Thread: Linear Rails & Blocks

I bought my rails and blocks from Chai, also ballscrews and spindle and VFD. Apart from a few minor packaging problems with the spindles I have not really identified any major discontent with this seller from the comments of many of this forum who have bought from him. Certainly his prices are miles ahead of anything locally.

My 2 cents worth!

Cheers,

Alan.

Everything that I have purchased from Chai has been all good approx 1k of gear.

No worries from myself either. Bought screws, rails and spindle with VFD
cheers
rosco

Hi Simon

Bought all my gear (rails, bearing blocks, ballscrews, couplings) from Chai. Its all good, and he is fairly easy to communicate with too. Price wise, he can't be beaten. Reliable too.

If he hasn't got exactly what you want listed on ebay, just send him an email and he will arrange it for you. His email is: guixuan chai [[email protected]]

Cheers
Geoff

Great and trustworthy bloke,

Just keep the rails under a meter (I think he can get away with 1200mm) because I had mine couriered in and it cost me ~400USD for 2x 2500, 2x1200 + a bunch of other stuff.

He has the best price, you wont find anything close to it in australia, and anyone else selling overseas wont be able to do much better if at all.


BTW hope to see a new build thread I havnt seen a new one for some time now.

Thanks for the comments thus far.

Looks like the supplier and quality are both good.

My concern now is whether 16mm rails are up to the task, or whether 20mm or 25mm would be the go.

The larger units are more expensive, I am trying to contain costs, and they weigh more so I supose that could be an issue as far as inertia or what ever.

I bought the hobbyCNC stepper kit (305oz) when the A$ was at its strongest so that is what I am dealing with torque wise. To begin with, I plan to use allthread (or ACME) to then decide on whether to upgrade the screws.

Do you guys think I will be OK with the 16mm units?

Simon

Simon,
I have used 16mm and because they are fully supported I think they are as stiff as you could want them. My table is 1500 x 900 and whilst it is not yet working, I can't see why they won't be brilliant when it is all up and running. I have finished all of my axies and until I put my Y & Z ball screws I was having great fun sending the gantry around the table with minimal effort. It was my show off trick when anyone came to visit. I still haven't got my r&p going on the X axis so can still show off that axis. With my gantry weighing about 10 tonne (well it is very solid anyway!) it runs very smoothly and with little effort.
If you are looking for a 'moderate cost' option, 16mm is the way to go.

Cheers,

Alan

16 or 20mm will do fine, I wouldnt go with 25mm its seriously overkill.

BTW if you want different lengths to what he has ask him as he can cut to any length.

Hi Simon,
Good to have a build on the way.

Ridgidiity is more than just rails so as long as your structure is solid then 16 or 20 will be fine. Rails are the rolling element and do not give structural strength and particulary so with the round rails.

The 25's trucks have more ball tracks and are longer therefore they have greater surface contact with the rails and can handle higher loads. The loads I am talking about are much higher than a machine size you are proposing so go the smaller size and save a few bucks. For those interested 25 open trucks have 5 ball tracks and 20 mm have 4.

If you haven't got your acme screws then price them and compare that price to the Chinese ballscrews - I think you will be pleasantly surprised. There is a big difference between acme and ballscrews in regard to tolerance and friction so the decision is easy if the prices compare favourably. If you have the acme screws then run those as they will work and give you a reasonable result.

Hi, good to have so much help from you guys.

I have checked out the ballscrews and the ball screws are not that expensive as you say. Would using the RM1605, 16mm diamter, 5mm? lead be OK for an X-Y of about 500-600mm by about 1000-1200mm? or would another from the attached table be better?

Also is it best to get the ends machined by the supplier. I have a lathe and mill and am wondering if I could machine the ends myself, or is it too much stuffing around as the screws would be hardened?

Regards

Simon

The 16mm by 5 pitch are fine for the smaller axis and borderline for the longer axis. If you stick with 1000mm then fine but if you go 1200mm they are borderline. They will work but better to have 20mm at 1200mm length. Seeing you only have a 305oz motor then maybe stick with the 16mm for the 1200 length.

I used to machine the ends of the screws myself but would break about two to three tips of my Chinese carbide inserts on each end as the screw is case hardened and it is an interupted cut. His machining prices are so cheap I now get him to do it.

You don't have to stick with the sizes he lists on ebay so don't be limited by the listings.

Thanks Rod

Looks like I am locking in with the 16mm ball screws as well as the rails.

Regarding the machining of the ball screws' ends, do I just ask for the supplier to provide the screws with machined ends or do I need to specify exactly how I want them machined? If I need to specify, what do I ask for?

Also, he has the couplers and I suppose that his prices are also competitive, so I mose well get those off him as well?

I can machine up the end plates for the ball screws' bearings, so I will be OK for those.

Anything else that I may need off him?

Thanks

Simon

P.S. It will probaly be a month or so before I can get underway, but I will be sure to start a thread for the build.

Hi Simon,
Yes get the helical couplers. You will need to supply a drawing so do this before ordering the screws. I just sent a Jpeg sketch with the dimensions on it and it was OK.
Draw the ends to fit the bearing supports you will make. Basically the end turned down to the inside bearing size, then a threaded portion for a nut to lock it on and then an extended bit to clamp the helical coupling. Use an angular contact bearing so you do not get end play. The other end is just turned down to your rear bearing size and the bearing floats on the shaft.

If you want info on the bearing and where to get them cheap and also a copy of my sketch send me you email address.

Look forward to seeing your build.

Rod

Thanks for the tips, PM sent

Simon