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15-06-2021 #1
Hi all
Found these kits - was think of using a pair on all 3 axis - mines going to be hobbyist build!! - what are your thoughts
Link https://vevor.co.uk/products/2x-line...37919746687175Last edited by WoodKnot; 15-06-2021 at 01:40 PM.
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15-06-2021 #2
Well, they're certainly cheap, but if you're on a tight budget they'll be better than the skate bearing and angle-iron alternative that many people turn to. As you say, it's a hobbyist build so presumably isn't going to be running 24/7. You could always buy one set and check the quality before committing to all 3, the delivery time isn't too bad by the look of it.
KitAn optimist says the glass is half full, a pessimist says the glass is half empty, an engineer says you're using the wrong sized glass.
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16-06-2021 #3
Thanks Kitwin - I will give them a go
Steve
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16-06-2021 #4
Looks identical to this kit: https://www.aliexpress.com/item/1005...%2315609%23247
Recently I bought a similar kit, but not from the same seller. https://www.aliexpress.com/item/1005...47344c4dvbomq4 I only needed 400mm long, and I must say that what I received is excellent, I am very happy with it.
I try to avoid sellers with such low rate as 94%, but your stuff can be equally good as mine. 1000mm is pretty long, so it is more critical, but otherwise I think it should be fine. Mine are good quality. Kitwin is a bit negative... unless there is a manufacturing defect, to say that they are "better than the skate bearing and angle-iron alternative" is really nonsense. Of course they are better, even supported round bars are better, MUCH better. You can't compare with those under the same sun.
That said, you should be prepared to clean the bearings. They can come dirty from the factory, but cleaning those linear slides is really no big deal. Generally, I think that good cleaning is always necessary, though these last ones I bought seems very nice and clean. All my bearings came individually packed, nice in sealed plastic bags, as well as all the other things, everything individually packed. I don't know if yours will be the same.Last edited by A_Camera; 16-06-2021 at 01:34 PM.
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16-06-2021 #5
Thanks A Camera -
Ok, they are not a top brand and of course, for the price, it does make you question it. Like most stuff these days, it comes out of the same factories but with a different brand name. I am going start buying bits and pieces over the next few weeks to at least get he base machine built - still struggling on how the hell i am going to get my plates made with no cad ability??
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16-06-2021 #6
True that (normally) you get what you pay for, but in this case, I think that if I'd spent 5-10 times more, I'd NOT get 5-10 times better stuff. I bought similar stuff before and this last buy is definitely miles ahead in quality. Last time (before this one) I had to open every bearing and clean each ball and everything because there was so much grit in them that they were grinding the rails and the balls. It was no fun with all those tiny balls in 16 bearings... but I managed without losing a single one. So the way I see it, that's the worst that can happen. Of course, a bent screw or rail is even worse, but I thing that's rare. Also, even if you had bad luck and received a bent screw, it is so cheap that you can buy a new one. In fact, you can buy several before you are up in the same price as the real high quality ones.
So far I bought in total 8 ball screws (1204 and 1605) but never had any issues. But, as I said, all mine are shorter, the longest 1605 I bought is 650mm, so not very far from your 1000mm, but still shorter. One thing you should carefully consider is the travel distance and speed. With 1605 you need many turns from one end to the other, so you will need a lot of time, or very fast and powerful servo or stepper motors.
Regarding no CAD-ability... I designed and built my CNC without CAD, just paper, pen and calculator. I never had the patience to spend a lot of time on fancy 3D CAD models. I understand when people work with that professionally and selling the machines or models, but for a one single machine, what's the point...? In fact, many things I made are made with manual G-code programming without any CAD. Some times I use simple 2D CAD and convert the DXF file to G-code, edit and correct or change manually the things needed to be changed. Among the tools I am using there is an old CAD software I bought about 20 years ago for about 20USD. That is my favourite for many jobs. After that comes FreeCAD, which is a free (donateware) but extremely professional and advanced CAD software. I use that mostly for 3D printed objects. That software I am so happy with, that every time there is an update I pay a sum (I think 20USD) because I consider those guys worth the money. But I never done any machine modelling. I just build them...
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16-06-2021 #8
...for that price...? I mean, seriously, if the bearings are crap you buy some SKF quality bearings and replace them. It's a 5 minute job. Mine are so far perfectly OK. I just bought another kit. This one:
https://www.ebay.com/itm/393113635297
Will get it by next week and I expect it to be as good as the previous ones, which I bought on Aliexpress and not from the same seller.
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16-06-2021 #9
Not a fair comment really because Clive S makes a valid point.? Many of these kits will and do come with standard deep grove bearings which are completely unsuitable for CNC or at best they use cheap nasty angular contact bearings which need constant adjustment and wear out within months.
Many many people have bought them only to find this out after the machine is built when they are chasing chatter or error from backlash etc.
SKF Angular contact bearings will cost £20 to £30 per pair and for the same amount or not much more you can buy much higher quality C5 BK bearings from Fred at BST. These are light years different in quality and will last years. So sometimes it's false economy to buy too cheap.
I agree these kits are light years better than threaded rod etc and are a great way to get started building a CNC machine provided you don't expect top quality and accept they will wear out and become sloppy quickly if not maintained and cleaned on a very regular basis. They won't tolerate harsh conditions very well either.-use common sense, if you lack it, there is no software to help that.
Email: [email protected]
Web site: www.jazzcnc.co.uk
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16-06-2021 #10
Thanks for the advice on the bearings!
I was not sure if they even came with bearings?
I will take an image if there is any kind of stamp on them.
Presume I just take internal and external measurements and order the replacements
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