Well we have had our Eldorado in the shop since the 18th of Dec. Hopefully tomorrow we will be able to actually get some chips cut by it. (These will be the 1st chips!!)

We have had a string of little issues with the machine since we got it assembled here. Most of them were minimal, but the issue that I just solved is just DUMB. From the other forums about these machines I know I am not the only one with this problem.

The key inside the R8 spindle for the mill head is too big. This means that the sloppy collets that came with the machine fit in, but not a single other R8 collet would fit, either american made, or import. SO this means that i had to tear the WHOLE mill head apart, and remove the key, so I could remove .050" off it to make the collets fit. This is just crazy in my mind. It took me a full day to disassemble the head, fix the issue, and re-assemble it.


Although many say this machine is nothing short of great, I am so far less than impressed....... hell you can't even bring the head up to full height in some the gears, due to pulley interference!

:eek:

Hi Devinchi,
I too have a key inside the mill spindle that is waiting to be shaved down. I picked up a nice set of r8 collets on eBay and finally got around to needing to use them. But, the keyways are too shallow for the deeper key in the spindle. Yah! That was crazy. I'm going to get a collet holder with inserts anyway so i'm not going to take it(the key) out until I have to.... That may be sooner if the collet holder keyway can't be deepened.
What's going on with that belt/pulley interference? I didn't notice any restrictions other than the crank hits the protective hood, but only when it is about as high as it goes?
I'm not saying much negatively because I know that for the price this shoptask is well worth it. I WILL say that some of the places they chose to cut costs on the machine were inappropriate....yet nothing that can't be rectified by the user.

Another thought....
I don't know yet if there is a standard for keyway depth on R8 collets, but if so then shoptask would be wise to follow it. Maybe some extra communication with the china plant on quality control.
There is no need to have the key so deep as the collet is pretty much drawn tight and locked with only a sliver of a key.

Here are 2 pics of the interference we have with the top plate of the quadra lift and the pulleys.

They are rather large pics, so I am not posting them directly.

http://fareast4x4.com/shop1.JPG
http://fareast4x4.com/shop2.JPG

This shows that we have interference with 2-3" of travel left in the head.....and this interferes in more gears than not. So we have all the travel advertised, but just not in all gears. And for some of the gears we whould have to take a SIZEABLE chunk out of the upper plate to have it clear.

I see your problem.
I can only suggest to go with a shorter belt from the spindle pulley to the idler pulley. I have the Bridgemill model and so far it clears. This may be a problem here too though if I select a slower speed and the pulley centers change with the belt location. I will find out in the future when I need a slower speed and change the belt groove selection. Its how the pulley ratios are that may change the pulley centers.

Devinchi...
Noticing your DRO... I sure want to add that to my machine for manual use. I was making a part with a bore and went too visual and made the bore too large. Fortunately it wasn't critcal as the mounting holes surrounding the bore still landed in solid metal.

Ya, we got the Shoptask as a CNC, and just decided to step up and get EVERYTHING. So it has the CNC, Ballscrews, DRO, all the toys.

We finally got the machine up and firing on all cylinders. Some inexpensive wood proto's today. tomorrow...metal!

I've never run a Shoptask, but when I looking into my first personal machine, I lucked out and got an original Emco M8; one of the last built in Austria. Now they are all farmed out to Taiwan, or the current lowest bidder.

The great thing about it is that the milling head bolts on the back of the lathe, in the middle. Looking at the Shoptask, with the milling head on the headstock, I couldn't see how much could be done except drilling holes in the chuck!

And the EMCO is all gear driven, no belts. The only bad (good) thing about it is that the screws (longitudinal feed, mill head height) are 16 TPI, so it is really precise but takes forever to raise the head.

Are there any advantages a Shoptask has over an EMCO?

I've never run a Shoptask, but when I looking into my first personal machine, I lucked out and got an original Emco M8; one of the last built in Austria. Now they are all farmed out to Taiwan, or the current lowest bidder.

I have not seen Emco in many years. Are you sure you don't confuse it with Enco? (I assume that was Enco's intention.) They are what you describe.

They are still alive and well:

http://www.emco.at

They mostly do CNC now; they have a mill the size of the Taig that was something like $17,000! (http://www.desktopcnc.com/emco.htm)

'This Austrian based company has made machine tools since 1947, note this is not to be confused with the Far East company Enco. With interchangeable options the mill can mimic the control operations of Fanuc, Heidenhain, Siemens or EMCOtronic.'

Blue Ridge machinery handles the parts and accessories, but I don't think Emco makes the Mill/Drill anymore.

I have heard of the Enco, and that probably was intentional. I don't think they were nearly the quality of Emco. I couldn't find much at their site, the script that lists the products keeps crashing!

at a glance and not having the tri-power i want i'd first have to say it looks as the pullys have been mounted upside down and backwards ? is it a possibility ? it would make for a lot more room if large end was opposite

I had the same problem on my Eldorado. Bent the pulleys pretty good moving the z axis up. Took me a while to straighten them out. That's the one really big thing I don't like about the Eldorado, the pulley / belt system. It makes it really easy for belt changes, but even with the best belts it slips under heavy load. I'm currently upgrading my (2) shoptasks with 2 hp three phase motors. I'm still trying to come up with a solution on the pulleys. If anyone has got a better idea, I'm all ears.

Richard

Hey Bloy, and others,

I found an easy work around for the R-8 key in the mill head. I had the same problem you describe, what I did was disassemble my mill head, and take the quill shaft out so I could get to the Key way, (I did have thoughts of grinding it down alittle), BUT, once I got it dis assembled, I noticed the keyway is held in place with two screws, that have little washers on them. So........ just for fun, I put the the washers UNDER the little tiny block that holds the key. this pulled they key way, out of the quill by the thickness of the washers. I tightend the screws, put a little tiny dab of loc-tight on the threads. I then re assembled the mill head. It worked like a charm, the economical R-8's that I got from enco, then fit in like a glove. I have ran it like this for the past 3 years with NO problems. I also run 2 HP, variable speed DC moters which will run from 0-3,400RPM. Since most of my mill work doesn't really come close to needing 3,400 RPM. I just use the (slightly slower pulley range than mid range), to get more power pulley advantage. If for some reason I do need higher RPM, I go up one pulley. NOTE: The DC drives I have, have an optional selector switch to choose between RPM Tach feedback, and a selector for RPM and one for Torque..... I use the RPM feedback tach and the torque setting this keeps the power up, even for slow speeds like power taping i.e. 50 RPM......

Also, if you using the CNC balls/screws for shop task, set you Z return spring where it is slightly stronger than the wieght of your quill, this will keep out back lash (not that there is a hole lot).

Further, add a second Ball Nut from Nook industries just like the ones on the machine one for each X and Y, and set it up as a double nut, to add some preload. Again this tightens up and elimanates back lash in the axis. A singular ball nut from nook is about 0.004 per foot. with the double, you can cut that down to about 0.001 per foot. NOTE: Take the time to ajust your gibs on X and Y.....if it just doesn't seam to what to do right, Remake/regrind your own gibs...... I noted mine had a slight "warp" in it, so I had the gibs remade/reground out of Steel. No problems after that.

Oh yea, one other note: On the X axis, the ball screw CNC gear, has a tiny, tiny set screw.......this will start to slip on you after a while, and you will notice some play in the X axis shaft that will drive you nuts trying to figure out where the problem is. Take it from me, take the gear off, redrill it to accept a 0.25 flatbottom grub screw, (the ball screw already has a grind flat for it to catch on the ball screw). You X-axis is without dought your heaviest and hardest to move.

goodluck,

Scott

I have been considering the shoptask for yrs now and am really close to having the funds for purchasing the new version "tri power" butt ! after reading some of the issues with pully's, backlash, gibs, set screws etc. I'm really having some second thoughts. I have been figuring on this machine purchase being a source of income for retirement, not just a hobby. I'm curious if these issues have been passed on to the source and what you might have received as support from them. it wouldn't be a very long wait and i could aim higher for a cnc bridgeport or other higher end machine. the main interest with this machine was having both lathe and mill. I don't know of any in my area, i'd sure like to see one up close. what say you guys, would you admit to any second thoughts like wishing you had done something else instead ? I'd really like to hear some serious imput here. I'll say "papabear10"s input was rather respected and spending $10 g's to fix and adj. so that i can get some tollerances is rediculus sounding. I presently work on a Monarch cnc verticle turning center and run tollerances of +- .ooo5 and thats on a 48" chuck this little guy should be able to get better than .oo4 to 12" !

For the money, I feel it is a great deal. There are a few people doing gunsmithing that use this machine and make a living doing it. That being said, if you are doing something else, production type work.... it still can be done, but you would need a few upgrades. I own two of the shoptask machines. If I were to do it over I would:

order a plain stock machine
pull the motors off & upgrade to 2-3 hp with VFD
add my own steppers/servos
add impulse tach for syncing of rpms
add limit switches
add coolant system
add lighting

Then.... you would have a very capable machine.

Richard

Note: with mine and the double nuts, on x and y, I am holding 0.001 per foot,
most of my parts are under 6" on average and truley it holds no appreciable diviation from my specs at this level, but having said that, your real practicle milling envolope with Lathe chuck removed is just about 10" diameter, shop task says it is 11x18, but I am including stuff for clamps and stuff.........

The weak point in my opion of the Mill part is the head, even with the arm locked down, and high horse power motors, you get alot of chatter if you try to take a 3/4 carbide mill and hog out a .125 cut at F9 in AL.......alot of that vibration comes from the table, it need reinforcement in a bad way, further more stability of the 5th arm would also help.

If you are going to be doing Hobby level income (I make Real Guns, Paintball guns, and other various widgets for these things). It does a good job for what it is.

Now if you want to do larger things and hog chips faster then yes, get you a BP and retro fit it your self.

The Lathe part of the shoptask: The Lathe is ok as well, like all machines once you get used to how it performs, you learn what to do to overcome its limitations. It would be dought full that you will hold a 0.0005 tolorance over any length over a foot on the lathe. There may be others who will argue with me, and that is fine, that has been my experience. Truely though, I have yet to run into a job that I do that truely requires tolorances greater than 0.003 in a singular direction....

A part that you could run on a commercial CNC Lathe or Mill (average size) in 1 hour, may take you 3-4 hrs on your ST, since it really is at best a light industrial machine.

Would I buy it again? For what I do, yes I would, I have been overall very happy with it. Most of the problems, you can fix. Of all the "Hobbie" level machines you can buy, the Shoptask blows them all away. It is by far the largest of the 3 in 1's.

later,

scott

Cruiser,
Steer clear of Shoptask. I bought a shoptask machine back in 2000 and hated it. Not much on the machine ran well right out of the crate. After much time (years) and frustration, I was able to finally fix it, I had to redesign the drive system, employing a variable speed motor to drive the lathe and the mill required all sorts of improv.. I now have a 5 gal. bucket full of old shoptask parts. The lathe part of the machine is finally as accurate as any that size. The mill works pretty well on soft materials such as plastic. However, when you try to cut aluminum or steel the lack of rigidity really shows! One other importaint point: You just don't realize how valuable a knee is on a mill until you don't have one! My advice is buy a real mill and a real lathe on the used market! I finally did and now seldom use the shoptask. Plus if you buy a used machine you might be able to get your money back if you decide to sell it. I don't think you'll do the same with a new shoptask.

My machine is now a decent little CNC machine. But boy did I pay a high price for it!

Just my 2 cents,

Chris
P.S.
Don't count on the machine arriving on time, Mine was the typical 6 mos. late.

There is ABSOLUTLY NO WAY you can compare the Shoptask to a B-port, new or used.

They are not *that* type of machine. If you need to do fast, heavy cuts, why do you think a 3in1 would do that better than a dedicated 2ton mill?

I gunsmith on my eldorado (stupid name) and have had some issues... no more than any other piece of machinery I have bought.

Hey all, I did in fact stay away from the eldorado altogether, in fact, i was on the net and waiting for the seller to open shop so i could call and order when i cam across this and another link, i also saw the add for "Industrial hobbies" machine and took a look. I went from min's to ordering straight to owner of the "IH" mill and some many months later am going to call it up, running, and on line today one way or another !

I have had a new Tri-Power since June. I like it, although I've never done machining professionally. I am an engineer and wanted to do my own prototyping.
The Tri-Power has a longer x axis and the mill is centered. So the mill pulleys are very far (>20 cm) from the mill lift mechanism. There is no longer any chance of interferance.

I've only used China mfg R8 collets from Shoptaks and Enco, so I don't know if the key is still a problem. Everything seem fine to me.
Backlash is disappointing. With split nuts, one should be able to adjust it out, but I have not been able to reduce it satisfactorily. I would not recommend this machine without the DRO. With the DRO backlash is a minor pain. I assume that with ball screws it is much better for CNC.
The space over the work area is rather confinded by the bidgemill structure. So if you are accustomed to a Bridgeport or similar, you may find the Shoptask too limiting. However, for the money, a flexible owner will be quite pleased once the problems are addressed.

I had many out of box problems, some sever. Shoptask addressed all of them in a timely fashion with no hesitation. The suggestions offered by the Alchemist and others preceeding him will yield a fine budget cost, small shop machine.

Spencer Lovette

well i have been waiting 4 and 1/2 months for my tri-power and in 1 more day it is due. ordered with dro,ball screws and 4axis servos. i hope i did not waste ten grand????? good old john promised it would hold .001 tolerances,we will see.will keep posted. :confused:

I would not have sunk $10k into a Shoptask.. no matter the bells and whistles.

I paid a little over $3k with DRO and lifetime warranty (used it for several start capacitors and a wiring harness, also the DRO PS failed).

Unless the newer models addressed all of the issues (motor caps, location of lathe oil drain, location of the mill pullies, better quality hand cranks, pluss additional fit and finish issues).

I hope it turns out well for you.

I thought I would jump in here. I am not a machinist by trade. I design ceramics and was trained as a potter many years ago. I make tooling for ceramic reproductions for the tabletop industries (yeah, dishes and serving pieces). This machine is quite good for my needs to machine Ren-Shape and non-ferrous metals to make models from which I can make plaster molds and then rubber molds from the original plaster molds. Maybe I got a good machine I don't know. I followed alot of instructions and advice from The Alchemist's site as well as some others I found.It was fine right iout of the crate.
I put ball screws on and 3 axis CNC from Camtronics and for me, the machine works very well, but I must quantify this by again reiterating that I am not a machinist. I wanted to learn how to machine and this serves my needs very well. My future plans are to get rid of all the belts and pulleys and put on some higher horsepower motors with a VFD, but that's for some time in 2007.

Happy holidays to all!

Best

Jonathan in Denver

The Shoptask is sold as a MILL and LATHE (I could care less about the Drill).

Its a 5 out of 10 on each count. It can be upgraded, which is a plus, but again, I would have bailed if my bill came to $10k.

TO many quality issues.

well i have new tri-power 2 weeks now. i am not a happy camper. of all the
claims made on there website at shoptask.com, i can only confirm one, it is yellow in color. more to come later.:( :( :(

I have had a tri power since september this year, and have been, for the most part very happy with the machine. There have been a few grumbles (my toolpost was machined incorrectly (too high) and came with metric toolholders, my tailstock came apart because the recess for the set screw holding the acme nut was too shallow), but other than that I'm happy.

Before I bought mine, I considered all of the options I had available to me at my budget: mini lathe and mill, other kinds of 3 in 1's, the shoptask. For me, the biggest issue was capability: the shoptask is way bigger and has so much more work surface. Any of the options I was interested in required initial work to get them up to speed....the most being the mountain of parts to get the mini lathe and mill where I needed them.

I finally settled on the Shoptask, and after setting the gibs, and fixing a few bits and pieces, I am quite happy with the machine. I set up for a cut, lock down all axes but the one I need to move, and my DRO shows that there is virtually no movement (the .000X digit flickers between 1 and 2 as an example). If I have to leave the x and y axes loose, I have adjusted the backlash down as low as I can get them, but take any remaining lash into consideration when making any cuts (just like every other machine I've used), and things turn out pretty well.

I'm sure as I use the machine more, I will find the odd thing here or there that is problematic for me, but as of now I'm quite happy with it .....and look forward to cnc'ing the machine.

I have a bridgemill w/CNC that I bought a couple years back, I planned on doing some prototyping of a mold in AL 6061. I spent more time trying to overcome the shortcomings of the machine, than making chips. The milling motor was typical of many imports, smoked and died. When I addressed this with ST they were quick to disclaim that it was something I did wrong! The bottom line was a defective switch that caused the motor to burn out the start winding. I wasn' t going to waste my time with another import motor and put on a US motor. I bought this machine with ballscrews, this is a must for accuracy with stepper motors. They were modified by ST to fit by cutting off the original leadscrew and welding on the ballscrew, the run out in the screw is unacceptable by any standard, over .030". Also there was .005 " backlash in the ballscrews! The balls were undersized and had to be replaced.
The list goes on and on and my time was too valuable. The one possitive thing I can say is that this machine taught me a lot about accuracy and when I moved on and up into Commercial sized machine my work got easier. If you have the room for a regular size mill, either convert a manual to cnc or find an older cnc that just need a little tlc. I still have this machine in my Basement and havent had the time to dust it off and sell it.

Sealguy I think your expecting way to much.

Many many ballscrews will only hold .004 per foot unless they are precision ground and VERY EXPENSIVE. Shoptask uses the rolled ball screws for the lower costs.

Its not that they are sloppy, its just that they are .004 per foot.

Also milling and placing bearing ends on lead screws are again, several $100 per end and thats x6 for all axis.

In all you are getting an OK deal with some pretty smart workarounds. But by the time you are done putting cash on the barrel head, you are still at $10k for a .004 backlash unit.

Due to its indredibly crappy design I don't go to the shoptask website much... so I don't know what the lastest propeganda is for thier mills.

i have ball screws that shoptask installed. backlash is .008 0n x axis,.011 on
y axis and .003.on z axis. john acts like its my responsibility to get it any lower. i would be happy with .003 per foot, it want come that way. i wont mine getting it lower on my nickle if it were not a brand new machine. another
problem is a binding in the z axis, we are working on that. more to come.(chair)

Norvil1,
When I first got my Bridgemill my backlash was simular to yours. John said that there was some undersize balls that got into some of the Ballscrews. They should measure .125" and when I checked mine they were .1235. I changed them all out and this cut the BL in half. There are several other sources that will add up play and affect your accuracy. Careful placement of a dial indicator and some light levering and you can find where that wasted motion is going. good luck!

I had very poor backlash on the x axis. Acme screws. I discovered the bushing holding the bearings on the right end of the screw where longer than the thickness of the plate they were in. So even with the end play nuts locked down tight, the whole assembly shifted left and right. I removed the bushing and turned it down so it is is shorter than the plate thickness and eliminated this source of error. John said, hmm, they must have made them wrong.

So check end play in your x axis screw.

I haven't measured my final backlash, but it is much better, not great.

Norvil1,
When I first got my Bridgemill my backlash was simular to yours. John said that there was some undersize balls that got into some of the Ballscrews. They should measure .125" and when I checked mine they were .1235. I changed them all out and this cut the BL in half. There are several other sources that will add up play and affect your accuracy. Careful placement of a dial indicator and some light levering and you can find where that wasted motion is going. good luck!

seal guy:
thats the same story he told me. so my thought was, if that is a problem,why did he let it leave that way? if this were a used machine - ok i got no complaint coming, but this a new machine that he charged me 9,987 dollars for. my biggest problem has been the binding in the z axis, without the bevel gears in it is as smooth as oil. fixing the spindle key problem,the burnt up motor wires, and the other problems i fixed is water under the bridge.
i have allready waited 41/2 months and now i have to wait more months to get this thing to cut a part to a reasonable tolorence. my biggest mistake in this whole thing has been to believe jt's claims about this machine, imo
whats claimed is not what is delivered, he' s got my money so he can afford to be calm about the whole thing. if this sounds like a rant, it probable is.
i figured i payed for it, so i can have at least one. end of rant. on the postive side it will cut metal, if anyone really wants a tri-power with all the bells and whistles i can arange for them get one tomorrow instead of the usual 4 to 6 month wait 601-584-8450 8am- 4pm cst.

Norvil1,

You are due your rant. The Lemon law don't apply because we all had the same bad experience. As I said before I moved on from the experience and into some bigger, dedicated machines. Fortunately for me, my Company absorbed the $$ I put into ST.

In hindsight, I paid less for a 10X54 Mill with AC servos, glass scales etc...

At the end of the day I wouldn't recommend to anyone to Buy from ST.

To those who are over coming the problems, my hat is off to you.

Hey guys, I have a Tri-mill and have had most of the same problems as the rest of you. I also have a 1995 Smithy in my garage that was not perfect out of the box either. I stopped a few problems before they started on the Tri-Mill by virtually taking most of the machine apart and cleaning, deburring, and aligning before I even turned it on for the first time. The workmanship is far from great and I must say that the Smithy was a lot better out of the box than the Tri-Mill. The first thing I did was rewire the whole machine with 12 ga. wire and tossed all of that little 18 ga.telephone wire the factory used in the trash. By doing this there is very little resistance and the motors run nice and cool with no lugging or overheating. I had to make new mounting brackets for the X and Y leadscrew gears to take the excessive play out of the gears and clean up the gear teeth on all of the gears to get them to mesh correctly (the workmanship in this area really sucks). I told John at Shoptask that the gears looked like they had been cut out with a hacksaw and a file. The mill spindle gears had a lot of burrs, flashing, and rough cuts in the teeth that had to be cleaned up and that made the spindle operate a lot smoother without binding up. The tool post had the same too high and metric sizing problems and the table slots had to be resized as they were not uniform. John said that he would correct it if I sent the parts back to him but I just did it myself to save the time and the hassle, and to know that they were going to be right when I got done. The list goes on and on. After re-doing everything, the machine is not too bad now; but I don't think that a brand new machine should have to have this much overhauling before it can be used. I have everything except the ball screws from Shoptask on the machine, but have yet to get enough nerve to try the CNC out due to the lack of faith that it will work correctly, or even be close in tolerences. When I do finally have the time to try it, I will do so on something that I don't care about like a piece of cheap wood! Manually though, the mill does quite well now with most metals except that you can't take big bites or it chatters. The lathe is very critical for alignment to cut correctly between centers due to the tailstock being quite sloppy inside of the housing. The Smithy lathe is much better but lacks the power that the Tri-Mill has for deep cuts. All in all it has a lot to offer for the money in a compact design for a hobby or very light industrial use machine. I'll say it is alright and that is about it. I have many different machines and have been a machinist for over 30 years but I would not buy this particular Tri-Mill again unless the quality and workmanship was greatly improved. One other thing, is that it is yellow as advertized, but even that doesn't match on all the pieces.
Single purpose machines are a much better investment if you have the room.
Happy machining,
Badhabits 101

I must say, I'm sure glad I got mine when they were still around $2,000.
The ballscrews were installed before it came for an extra fee.
I had my share of problems from the getgo, but I took it completely apart to get it into my basement. The whole thing was a learning process for me so I didn't gripe TOO much.
Now, because of what I learned, I'd get the basic machine and go from there.
All in all, I'm pretty happy with the whole thing. The lathe/mill concept allowed me to have both. I can hold some pretty tight tolerances by using it correctly!
You may have already seen my thread but here it is anyway:
http://www.cnczone.com/forums/showthread.php?t=2139

...and with it I was able to make this machine....which is very accurate under load, and has good speeds:
http://www.cnczone.com/forums/showthread.php?t=5049

John (bloy)

I will say that John at Shoptask has been very helpful with some of the Tri-Power issues. I am still waiting on the X-Y leadscrew upgrade that he said was done in May'06. This is what January '07 now? and no upgrade sent as yet. I bought the machine in March "06 and I finally got a very limited manual and the warranty paperwork in Dec. "06. I think that his hands seem to be tied on some things due to the factory in China not responding to some of the issues. At least that is what he has relayed to me. My experience with some of the other machine suppliers including Smithy, has been a lot better as far as parts replacement goes. By the way Bloy2004, I really like your CNC Router setup as I do woodworking as well as metal.
I am looking for a better 0.750" - 0.875" left hand thread ball screw for the Tri-Mill as Nook Industries only sells a 0.625" in left hand which is too small. All suggestions are welcome.
Badhabits 101

Yea, I am with BLOY on this one.

I too started with the base machine Eldorado, and upgraded, fixed, repaired, re-designed, overcame ect. But for me it was a learning experience to get into CNC.

It gave me a "cheap" mill/lathe to make my mistakes on.

Knowing what I know now, I would have bought a BP 2, and some dedicated 14" x 40 lathe or something.

But again, if you want to learn to build CNC machines, and stuff, it is a good "School-tool". Not really for commercial use, ok for hobbie use.

Chinese quality control is like saying, "Military Intellegence" they are two mutally exclusive terms.

Scott

I didn't buy this machine to hang my crank on . I bought it to machine parts with.But I need to know what is the thread type of the Z axis lead screw. It measures 5/8 x 16 thread . If its a ACME thread it seem impossible to find.

I had a similar issue on my old Quadra Lift unit, but it was easily solved by changing one belt to a slightly shorter one- Shoptask sent the belt out at no charge.