need a fix for Grizzly "half nut" on bandsaw vise screw

[josef]

I have a Grizzly G1758 horizontal bandsaw that I bought new many years ago. From time to time I've fought with the half nut which seems to work only half the time. I replaced it once thinking that it was worn out. I've cleaned it, lubed it, cursed it, and finally am ready to replace it with a real nut if I can find out what the acme thread size is. Anybody know?
The other option which may be better is to just replace the screw and use a regular acme nut. Suggestions?

 

[pdentrem]

We have the same problem. The drops and you cannot tighten the vice, without lifting the nut up by hand. Never looked into it.

 

[josef]

Yep. I've been lifting it by hand for a while and now it won't even reliably work that way. So I've got to do something.

 

[Glenn Brooks]

Josef, I have the same problem on my Grizzly bandsaw. I went through a goatscrew ordering a replacement nut and acme thread for my saw. The new parts are larger ID than the old one, so didn’t fit. I returned them to drizzly and they lost them for a month in their store. When I replaced the old lead screw and nut, it worked better after I dissassembled and cleaned the threads. Nothing else changed except I cleaned out all the old grease, scarf and chips.

If you find a better solution, please let me know. Grizzly’s half nut solution is a real bad idea, that they don’t seem interested in solving.

Glenn

 

[NortonDommi]

I had the same problem. Massaged the nut a bit so it would work as designed and from memory worked the seat for the spring. That was about 6 years ago and it has worked perfectly since. I trued the vice up at the same time. Making sure the vice is evenly loaded is a must and I cheat by having an Irwin quick clamp on hand for the top of the jaws on large or awkward pieces. I drilled a few holes plus made some T-nuts for the central slot to use the clamp set off the mill. Faster and stronger than the vise in many cases especially odd shaped offcuts.

 

[josef]

Well, I went the route of buying an acme nut and screw from McMaster Carr. I bought a 1" screw which was bigger than needed. I had to bore out the drizzly cast piece that the screw goes through and that the vise jaw screws to. Turned down the end of the acme screw to be the same as the old screw. It all works pretty well. Sometimes there is a little binding which is fixed by jiggling the vise jaw. I really should have ordered a left hand thread screw but at least I'm not fighting that half nut or grizzly either. I've found that fighting with Grizzly is pretty much a lost cause.
I had already been through cleaning the old half nut and working on the spring and it still didn't work.

 

[Glenn Brooks]

How did you secure the acme nut to the Grizzly nut casting? Any photos??

Thanks
Glenn

 

[josef]

Sorry, no photos. But I did not secure the nut. It floats right where the old half-nut floated and is stopped in its rotation by the same split pin that stopped the half-nut. So I kind of lucked out because the size of the nut for the 1" acme screw was just right for that to work.

 

[Swissmat]

Don't sell your bandsaws just yet ... I had the same problem with my 10x17 .. on mine there are two parts to the casting that goes around the ACME screw, the larger we'll consider the housing (214) and the smaller the offset-half-ACME nut (213) .. when my vise began to slip I considered worn out ACME threads on either the screw or the nut, but it turned out to be neither .. there is a roll-pin (215) going through the top of the housing which protrudes into the space where the nut lives, it engages with said nut when the vise handle is turned and pushes the half ACME thread onto the ACME screw .. if your vise doesn't clamp any longer, try tapping that pin down another 1/16 of an inch and try again .. as the pin wears on the casting, it'll have to be pushed further over the years .. one might be tempted to replace the wearing pin with a hardened piece of steel, but that woudl only result in the actual casting wearing down .. which is way more costly of a replacement than a simple roll pin .. hope this helps, fixed my vise issue for good ... cheers

 

[pdentrem]

I will check that out on Monday.