G4000 Speed Belt Issue

[wachuko]

Thanks for all the help guys! I appreciate it.

Just tried running the belt on the top side of the tensioner and it worked! Been trying to use the pictures in the manual and it seemed like in all of their diagrams the belt always sits underneath the tensioner. Is it a error in their manual perhaps?


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That is exactly what I went through... I just could not figure it out... Until I solve the mystery, running the tensioner over and under, depending on the speed and pulleys used, has been working fine for me...

 

[Bi11Hudson]

With the immediate need resolved, my comments will be "in retrospect". Not useless, but not very timely. . .

I have a Grizzly G-1550, essentially the same as the G-4000, just a predecessor from a different manufacturer. My drive belt is a Gates 5M720, meaning 5 mm wide by 720 mm length. The G-4000 may or may not use the same belt. I have a source a couple of miles away that sells the Gates belts. They are a surprisingly strong 60 degree belt that should not really be run by the inside surface. I have used them for several projects because the sheave is simply a threading tool.

Wachuko, the following might be of interest to you as well.

The motor drives a "secondary" pulley that contains an internal torque limiting clutch. The outer sheave, the smallest, will give ~135RPM, the slowest the machine is capable of. It is for this reason I built a reduction gear from automotive parts to get a 3:1 gear set. I will include the description. It doesn't cost much but is time consuming and requires some (lots of!) patience. But for my work, getting that reduction was worth the effort. The parts were cheap (free) because I was looking for scrap parts, not too specific.

The limiting clutch is just a spring loaded ball running against a back plate. During a heavy cut, a "clicking" may be heard. That is the ball shifting. It will require correction eventually. Usually just stretching the spring will suffice. There is(was?) an aftermarket device replacing the clutch that gave some reduction. I don't believe it got dowm to what mine will (~45RPM) but is a "bolt on" part. I don't know where to find one, I just saw a reference to it a long time back. But doing a search for 9 X 20 machines should hit on it eventually.

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[wachuko]

With the immediate need resolved, my comments will be "in retrospect". Not useless, but not very timely. . .

I have a Grizzly G-1550, essentially the same as the G-4000, just a predecessor from a different manufacturer. My drive belt is a Gates 5M720, meaning 5 mm wide by 720 mm length. The G-4000 may or may not use the same belt. I have a source a couple of miles away that sells the Gates belts. They are a surprisingly strong 60 degree belt that should not really be run by the inside surface. I have used them for several projects because the sheave is simply a threading tool.

Wachuko, the following might be of interest to you as well.

The motor drives a "secondary" pulley that contains an internal torque limiting clutch. The outer sheave, the smallest, will give ~135RPM, the slowest the machine is capable of. It is for this reason I built a reduction gear from automotive parts to get a 3:1 gear set. I will include the description. It doesn't cost much but is time consuming and requires some (lots of!) patience. But for my work, getting that reduction was worth the effort. The parts were cheap (free) because I was looking for scrap parts, not too specific.

The limiting clutch is just a spring loaded ball running against a back plate. During a heavy cut, a "clicking" may be heard. That is the ball shifting. It will require correction eventually. Usually just stretching the spring will suffice. There is(was?) an aftermarket device replacing the clutch that gave some reduction. I don't believe it got dowm to what mine will (~45RPM) but is a "bolt on" part. I don't know where to find one, I just saw a reference to it a long time back. But doing a search for 9 X 20 machines should hit on it eventually.

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Thank you for sharing the document. It continues to amaze me the amount of knowledge shared in this forum and the willingness of the members to help those that are starting this journey…

So much to learn…so much to learn…

That is one heck of a project for this newbie (me, not the OP). Just figuring out what car that came from would be a great task in itself

I saved the document for reading a few more times to better understand it all that is involved in making this.

But I have to ask… and the document is not dated to know how recent this was made…did you ever fix the 14” junker lathe referenced in the document?

Oh and lots of words of wisdom- “A smooth chamfer here may well save a finger one day.”

Thank you again for sharing

 

[Bi11Hudson]

Thank you, Sir, for the upvote of confidence. The article was written long ago, before the G-4000 was available. Twenty some years, I think. For what its' worth, I recieved a letter from the Irish Trade School commission asking permission for them to use my article in their training. Of course. it was given. The gears were from a Chevrolet 3 speed(?) automatic. I don't know what model, the shop had a machine shop in the back and the parts were laying on a shelf. The owner mentioned the trans model but it didn't mean anything to me. I got lucky on the bushing, happened to be scrounging at an aircraft parts reseller and stumbled over it.

The "junker" was eventually passed on, given to a blacksmith in exchange for some work that never got done. (I had a serious stroke) I got stuck in a chair and many things got interrupted. It was in sorta usable shape. Usable to the blacksmith, but not for any serious precision work. Such as the cross slide dovetails were so worn that one could see the curve in them.

I am an electrician and electronic repairman by profession. See the "sea story" on MrWhoopie's "Horror" page. I do some machine work as part of my hobby of building models. But not enough to call myself an expert. In essence, the article was written by a novice for other novices. That's why some things are "sort of" accurate. Not much planning, I knew what I needed and just built it as I went along. The point being is that a novice can build it, with a lot of patience.

As far as the "words of wisdom", I have many, many scars from working with my hands. Some from not thinking about what I was doing, some from pure happenstance in my job. I figure if somebody else can avoid some of my mistakes, there may be less blood shed. Since the series of machines (9X20, et al) is so wide spread, I figured others would have the same needs.

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[chip maker]

I have owned my G4000 since new in 2000 and thru the years have had issue with the belts. So awhile back had nothing to do so checked this out again as I was using two belts for different setups. Finally found a good article and found that the biggest issue is there is really an adjustment issue with the motor adjustment and the first drive pully adjustment. The motor cog belt can be adjusted by the motor and by the cogged belt drive pully. The trick is to be sure to use the belts that your machine was designed for, and it doesn't take much of a change between these two adjustment points so it's a time game to get them set to where the pully belt will work on all the pullys without using different belts. Believe me it takes alot of fouling around to get it just right, but it can be done. Also, there is two cog belts for this machine depending on when it was built. Without having the correct cog belt can cause problem with the pully belt sizing as there is only two of those listed. All this depends on date of manufacture. Good luck !!!