Anyone heard of "Three-Ring Precision Machinery"? (Profile Rails)

Hi all,

Ive been in the market to upgrade linear rails, and with my budget I knew that I would either need to go with Hiwins or get the lucky eBay scores.

While looking around for different Hiwin prices, I came accross a company selling profile rail and blocks called "Three-Ring Precision Machinery." The prices that they have are very low for their items, and from the only supplier that I have found of this company the shipping isn't outrageously gouged either.

Blocks for their "15" series rails are about $13 US per piece, and shipping is about $7 US for the first and an additional two or three dollars per additional.

The rail has ridiculous prices as well. About $50 US for a 1600mm piece of "15" series, shipping was $50 for the first and $30 per additional.

They have profile rails in all sizes from 15 to 45, and the prices are universally cheaper throughout the store.

I can not find one bit of information about these rails though. Google has failed me, and the only thing that comes up from Google or here are posts making references to three ring binders. I do not expect these rails to be top of the line quality or anything, but at this price, they are more economical than those SBR series supported shaft rails, but with the advantage of the block being able to take forces in all directions. Are these worth anything at all, or would it be better to just stick with the Hiwins?

Im not sure if posting a direct link is allowed on the forums, but here is the store on Aliexpress: Yueqing Three-Ring Precision Machinery Co.,Ltd - Small Orders Online Store, Hot Selling rail tool,rail weaver,rail clothes and more on Aliexpress.com | Alibaba Group

Wow those are good prices. Not sure of the quality but I have a laser cutter in design and may need to try these out. May be perfect for that.


Steve

Wow is right.
$370 for a pair of 20mm rails 3000mm long. :eek:

I recently paid about $600 for a pair of the same size surplus Hiwin rails.

The price is what makes me a little worried. I do not expect them to be an extreme quality at that price, but it creates a very good alternative.

They claim that their 15, 25, and 45 are Hiwin compatable, and that the 20, 25, 30, 35 are THK compatable, which I would imagine would apply to both rails and blocks.

Even if their precision is sub-par of a standard profile rail, it still would beat out the weaknesses of supported shafts, as well as V-Wheels.

I am also skeptical to trust their precision rating, since there are numerous known Chinese outlets that are known to be very "relaxed" in their rating requirements compared to the rest of the world.

If anyone can find any information of this company, I would not only be very shocked, but also very grateful.

For genuine Hiwin, BST Automation on aliexpress are good.

Seelesturm

They seem to be honest, they say the general accuracy is .1mm thats .004" not much use for a machine, but there precision series .01mm or .00039" that would be good for machine use, so work out the cost on .01mm accuracy, with a medium preload

If I was going to buy them and take a chance, I would first order something for a Z axis. :) Nice find though. It take ages waiting on Ebay for the exact rails that I need. I have been lucky a few times though and got brand new THK 25's for less than this company offers. Tose deals are few and far between though.

I decided to get a set of these and see what they look like. At almost 1/3 the cost it was hard to pass up. Will report back once I have them in hand and check them out.


Steve

Very interested in these as well. Subscribed

Quick update.
Order was placed on Tuesday 1/20
Order shipped Friday 1/23

Due to arrive by 1/30

Shipping was quicker than I expected. I had heard Aliexpress ordering took longer to ship.


Steve

The package arrived today.
Packaging could have been better. They really need to have something to prevent bending the rails most people package with wood slats.
They did include the hole plugs for the rails which was a bonus. But they had them in an un-sealed bag so they were loose everywhere in the "box".
I put a car on a rail and it feels pretty good, no noticeable play and moves smoothly.
The 1500mm rail has me worried though as it has about .075 bow top to bottom. Not positive it will straighten out when I bolt it to an extrusion.
I will take a set to the lab at work and do some measurements on actual play with loads and check the dimensions hardness etc...
Attachment 266442
Attachment 266444
Attachment 266446
Attachment 266450


Steve

I don't think you have to worry about a bow in the rails, they should conform to whatever you bolt them to. I'd be suprised if the extrusion had less than 0.075" of variation over 60"

Quote:

---

Originally Posted by Spk64

The package arrived today.
Packaging could have been better. They really need to have something to prevent bending the rails most people package with wood slats.
They did include the hole plugs for the rails which was a bonus. But they had them in an un-sealed bag so they were loose everywhere in the "box".
I put a car on a rail and it feels pretty good, no noticeable play and moves smoothly.
The 1500mm rail has me worried though as it has about .075 bow top to bottom. Not positive it will straighten out when I bolt it to an extrusion.
I will take a set to the lab at work and do some measurements on actual play with loads and check the dimensions hardness etc...
Attachment 266442
Attachment 266444
Attachment 266446
Attachment 266450


Steve

---

If you get Misumi heavy-duty extrusion you can order it milled flat on 2 (opposing) faces; being their side walls are about 6mm you should have a pretty decent surface to bolt to. I'd probably use a pre-drilled full length t-bar in lieu of t-nuts.

Louie
Yes, on my CNC router I did order the blank t nuts and drilled the pattern in it.
I am now working on a laser cutter with smaller extrusions. Original plan was to use the long blank t nuts again but I found some M4 t nuts really cheap so going to go that route on this build.
I did bolt the rail on to the extrusion and it seemed to pull flat but i think it also pulled the extrusion slightly. I will check it closer when I get further along on the build.


Steve

Did a some testing today on the new rails and cars.
I suspected the rails may not have been heat treated to the same specs as a THK rail.
Rails had lots of nicks and dings from the improper packaging. Mostly in non-critical areas but hardened steel should not have the dents visible like I have seen.
Tested the CHTR rails and they were only 38 RC.
Attachment 266598
Tested the CHTR Car and it was 58-60 RC .
Attachment 266600

Tested a THK rail and it was 62 RC.
Attachment 266602

Being only 38 RC I expect these rails will see quick wear if loads are applied on a regular basis.


Tomorrow I may do the load testing to see how much deflection the cars have.

Did some load testing today.
1. With Rail clamped in place and a 20 pound load applied 75mm off center inline with rail.
- .002 Deflection with 20 pound load
2. With Rail Clamped in place and a 20 pound load applied 60mm off the side of the rail.
- .002-.003 Deflection with same 20 pound load

In a normal setup with dual rails and 2 cars per rail they should perform well.
The only down side I noticed with the rails is the lack of hardness. So premature wear may be the only issue to deal with if loads are high.

Steve

Spk64

As for your hardness, you need 12 to 16 points difference between the 2 parts, or you will get galling, that is why you have one hard part & one not so hard, smoothness of the ground surface is more important

Was the Deflection with the rail mounted on the extrusion, so the extrusion if moving, is not supporting the rail very well

Rail was mounted rigid on Dillion Force gage. Defelction was all in the car.

Ground finish was not near the quality of the THK. Much rougher finish.

If cost was no object THK would be my car\rail of choice. We use and abuse these by the hundreds at work. They last for ever and rarely wear out.

I suspect one of these rails would not last a week in some of our equipment without seeing some heavy wear tracks in the soft rails.

For a hobby machine with lighter use and lighter loads these CHTR cars and rails should work fine. Beyond that would be a stretch.

Spk64

That's good feedback, it gives others a good idea of what they are getting, still sounds much better than the round rails

Did you get the Precision Rails, or regular General purpose

I really have no idea what version I received. The paperwork and part numbers never made much sense. Guessing just general.

And yes these would be better than any round rail system.