My Chinese Mini-Lathe Experiences

[FrankenMech]

Measuring just one pitch does not work. There is too much of a variation in a used belt. Lay the OEM belt out and measure along 10 teeth, then divide the distance you get by 10 and you should be right on, no guesswork. This method works well on timing belts which is what you have on the lathe.

If it is a 3/16" pitch that would be 0.1875 x 10 would measure 1.875". You can count 20 teeth and divide by 20 also. You are showing about 7 pitches in your drawing. Measuring over a large distance reduces the measurement error. It is like using multiple turns on your rear wheel and counting input shaft rotations when determining gear ratios.

Length can also be determined by marking the belt, aligning the mark with a measuring tape, then rolling the belt a full revolution until the mark aligns back with the tape and note that measurement. Using the rolling method is slightly better than a string around the pulleys or over the belt. There is some error in the string method because the actual pitch diameter is figured where the reinforcement strands are placed in the belt. The rolling method compensates for that pitch diameter error.

[spaz12]

As popular as those lathes are you would think finding a belt would be easy.

I'm assuming that you already know about littlemachineshop.com? And this belt? www.littlemachineshop.com/products/product_view.php?ProductID=2811&category=1963256915

[FrankenMech]

I think the little machine shop link has been mentioned before.

[90GTVert]

I honestly haven't put much time into looking for a stock belt. I guess I just took it from TimNummy that replacement belts weren't easy to find.

[190mech]

I did a bit of looking and didnt see any belts of 3/16 pitch,it might be best to upgrade to a common pitch pulley so a standard belt could be used..Perhaps shop for some that are matched to one of the belts youve already bought..

[90GTVert]

There's also stuff like this, but I haven't taken it apart to measure :
www.ebay.com/itm/NEW-Asian-Mini-Lathe-7x10-12-14-Gear-Belt-Kit-Grizzly-8690-and-others-/151730631517?epid=632121896&hash=item2353d9b35d:g:Dt0AAOSwA3dYEn7-

From that ad :
"Note: This is an XL Pulley/Belt System,INDIVIDUAL COMPONENTS WILL NOT INTERCHANGE WITH THE OEM BELT/PULLEY SET-UP THE MINI LATHE COMES WITH STANDARD, XL is .200" pitch and the OEM belt is labeled 1.5 x 70, !!there is no such thing!!, the actual belt pitch is .1875" and is not an Industrial Standard Manufactured Timing Belt."

[190mech]

That ad appears to be for the 2 speed model which uses a jackshaft between the motor and spindle,shorter belt and top pulley has a smaller shaft ID..
In TimN's vid he just changes the lower pulley and belt,guess he didnt want to dig into the upper pulley fitment,,
www.youtube.com/watch?v=3CXZCu3T7Mw&t=147s

[FrankenMech]

There are places to get 3/16" pitch belts but you have to look hard. 3/16" was a standard pitch for a long time, mostly obsolete now. The exact length may be a problem but that is why there is adjustment for belt length.

Google: "3/16 pitch timing belt" will come up with some sources and as usual a lot of garbage results...

Personally, if replacement belts are a problem, I would just get some new pulleys and machine them to fit for a metric pitch belt.

[190mech]

I retried that 3/16 search again,found nothing,,the 3/16 is always the belt width..I even tried 4.76mm pitch belt and came up with the same thing,,0!
I think the challenge will be to keep the drive ratio close to the same,but not crash into other parts when replacing the pulleys to a common pitch..

[90GTVert]

I tried searching for 0.1875 pitch timing belts, but I get the same result as John and it keeps being either the width or some other number on the page.

I can't say I've exhausted all efforts for a search though. My parents wanted to have a yard sale (hate yard sales so much) and I've been stuck cleaning out attics and sheds and whatnot looking for $500 worth of stuff to sell for $5. My father just asked me this morning when they thought they needed more stuff, "Should we see if we can find some tools to sell?" Who is this man? I don't even know him anymore. lol On a related note, if anyone wants to buy a desk or an old Christmas tree or a 50ft VGA cable, they're out in my yard right now.

[FrankenMech]

"3/16 pitch" will come up with mostly belt widths and a lot of pulleys, part of the garbage in a google search.

'Inch' drives are going the way of the Dodo, and rightfully so. The rest of the world is Metric.

Hmmmmmm, I wonder what measurement system Aliens will use when we eventually meet them. If we survive the encounter or live that long. They probably won't even use decimal numbers. Can you count in Octal? Supposedly we are gradually losing our little fingers which will leave us with 8 fingers to count on. Maybe everything will be binary. You can count up to some really big numbers with your fingers in binary.

www.asisurplus.com/cgi-bin/item/33825/30110/MFG%2D%2DAT5780
picclick.com/135236-Gates-5005M-Powergrip-HTD-Belt-3-16-Pitch-282107162984.html

Even when you find a 3/16" pitch belt it will be mostly the wrong tooth form or the wrong length.
My suggestion is still just to machine a couple metric pulleys and replace the drive before the OEM belt breaks.

That is still a popular lathe so somebody will come up with parts.

Now with my giant VOEST lathe parts will always be a problem or at a huge $$$ premium.
www.lathes.co.uk/voest/
Mine is one of the later, larger models with 5KW/7.5HP drive.
Now that VFD drives have come down in price I can get it up and running.

[AtariGuy]

Thinking back as i watched this fellers videos on the lathe, he had a problem and a solution you might-could steal? Some more info and links in the description?

[FrankenMech]

Very good video, it bears looking into. I had to laugh when he stripped the heads on the belt guide screws though. He should put a belt guide on the other side of his new pulley also. Getting the motor aligned so the belt rides on the pulleys without riding over against the guides is tough but it is worth doing for long belt life. It is interesting to note that he found the two pulleys to be different pitch sizes.

Also, a drill bit can be used as a boring bar when clamped in the tool post. There is no need to file and sandpaper a pulley bore like he did. Adjustable reamers are also available for accurately sizing small holes. Drill bits are notorious for drilling oversize holes.

I have been trying to find my way clear to buy a VFD for my lathe. I went to look at the VFD specs and it is not available from the seller. One of those Amazon "Currently unavailable. We don't know when or if this item will be back in stock." deals.... Oh, well, car repairs and storm damage is currently eating my budget alive.

[90GTVert]

I haven't messed with the lathe much lately. Never have got it apart to check into the belt more. I did at least make something with it yesterday. I had to repair the wall in one room where a bed with casters that don't lock sits on a laminate floor. The bed has slid around enough to damage drywall a little. After repairing that, an area rug was placed under the bed and thick felt was applied to the frame where it could contact a wall. That helped a lot, but it could still move some. I made a foot to replace one of the casters. The top looks essentially like the wheel shown, but the bottom is just a cylinder that's threaded to accept a delrin piece that I made so the steel won't be on the rug or floor. Just having 1 caster replaced made it better. Not sure that I'll bother to make the rest.


EDIT : Oh, and I'm picking the bed up in the pic to show that it actually locks into place as it should. Didn't want you to think I made it too short. That's entirely possible with me, but not this time.

[FrankenMech]

Nice job! Did you 'lock' it in place with JB??? LOL

The VFD is back in stock but so many things have to get fixed first. I don't want to buy it until I am ready to install it in case it is defective or something. My ADD makes me work on things kind of sporadically. I suck at getting things done.