does British Summer Time run different to Pacific Standard ?? http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif</font>

180deg out of phase Mid day = Mid night

I'd agree the blade turns anti clockwise when on the right side or drop side as another said, but not from the vice side. Unless the vice is on the right side, don't think I have ever seen a saw that way. http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

John Stevenson
10-02-2004, 04:40 AM
JC,
Thanks, that's a better description, towards the hinge on older saws, away from the hinge on newer saws.
I don't think puling and pushing have a lot to do with it because it's a complete band and at some point the actions are mirrored, if it pushes on the bottom it pulls on the top.

It was just an observation that I noticed, I deal with about 4 or 5 metal suppliers locally and in the last few years they have upgraded machines to keep competitive.
Some are hinge machines, some are parallel cut column machines but they all run opposite.
As these are the latest all singing all dancing there has to be a reason.

Just going slightly off bandsaws my non ferrous supplier has had a large circular type saw in for a while to cut alloy sections,
Like a wood saw it's high speed not the older slow speed geared ones, and makes a good cut.

They have just installed a new circular saw for stainless. Fanuc CNC control for blade speed, vise, conveyor etc.
It has something like a 20" tipped blade running at 3,000 rpm and it cuts thru 8" max diameter 304 stainless like butter.
They were cutting 2" when I was there and it was taking about 8 seconds per cut!!!!!!

The surface finish is like a mirror and they can guarantee length to 0.1 of a mil or 4 thou in English

They have got this is response to customers needing accurate cut lengths as many just buy in the number of parts they need.

John S.

motorworks
10-02-2004, 05:04 AM
"The surface finish is like a mirror and they can guarantee length to 0.1 of a mil or 4 thou in English

They have got this is response to customers needing accurate cut lengths as many just buy in the number of parts they need."

Guses H. Fhrist
I still have to buy in random lenghts, 10'-24'!