Grizzly bandsaw troubleshooting

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Glenn Brooks
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Grizzly bandsaw troubleshooting

Post by Glenn Brooks »

Hello All,

Recently I bought an old, used Grizzly 7x12 bandsaw. When I got it home I discovered the vise didn’t tighten down in the work. Disassembled the lead screw and nut and figured maybe the nut was worn. So ordered a new screw and nut - twice, as the old model,is discontinued and they changed the diameter of the acme thread.

Long story, the new parts act exactly like the old ones. grizzly’s acme nut is only threaded on one side of the casting- apparently to allow the vise jaws to be slipped out of the locked position for easy removal??

How do I go about figuring out what’s wrong with the vice jaws??

So,far their design is a mystery to me... these things aren’t that complicated. Dead simple actually. But I am mystified about how the vise doesn’t lock down on the work??

Any advise.

Thanks,
Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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Harold_V
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Re: Grizzly bandsaw troubleshooting

Post by Harold_V »

Pictures, Glenn. Also, check to see if there's a sliding member that locks the nut down against the screw.
You haven't really detailed what's actually wrong. Do the jaws fail to tighten, or does the nut slip away from the screw? Does the size of the material make a difference? Is it really Acme? If it's split, there must be a way for the nut to be restrained, otherwise the flank angle of the thread will push the nut away from the screw. If there is no locking device, I suggest it's not an Acme, but a buttress thread, or even a square thread. More information needed, Glenn.

H
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curtis cutter
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Re: Grizzly bandsaw troubleshooting

Post by curtis cutter »

Is it the kind of clamping action where when the clamp is turned CCW it totally releases the movable jaw to slide in and out then when you tighten CW it engages the clamping action?
Gregg
Just let go of it, it will eventually unplug itself.
Glenn Brooks
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Re: Grizzly bandsaw troubleshooting

Post by Glenn Brooks »

Gregg hit it now the head. When I tightened the clamp onto the work, the clamp(mobeable part of the vise) simply releases all tension. It doesn’t hold the work in place.

GPB
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Harold_V
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Re: Grizzly bandsaw troubleshooting

Post by Harold_V »

If Gregg is right (and I have no doubts he is), then the nut and screw aren't likely Acme, but If they are, then there must be a means of locking the nut down, so it can't move away from the screw when pressure is applied in tightening the vise.

Is there a spring loaded device on the nut assembly? If there is, it may be the lock I mentioned. As I'm not familiar with that saw, I have no way of knowing, but it's one of the ways the nut is locked on to the screw, yet easily released for large adjustments of the moveable jaw of the vise.

H
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neanderman
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Re: Grizzly bandsaw troubleshooting

Post by neanderman »

Sounds like a woodworking-type, bench vice, with quick, traversal. They work okay for woodworking, but it's not the kind of vice I would use for metalworking.
Ed

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Glenn Brooks
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Re: Grizzly bandsaw troubleshooting

Post by Glenn Brooks »

FYI. Called Grizzly service center today and learned two things: the nut is something they call a gravity locking device. Meaning when you spin the hand wheel the nut rotates sideways about 140* or so and locks against the top the casting it sits in. This engages the acme screw with the thread inside the nut. Reverse the direction of the screw and the nut twists in the opposite direction and ‘drops’ open, thereby releasing tension on the work.

Secondly, Grizzly cautioned the big thing is, DO NOT GREASE THE SCREW OR NUT. only use ISO 68 machine oil for lubrication. If you apply grease, the lube picks up metal,shavings and apparently interferes with the thread operation.

So I took a close look at the thread and nut assembly. I found it was clogged with many years of cuttings, swarf, and various metal bits - all locked together with dried machine oil and the ubiquitous gray slime we all know from heavily used lathe beds. This crud was interfering with normal movement of a small, spring loaded plunger in the acme nut, and had also built up inside the thread relief. I cleaned all that gunk out, remounted and properly lubed the screw and nut relief, and the vise works just fine now.

Now all I have to do is figure out how to tune up the little hydraulic ram, so the saw blade doesn’t stall the motor when cutting to quickly. Probably actually have to read the operators manual. :shock:

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
curtis cutter
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Re: Grizzly bandsaw troubleshooting

Post by curtis cutter »

Glenn Brooks wrote: Wed Nov 28, 2018 12:25 am FYI. Called Grizzly service center today and learned two things: the nut is something they call a gravity locking device. Meaning when you spin the hand wheel the nut rotates sideways about 140* or so and locks against the top the casting it sits in. This engages the acme screw with the thread inside the nut. Reverse the direction of the screw and the nut twists in the opposite direction and ‘drops’ open, thereby releasing tension on the work.

Secondly, Grizzly cautioned the big thing is, DO NOT GREASE THE SCREW OR NUT. only use ISO 68 machine oil for lubrication. If you apply grease, the lube picks up metal,shavings and apparently interferes with the thread operation.

So I took a close look at the thread and nut assembly. I found it was clogged with many years of cuttings, swarf, and various metal bits - all locked together with dried machine oil and the ubiquitous gray slime we all know from heavily used lathe beds. This crud was interfering with normal movement of a small, spring loaded plunger in the acme nut, and had also built up inside the thread relief. I cleaned all that gunk out, remounted and properly lubed the screw and nut relief, and the vise works just fine now.

Now all I have to do is figure out how to tune up the little hydraulic ram, so the saw blade doesn’t stall the motor when cutting to quickly. Probably actually have to read the operators manual. :shock:

Glenn
Does yours have the pump and lubrication system with it? If it does, I would think that the water based lubricant would flush out the debris.
Gregg
Just let go of it, it will eventually unplug itself.
Glenn Brooks
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Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Grizzly bandsaw troubleshooting

Post by Glenn Brooks »

Gregg, it does. But I do not yet know if it works. or if the prior owners used it... The screw assembly and some parts of the outside of the base were heavily clogged with metal shavings. The machine surfaces were not clean by any means when i bought it.

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
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