Pm-1228 Replacement V Belt?

Not wanting to be argumentative but when I called technical service at Fenner they said "no" and their answer was emphatic. They weren't willing to even discuss a part time reverse application, it was "no ifs, ands, or buts". Guess I didn't get to talk to the right person.

I sincerely wanted to put it on my PM1340GT when I called them.

Here it is on the inside of the sleeve that the belt comes in. I keep a stock of the stuff and have a sleeve handy:
fenner.jpg
 
The belts on my PM-1440GT also had the black dust problem but it eventually went away after time. After I did the 3 phase motor conversion I changed the factory belts to Gates Tri-power because I needed a slightly longer belt. No dust with these.

I think a lot of the vibration problems some have with v-belts are due to not having the correct tension, usually too low. The Gates tension gauges are about $10 and you can get all their tensioning data online.

The belt on the 1228 is most likely a metric SPZ (9.7mm x 8mm). The Imperial equivalent would be a 3L (3/8" x 5/16"). There are plenty of online belt size calculators you can use to get the correct size or you can measure the length of the outside of the belt you have.
 
Jay, I think the Gates Tri Power is a good solution. Thanks for the tip on the tension gauges. Is this it?

tensioner.jpg
 
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Yeah, I know this is an OLD thread, but I have this same question as originally stated and looking for an answer.

I am at the end of travel of the adjustment for tension on the v-belt and after doing some digging around, it appears that the belt says 10 x 838 for the dimensions. The belt actually says something like 838 x 8 (10), so I went to Grizzly's site and found a lathe that appears nearly identical. They list the actual dimensions in their manual and that is stating 10 x 838 for the drive v-belt. So I went and got one. Nope, no dice. Too short. But the thing I found interesting is that the belt on the PM-1228 is likely an 8 mm, but I haven't measured it yet. It sets deeper in the pulley grooves than a belt should. The 10 mm belt I got actually fits the pully correctly, in that it is flush with the lips of the pulley, instead of recessed as the belt is that came with the lathe. So I am thinking that there is a practical difference between the 8 x 838 and the 10 x 838 belts, in that the 10mm sits higher in the pulley, and that replacement belt actually needs to be something like 10 x 870, or thereabouts, to compensate for the outside edge sitting higher in the pulleys.

I contacted PM, and they are sending me out a free replacement, which is nice of them. Mike said the dimensions I was using should be correct, and said I should check out the measurements on the new one to see how it compares. I haven't really used the lathe all that much, so it is disappointing that it got so loose so quickly on me. I want to do some tinkering around with knurling, so I don't want that to get the belt slipping on me in the middle of that.

As an aside, I am thinking what I might need to do is to remove tension on the tensioner when I am not using the lathe, and only tighten it up just prior to me using it. Might save me from having to replace the belt every year when it is under tension all the time the lathe isn't being used.

So has anyone else actually figured out the CORRECT size belt for this lathe? Save me from having to do the hunt and peck method of finding that magic numbered belt?
 
I installed a gates truflex 1345 on pm1228 day one. They must have test ran mine because black belt dust was all over inside when I received it. After cleaning it all up the gates hasn’t made a mess yet. I tension it enough to have about a 1/4” movement or that I can twist it 90 degrees. I’m a diesel mechanic and that’s what I was taught in school.

I don’t think you need to release tension on the belt when not in use. That’s really more for bandsaw blades and their adjustment springs. No problem with my gates belt. Like I say, adjust the tensioner so that you can twist the belt in the middle 90 degrees with your thumb and fore finger. Or allow about 1/4” up and down movement. You’ll be good to go. No gauge needed. Been doing that 16 years at my job. Never had a problem with any type of belt.

Here’s is the package my belt came in. I also tried a Truflex 1350 but switched to the 1345 so the tension pulley wasn’t adjusted so far.
 

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I did some measurements yesterday, and the top edges of the pulley groove are roughly 9.97mm wide. A 3/8" belt will be 9.5mm, so pretty close. I think a 10mm belt will just fit better. Height of the pulley groove is 10.37mm and at the bottom of the groove, 4.08mm. I measured around the pulleys on the outer edges and came up with 885mm (34 7/8"). Distance between centers of the motor pulley and the drive pulley is 11.5". Diameter of drive pulley is 5.5" and diameter of the motor pulley is 1.75". This is using the smaller pulley on the motor and the larger pulley on the spindle (for the slower speed).

I sent all these dimensions to a company that specializes in V-belt replacements (https://www.vbeltsupply.com/), so I am going to see what they can come up with.

But thanks for some leads on the 3/8" belt candidates. Personally, from what I have been learning about V-belts VERY recently, I think the stock belt that comes with this lathe (8mm width, I believe) is just too narrow and sets too deeply in the pulley grooves. It will apparently work, but I don't think it is the optimum size for this application. But I'll know more (hopefully) when I get more belts to try to see what seems to fit best.

Personally, I think I am going to back off the tension wheel whenever I am not using the lathe. I think it will reduce the stretching that belts undergo over time and keep belt changes down to a minimum. Maybe a better quality belt than the stock one wouldn't be as much of an issue, however. I haven't used the lathe much at all in the past year, so it is not from running the machine that the belt stretched like it did.

BTW, I spent time last night looking for every instance I could find of a v-belt being used on a lathe, and ALL of them had the belt sitting flush with the edges of the pulley groove. Of course, might be a case of "inconsequential differences". :)
 

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Well, I went and ordered several different sized belts for the 1228 from an outfit called OffRoadBelts.com. Great people and very reasonable prices, BTW. So when they came in, I tried them all, and the best fitting one was the 10mm x 875mm one. Guess I could have saved some time and trouble just by going by Bryan40g's suggestion, but I just wanted to double check for my own satisfaction. But that did give me a good starting point to work around. Plus I had something perhaps different in mind to try. I actually went and bought some small tools for installing and removing V-belts, but I decided I didn't want to pre-stress the belt by having to force it up and over the lips of the pulleys to place the belt in the grooves. My idea was to pull off the pulley from the motor shaft, position the belt into the pulley grooves, and then slip the pulley back onto the motor shaft. With the 10x875 belt, this was pretty much an EXACT fit and worked like a charm. Only had to do some minor tugging to get the pulley onto the motor shaft, lining it up properly, tap it lightly with a soft mallet, and it was done. Actually it feels like I won't even need to use the tensioner at all to start off with as it is tight enough, as is. I also selected a cogged belt, as I felt it would be a better match for this application than a solid belt. Apparently cogged belts are better on smaller pulley diameters.

I also received the free replacement belt from PrecisionMatthews (thanks Mike!). Oddly enough it states right on the belt that it is an 838mm long belt, and it measures as being 9.5mm or so in width. I bought a belt measuring tool, and according to it, this belt actually measures 10mm x 875mm, regardless of what is imprinted upon it. Little wonder this was so confusing. I did pass this info onto Mike at PM, btw.

So all is well that ends well. Have the new belt on the machine and a couple of spares to boot.

Pics are attached of the OffRoadBelts cogged belt mounted on the PM-1228 and then measurements of the replacement belt I got from PM.
 

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Tired&Retired said:
Well, I went and ordered several different sized belts for the 1228 from an outfit called OffRoadBelts.com. Great people and very reasonable prices, BTW. So when they came in, I tried them all, and the best fitting one was the 10mm x 875mm one. Guess I could have saved some time and trouble just by going by Bryan40g's suggestion, but I just wanted to double check for my own satisfaction. But that did give me a good starting point to work around. Plus I had something perhaps different in mind to try. I actually went and bought some small tools for installing and removing V-belts, but I decided I didn't want to pre-stress the belt by having to force it up and over the lips of the pulleys to place the belt in the grooves. My idea was to pull off the pulley from the motor shaft, position the belt into the pulley grooves, and then slip the pulley back onto the motor shaft. With the 10x875 belt, this was pretty much an EXACT fit and worked like a charm. Only had to do some minor tugging to get the pulley onto the motor shaft, lining it up properly, tap it lightly with a soft mallet, and it was done. Actually it feels like I won't even need to use the tensioner at all to start off with as it is tight enough, as is. I also selected a cogged belt, as I felt it would be a better match for this application than a solid belt. Apparently cogged belts are better on smaller pulley diameters.

I also received the free replacement belt from PrecisionMatthews (thanks Mike!). Oddly enough it states right on the belt that it is an 838mm long belt, and it measures as being 9.5mm or so in width. I bought a belt measuring tool, and according to it, this belt actually measures 10mm x 875mm, regardless of what is imprinted upon it. Little wonder this was so confusing. I did pass this info onto Mike at PM, btw.

So all is well that ends well. Have the new belt on the machine and a couple of spares to boot.

Pics are attached of the OffRoadBelts cogged belt mounted on the PM-1228 and then measurements of the replacement belt I got from PM.
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The inside to outside correction for a 10/10x metric belt is 38mm, which is why you measure 875 and the other one is 838. Also the Li next to the 838 denotes inside diameters. If it LA it would be outside diameter, and Lp with be pitch diameter which is part way down the belt. Metric belts are even more confusing than standard belt measurements.

Good for using the cogged belt, much smoother and better power transfer around small diameter pulleys.

Stay away from the fenner power twist. I have witnessed several seriously worn pulleys from running long hours on them. We keep it at work as back up for odd size belts that we don't stock but replace them as soon as we get a proper v belt in.
 
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