Ballscrew & Linear Rail Kit - Any Good [Archive]

A_Camera

16-06-2021, 12:28 PM

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-linear-rail-hgr20-1000mm4x-blocksballscrew-rm1605-1000mm-bf12-bk12cnc-set?variant=37919746687175

Looks identical to this kit: https://www.aliexpress.com/item/1005002636582756.html?spm=a2g0o.detail.1000060.1.5 1c652a7clzc4k&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.169870.0&scm_id=1007.13339.169870.0&scm-url=1007.13339.169870.0&pvid=37ab2a02-52f1-4f81-a994-0924217e11aa&_t=gps-id:pcDetailBottomMoreThisSeller,scm-url:1007.13339.169870.0,pvid:37ab2a02-52f1-4f81-a994-0924217e11aa,tpp_buckets:668%230%23131923%230_668% 230%23131923%230_668%23888%233325%232_668%23888%23 3325%232_668%232846%238111%231996_668%235811%23271 91%23100_668%232717%237564%23614_668%231000022185% 231000066058%230_668%233468%2315609%23247_668%2328 46%238111%231996_668%235811%2327191%23100_668%2327 17%237564%23614_668%233164%239976%23722_668%233468 %2315609%23247

Recently I bought a similar kit, but not from the same seller. https://www.aliexpress.com/item/1005002055739903.html?spm=a2g0s.9042311.0.0.47344c 4dvbomq4 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.

WoodKnot

16-06-2021, 12:59 PM

A_Camera

16-06-2021, 02:03 PM

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??

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...

:beer:

Clive S

16-06-2021, 04:51 PM

A_Camera

16-06-2021, 07:41 PM

Have you checked what bearings are in the BK end bearings

...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.

JAZZCNC

16-06-2021, 08:20 PM

...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.

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.

WoodKnot

16-06-2021, 10:11 PM

Kitwn

17-06-2021, 12:10 AM

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 was my point, even the lowest quality rails of this design are going to be way ahead of any cheap, DIY construction that other builders turn to in order to save money. And I certainly hope supported round rails are better as well, that's what I'm using! Though If I'd seen these rails at that price when I built my machine I may well have chosen them instead.

Kit

A_Camera

17-06-2021, 11:50 AM

That was my point, even the lowest quality rails of this design are going to be way ahead of any cheap, DIY construction that other builders turn to in order to save money.

I am glad that I misunderstood your comment before. :cheerful:

And I certainly hope supported round rails are better as well, that's what I'm using!

Same here. Been using those for several years now, initially planned to replace them one day, but gave up the idea because I think they are just fine for my needs. My first CNC was based on unsupported round rods, and while they worked, and even could earn some money using them, I decided to upgrade to supported round rails. The results were satisfying and now, while it would be cool to have these HGR20 rails with HGH20C bearings, I think the work it demands to make the change is not worth it. Yes, these rails are fairly cheap today, but unfortunately it is not a "plug and play" work, but demands a serious modification of every axis. Maybe if something seriously goes wrong with the machine I'll do this as well as fixing the serious issue, but for now I'll be fine.

Though If I'd seen these rails at that price when I built my machine I may well have chosen them instead.

Kit

Yes, I'd definitely chosen these rails if they were as cheap as they are today. As I remember, these were a lot more expensive back in 2013 when I started with mine, and at that time I wasn't even sure that I really wanted a CNC. I just built one for my own mental challenge, to see if I can design, build and learn how to use one, so spending that much on something so totally "useless" thing was just not what I wanted to do. Today it's different. For all newly starters there is a gold mine out there, because really, we have to admit that those cheap Chinese things got a lot better in quality during the last years, so buying cheap is not necessarily the same as buying crap.

:beer:

A_Camera

17-06-2021, 12:47 PM

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

They always come with bearings, one double bearing in the BK and one single in the BF part.

Once you remove the four screws holding the dust cover of the BK12 you will see two bearings. I think the BF12 has a similar (but only one) bearing, but that is the floating end, so it isn't really critical. They are simple 6001Z 28x12x8 bearings.

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These are cheap, but never the less can be very good. 6001Z is one of the most common type, so they are cheap, even if you'd replace them with an SKF or similar. https://www.skf.com/sg/products/rolling-bearings/ball-bearings/deep-groove-ball-bearings/productid-6001-Z

Of course, if you replace them, you might as well replace them with the best ...or not. Replacing 8 BK bearings if you have four screws can cost between 250 - 400 USD (maybe even more), so you must take it as a fairly large cost for an improvement of a hobby machine. There is no need for rushing, it's easy to do even later on, once you have everything up and running.

Never the less, I would not recommend you to start with replacing them, since there is really no reason, unless you really feel some serious issue, or play. I know I can't feel any, so even if some people laugh at them, let them laugh. Replacing is easy, but you need a proper tool, because these are really tight sitting in their seats. Don't use a hammer to get them out because that might damage the seating. There are tools to remove bearings, get one if you not already have one. Anyway, I don't think you will need to replace them unless you really feel there is something wrong with them. When it comes to wear and tear, I don't think you'll ever wear out these cheap bearings. It's a difference if you'd build a professional placing machine with high speed servos running H24/7, but as a hobby machine with slow rotating ball screws you will never come near the performance limit. In fact, inlines and roller skate bearings get a lot more beating than these, after all, these always rotate on smooth surface and at comparably very low speed.

Clive S

17-06-2021, 04:44 PM

They are simple 6001Z 28x12x8 bearings.

But they should be AC bearings back to back to get the preload. This is why I asked him to check !

A_Camera

17-06-2021, 07:28 PM

But they should be AC bearings back to back to get the preload. This is why I asked him to check !

It should not be anything else than what they have specified. If you didn't ask and is not stated then that's it, be happy if the 6001Z is of good quality.

JAZZCNC

17-06-2021, 07:52 PM

Never the less, I would not recommend you to start with replacing them, since there is really no reason, unless you really feel some serious issue, or play. I know I can't feel any, so even if some people laugh at them, let them laugh.

It's not about laughing at people it's about trying to let people know the difference between building the right vs the wrong way. Everything about these is Wrong and pointless for a CNC machine.
They are deliberately made and sold this way to keep the price low to make the kits look cheap with NO regard to whether fit for purpose or not.!

Those bearings in the BK mount are completely wrong for the application as they are not designed for lateral loads, they should have Angular contact bearings, not deep groove bearings like 6001ZZ.
They will wear excessively and they will introduce backlash, even if fit with SKF bearings because they are not designed to operate with lateral loads. Also, to get preload on the bearings and reduce backlash puts extra load on the bearings causing friction which robs power from the motors, again causing extra unnecessary stress on other components like drives, PSU, and lowering performance.

I don't understand why anyone would buy components that are not fit for the purpose, then spend more money on them to put or right and even worse spend money on them replacing bearings with the same inappropriate bearings. Especially when buying correctly the first time isn't that much more expensive and far less hassle.

A_Camera

17-06-2021, 09:00 PM

I quoted the SKF page to show the specs, not that they should be replaced with SKF version of the 6001Z. Of course, if one replaces the bearings one should replace them with better quality AC bearings. To replace 6001Z with similar (but better quality) 6001Z is pointless, or not a good idea.

Anyway, to be honest, I don't think you'd wear out these bearings unless you are a heavy user of the machine. Most hobby users don't run their machines for hours every day, the speed is low (even with fast servos) and is very far from the performance top of those bearings so wearing out will take time. But sure, eventually they may wear out, and in that case they should be replaced, but as I said earlier, replacing is easy and can be done when needed, will result in a few minutes of work per screw, so no big deal.

JAZZCNC

17-06-2021, 09:44 PM

Anyway, to be honest, I don't think you'd wear out these bearings unless you are a heavy user of the machine. Most hobby users don't run their machines for hours every day, the speed is low (even with fast servos) and is very far from the performance top of those bearings so wearing out will take time.

Sorry but your completely wrong on this assumption because there have been many examples here on this forum of people who have bought these BK bearings and even the cheaper BK which did use AC bearings and have had Big problems with backlash caused by excessive wear within the first few months of usage.

I myself had the same issues 12+yrs ago when ball-screws and BK bearings were not commonly available, and not at all on eBay. So buying from China thru aliexpress was the only choice. I myself and many others at that time nearly always had to shim and tweak the bearings and these were AC but low quality and poorly fit, often fit the wrong way around. And I'm sorry to say nothing has changed in this respect with these BK bearings and in fact, I have noticed over the years it's actually got worse.?

To satisfy the demand for cheap kits they started fitting them with deep groove bearings which like I've said above are completely unsuitable for CNC, Esp low spec Machines even more so because they often don't have the excess power to compensate for the excessive friction caused by preloading the bearings enough to eliminate backlash.
It's a catch 22 position.? If you DON'T preload you have backlash, if you DO preload the bearings can not handle the lateral loads and wear excessively. Then throw into the mix the constant checking adjustment to keep backlash out of the machine and it quickly becomes obvious why they are best avoided.

Anyone who thinks differently is just fooling themselves and others.

The 6001ZZ or any other deep grove bearings will easily handle the RPM's but that's not what kills them it's the lateral loads, they are not designed to take lateral loads and virtually all the load on a ball screw is lateral and it's this that kills them quickly.

A_Camera

17-06-2021, 11:21 PM

Clive S

18-06-2021, 07:08 AM

I am not saying that there are no lemons, but that most are OK for hobby use and there is no reason to rush or assume that everything is bad. Of course if one is replacing the bearings one might as well do it right and get the proper ones. But you can't say that just because some people have issues all are having them. In my experience there was a huge quality improvement in these things the last few years, can't compare with how things were like ten years ago. Yes, they do use these simple bearings, but unless it is specified otherwise, there is nothing wrong with that, they didn't fool you. It's not for industrial use, if it was then I'd be more critical about them.

Yes, they do use these simple bearings, but unless it is specified otherwise, there is nothing wrong with that, they didn't fool you. It's not for industrial use, if it was then I'd be more critical about them.

That's the point they were not specified that's why I asked him to check. They are being sold in a kit with rails so should be AC type.

Quote Originally Posted by Clive S View Post
Have you checked what bearings are in the BK end bearings

Originally Posted by A_Camera
...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:

As the op is a beginner he would not know the difference between the bearings so why do you muddy the waters.

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A_Camera

18-06-2021, 09:28 AM

That's the point they were not specified that's why I asked him to check. They are being sold in a kit with rails so should be AC type.

As I made it clear, there is no such thing as "should be" unless it is specified. You can wish for anything, unless it is specified, it's just wishful thinking, and if it is as you wish then it is bonus. The only contract between you and the dealer is that what the specification is saying. That's the way things work. Expectations can be set very high, nobody can stop you from that, but it is naive to believe that something as cheap as these are, are the same in every aspect as the much more expensive ones. The OP is an adult, I am sure the OP understand this as well.

As the op is a beginner he would not know the difference between the bearings

That's why it is important to point out not only the fact that your expectations are too high, but also that there is a set of bearings (the OP did not even expect any) and that those bearings may work for HOBBY use, so there is no reason to hurry changing those, unless he experience issues. Non of that did you or anyone else mentioned. You are so hang up on the AC bearings that that you lost focus from the subject, or target, building a CNC for HOBBY use. Your comment to him:

Have you checked what bearings are in the BK end bearings

...is totally pointless and is what muddying the waters here because it says absolutely NOTHING except ridiculing him for his decision of buying those things. You are not saying ANYTHING about what to expect to see, or which sort you think is the acceptable bearing. NOTHING in that sentence is of any help to the OP or anyone visiting this thread. You didn't even bother to put a question mark after your sentence. The OP did not even expect any bearings in those seats, so the way I see it, any bearing is better than nothing.

In fact, you are so hang up on the AC bearings that you did not mention the most important parts of a ball screw, the screw and the nut. Those can actually cause a much more serious headache than bearings in those seatings. If the screw is bent or damaged there is nothing he can do, other than buying a new. Same for the nut, if something wrong with it and a cleaning does not solve it, then it's a case of biting the bullet and buying a new. Changing the support bearings is peanuts, easy to fix. Never the less, it can be an expensive thing to do for someone on a limited budget, especially if the current ones work well enough. What is "well enough" is not for you (or me) to define. It is up to him, the OP. Now, THAT is help for a newbie starting a new hobby activity. Just saying "Have you checked what bearings are in the BK end bearings" is pointless muddying. It would have been different if you had said more about how things should be according to your opinion, and explained the difference between bearings, but you did NOT do that, not before I chipped in with my opinion, which I have right to express also, without you telling me to shut up.

so why do you muddy the waters.
Are you always this rude or just today and only here? I think you should stop eating barbed wire for breakfast and take a cold shower in the morning.

WoodKnot

18-06-2021, 10:49 AM

m_c

18-06-2021, 12:18 PM

Hi gents

Thank you all for the input and did not expect the response to this thread.

You all talk in riddles to me - as i could talk if i started about my industry sector.

I am not sure if i will be using the end bits with the bearings in, as they might not seat within the aluminium profile?

I thought that's what the end plates are for? or am I getting that wrong?

Most kits that i have looked at spec the bearings separately, so naturally assumed that i would not need those brackets (as per the image posted earlier in the thread)

Hope that makes sense

WoodKnot

The machines you're looking at, are designed to be as cheap as possible to build, and will typically use a couple basic thrust bearings to control screw end float. To be blunt, it's a rubbish method, as thrust bearings are hard to adjust accurately in such a setup, and they provide little to retain the screw co-axially, so once it starts spinning fast, the screw/bearings will start rattling around in each other and the end plates.
The BK bearing blocks should use two angular contact (AC) bearings, which get preloaded (aka you can tighten the nuts up so the bearings are loaded, unlike the before mentioned thrust bearings which would just collapse), and provide co-axial retainment of the screw.

Personally, I'd redesign the machines you're looking at, to make use of BK and BF support bearings (BF is just a basic deep groove bearing to support the screw).
The reason the mentioned machines don't use them, is they add cost. They cost more than a couple basic thrust bearings, and you need additional mounting plates for them.

The issue with cheap BK blocks, is it could be a gamble as to what bearings are fitted, the quality of the bearings, and if they're actually fitted correctly.

JAZZCNC

18-06-2021, 12:51 PM

Ok, I didn't really want to take time out of my day to do this or bash heads with you but this needs to be done for the sake of those we are watching or will see this thread in months or years to come because what you are saying is totally wrong.

I am not saying that there are no lemons, but that most are OK for hobby use and there is no reason to rush or assume that everything is bad. Of course if one is replacing the bearings one might as well do it right and get the proper ones.

It's a simple fact, which if you don't believe me you can go ask SKF or any other bearing manufacturer is that deep groove bearings are completely the wrong bearing for the application these BK bearings are sold for. The whole point of the END fixing is to reduce axial movement and handle the linear forces and to do this then either Thrust bearings or angular contact bearings are the correct choices.

To say otherwise is WRONG and MISLEADING and no amount of arguing over a poor buying decision to save face will change this.

But you can't say that just because some people have issues all are having them.

I didn't say that at all so please don't put words into my mouth.! I said that many on this forum had issues, which is true, and if you had been around long enough you would know this.

In my experience there was a huge quality improvement in these things the last few years, can't compare with how things were like ten years ago. Yes, they do use these simple bearings, but unless it is specified otherwise, there is nothing wrong with that, they didn't fool you. It's not for industrial use, if it was then I'd be more critical about them.

Well, that's exactly the problem here I think.? What experience do you have.? 1 set possibly 2 sets of BK bearings which if they are the same as these how could you know any difference.?
To say "in my experience" should actually mean you have experience of more than a couple of sets and actually experienced the difference between current and old components. If you had the experience then you wouldn't be making desperate face-saving comments like that and know that the current budget BK bearings are indeed worse and unfit for the purpose intended for the reasons I stated above.

You have the right to your opinions and I respect that, but I have the right to point out BULLSHIT when I see it and for the sake of others reading this now and the many 100's or 1000's that will read it in months and years to come I'm calling you out as pedaling BULLSHIT to save face for buying inferior components.

Whether you like it or not, the simple TRUTH is that DEEP GROOVE bearings are wrong for the application of end fixings for ball screws. It's not about AC are the best or the only ones which should be used, far from it, cheaper thrust bearings will work and are correct for the application also but AC is the better type and are what should be fit to the BK type bearings.

It's a simple financial fact that to produce these kits at such stupidly low prices that something must give and it's 99.9% nailed on most will come with DEEP Groove bearings for this very reason.

Now back to work.!

A_Camera

18-06-2021, 01:13 PM

Hi gents

I am not sure if i will be using the end bits with the bearings in, as they might not seat within the aluminium profile?
The 1605 BK/BF bearing holders fit exactly (but not perfectly) into the 45 mm gaps of 45x90 extrusions if you want to install them across in two T-nut tracks using 6 mm screws, but you must consider the ball nut because that will need some spacer or other solution, due to the fact that the HGR20 + HGH20 is 30mm high while the ball nut flange demands 45mm...

30089

...or 50mm if it is turned 90° high from the bottom.

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You can solve that in many ways, but it must be solved somehow. I think you will see that more clearly once you get the stuff. It's easier when you have something in front of you to look at than just CAD drawings or words.

A_Camera

18-06-2021, 01:27 PM

Relax Jazz, I am not exactly disagreeing about the differences with you or others, but as you say, it's about costs, so it is a compromise.

Regarding experience, I should actually ask the same... because honestly, if you have such low views on those BK/BF bearings then I have to assume that you don't use them. On the other hand, I am waiting for the 10th, so yes, I must claim that I have some experience with them, more than you think. OK, only for 1605 and 1204 screws, but none the less... I was not born yesterday just because I ask some questions occasionally.

Anyway, I am NOT saying that those bearings are as good as AC bearings. What made you believe that? All I am saying is that he should wait and see and decide on his own for the final decision. Of course it's good that the alternatives are clear and drawbacks are highlighted, but as been said before, replacing the bearings is easy and can wait. But then again, if replacing means complete redesign of bearing seats to fit AC bearings then it is a huge job for an amateur and also a large one for a pro. It's also a hobby machine, so aiming for something reachable is better than aiming at the stars and never get there.

WoodKnot

18-06-2021, 02:04 PM

The 1605 BK/BF bearing holders fit exactly (but not perfectly) into the 45 mm gaps of 45x90 extrusions if you want to install them across in two T-nut tracks using 6 mm screws, but you must consider the ball nut because that will need some spacer or other solution, due to the fact that the HGR20 + HGH20 is 30mm high while the ball nut flange demands 45mm...

30089

...or 50mm if it is turned 90° high from the bottom.

30090

You can solve that in many ways, but it must be solved somehow. I think you will see that more clearly once you get the stuff. It's easier when you have something in front of you to look at than just CAD drawings or words.

Thanks A Camera

I had noticed that all the converted ones that i had viewed that they had to create some sort of spacer block, but yes, i was waiting for the arrival of the parts, i think holistically first, so then have to work backwards to get all the joined up bits to work.

So i see what i want to achieve and how the look is perceived in my minds eye, then have to work backwards to achieve what i am seeing.

My issue is that i don't work to plans and do everything 'off the cuff' sort of speak, which can be a bit problematic!

WoodKnot

WoodKnot

18-06-2021, 02:26 PM

Hi A Camera

Just been on your channel - cant believe you actually CNC in your house?

That's what it looks like!

Like the actuators, totally wicked idea - i just use the mechanical leverage style ones in the workshop.

I also hope that you are not going to use that tablesaw in your house - that will make a mess!

WoodKnot

JAZZCNC

18-06-2021, 07:39 PM

Relax Jazz, I am not exactly disagreeing about the differences with you or others, but as you say, it's about costs, so it is a compromise.

I'm 100% relaxed Camera but this isn't about costs at all, it's about what is suitable and what's not and those BK bearings with deep groove bearings are not suitable for a CNC machine because they are not designed to handle the loads in an axial direction. It completely defeats the point of fitting ball-screws if the end fixings are allowing the screw to float which they will with these deep grove bearings unless they are highly preloaded and it's this high preloading they are not designed to handle so they quickly wear excessively which in turn put stress on other parts of the machine. It quickly becomes a vicious circle of wear and stickiness.!

Regarding experience, I should actually ask the same... because honestly, if you have such low views on those BK/BF bearings then I have to assume that you don't use them. On the other hand, I am waiting for the 10th, so yes, I must claim that I have some experience with them, more than you think. OK, only for 1605 and 1204 screws, but none the less... I was not born yesterday just because I ask some questions occasionally.

You are correct that I don't use these and never would, but I do have lots of experience of replacing them and helping other people who have unwittingly bought these, and the number is far more than your measly ten.!
In terms of experience fitting BK/BF bearings in general then I buy them by the 100 and just today I've fit 8 sets so you could say I know a little about them.!!

Anyway, I am NOT saying that those bearings are as good as AC bearings. What made you believe that? All I am saying is that he should wait and see and decide on his own for the final decision. Of course it's good that the alternatives are clear and drawbacks are highlighted, but as been said before, replacing the bearings is easy and can wait. But then again, if replacing means complete redesign of bearing seats to fit AC bearings then it is a huge job for an amateur and also a large one for a pro. It's also a hobby machine, so aiming for something reachable is better than aiming at the stars and never get there.

First of all, I didn't think you thought they were as good and never implied that you did. My objection to your comments is solely based on the fact that you advised the OP and advocate to others the use of Deep grove bearings for BK bearings was perfectly fine, they are NOT.

The other thing I don't agree with or understand is why anyone would buy these knowing they are poor quality or in this case plainly wrong and pay again to make good.? Crazy to me when for not much more you can buy the correct BK bearings.

On another note, I also feel you owe Clive S an apology because his comment was a valid one, even if it was short and to the point, your attack on him personally was unjustified and out of order in my opinion.!..:thumbdown:

A_Camera

23-06-2021, 12:59 PM

Hi A Camera

Just been on your channel - cant believe you actually CNC in your house?

That's what it looks like!

Yes, you seen it right. I have a fairly large room, which is a home office / hobby room / software, firmware and electronic development center, photo studio, as well as other hobby activity room. My CNC and my two 3D printers are used in this room as well. However, I NEVER use any liquids to cool and lubricate, I print only PLA and PETG, my spindle is air cooled, my CNC is covered around and I use a dust shoe when milling PCB and most other things. I don't mill any wood. Anyway, this solution suits me well.

Like the actuators, totally wicked idea - i just use the mechanical leverage style ones in the workshop.

Thanks. I made that mod a few months ago. Got tired of the primitive method I used before when I had to move my CNC. It is just soooooo much easier this way. Now I can easily clean behind the CNC or make any sort of modification / improvement or whatever which may demand moving the machine.

I also hope that you are not going to use that tablesaw in your house - that will make a mess!

WoodKnot

That was only opened, unpacked and "dry" run for a minute in the house. It lives in the actual workshop / storage are (a separate building) where other machines and tools are.

A_Camera

23-06-2021, 01:30 PM

On another note, I also feel you owe Clive S an apology because his comment was a valid one, even if it was short and to the point, your attack on him personally was unjustified and out of order in my opinion.!..:thumbdown:

You have your right to have any opinion, but I reserve my rights to disagree with that opinion. I was NOT the one who addressed him in a rude manner, I simply turned the mirror towards him and used the same language. :thumbdown:

WoodKnot

23-06-2021, 01:48 PM

WoodKnot

23-06-2021, 01:56 PM

How do you get that text box when responding to just part of someone's comments?

Just tried it and it did not work?

Thanks

WoodKnot

A_Camera

23-06-2021, 06:40 PM

How do you get that text box when responding to just part of someone's comments?

Just tried it and it did not work?

Thanks

WoodKnot

Click Reply With Quote
Copy the bracketed text "QUOTE=" and paste at the beginning you want quote.
Copy the bracketed text "/QUOTE" (the last one) and paste at the end you want quote.

You can also split the post that way, or edit if you want to, like the message above, where the finishing quote in brackets and is missing.

A_Camera

23-06-2021, 06:59 PM

Just had to read up on PLA - I am in the recycling industry and i have never heard of it - so its a biopolymer, but not a commodity polymer.

Looks like it composts well!

What do use it for? Is it brittle, it does not sound like a flexible polymer?

WoodKnot

There are many qualities. I try to buy good quality (not necessarily cheap), made in Europe PLA. Yes, it is recyclable and the fumes are non-toxic, so I don't need to take any special precautions, or venting. PLA is the most commonly used plastic for 3D printing and is environment friendly, I think it is made using corn as main ingredient, but I am not 100% about it. Not that flexible but also, if good quality and printed right it can be used for many years in different indoor environment. I use it for everything possible, and have been using for many years now. So far no parts had to be thrown away because of age. I also make some parts which are used on cameras and are parts of what I am selling globally. So far, nobody complained, so it seems to work everywhere between Australia and northern Canada, so I am happy using it. My printer is running almost every day, even at this moment.

A_Camera

23-06-2021, 07:19 PM

Thanks A Camera

You're welcome.

I had noticed that all the converted ones that i had viewed that they had to create some sort of spacer block, but yes, i was waiting for the arrival of the parts, i think holistically first, so then have to work backwards to get all the joined up bits to work.

Yes, some sort of spacing or other solution is necessary. It is definitely easier to figure out a solution once you have them in front of you, especially if you are not used to read mechanical drawings, but also if you are open to changes and can divert from your own design.

So i see what i want to achieve and how the look is perceived in my minds eye, then have to work backwards to achieve what i am seeing.

My issue is that i don't work to plans and do everything 'off the cuff' sort of speak, which can be a bit problematic!

WoodKnot

I also don't spend hours and weeks in front of a computer to CAD a machine. I think that's a lot of wasted time, unless you want to reproduce and sell those things. Every new machine is a prototype. I make sketches using good old pencil and paper, but even those are free hand sketches, rarely use a ruler for drawing. It's enough for me to have the design sketched and the details in my head. Of course, this results in a few extra holes, but so what...

Anyway, I received this today:

30107

So far so good. What's funny is that the kit included four carriages. I have no idea how they are thinking... 200mm rails and four of those means basically no movement at all or maximum 46mm. I knew this when I ordered, I only need one on each rail, but this was the best price, so now I have two spares. BTW, even this BK feels fine to me, and I still think it is best to leave it as it is and replace the bearings with AC once these are worn out, if they ever will before I die or stop using it.

WoodKnot

23-06-2021, 10:36 PM

So far so good. What's funny is that the kit included four carriages. I have no idea how they are thinking... 200mm rails and four of those means basically no movement at all or maximum 46mm. I knew this when I ordered, I only need one on each rail, but this was the best price, so now I have two spares. BTW, even this BK feels fine to me, and I still think it is best to leave it as it is and replace the bearings with AC once these are worn out, if they ever will before I die or stop using it.

They suggest 250mm but went for the stock 300mm, I suppose better to have greater travel then less?

A_Camera

24-06-2021, 07:00 AM

They suggest 250mm but went for the stock 300mm, I suppose better to have greater travel then less?

This is a kit with 250mm ballscrew and 200mm rails. I need about 80mm motion that's why I chose this kit.

WoodKnot

24-06-2021, 11:22 AM

This is a kit with 250mm ballscrew and 200mm rails. I need about 80mm motion that's why I chose this kit.

I presume A Camera that you can just set the limit switches on the Z axis to reduce the amount of required travel anyway

A_Camera

24-06-2021, 02:13 PM

I presume A Camera that you can just set the limit switches on the Z axis to reduce the amount of required travel anyway

This is for my micro lathe experimental project (https://youtu.be/g8rXwJtne38) and will be used as X axis. It's an experiment only, but movement is short since the chuck is only 100mm, so I figure 80mm is enough. I will never need to make anything with 160mm diameter anyway. Initially it won't have any steppers on the axes, so no need for limit switch. My CNC Z has limit switches but only the upper one is ever triggered. That is different, there I have 160mm Z clearance and 140mm movement, so it is much larger and wider than this is going to be.

tonyfoale

06-09-2021, 06:25 PM

I just came across this thread and thought that some of my adventures with ball screws, bearing mounting blocks, and making ball nuts fit where they shouldn't might be of interest.
https://www.homemadetools.net/forum/lathe-cross-slide-conversion-ball-screw-83598#post174256

BeagleBrainz

07-09-2021, 06:36 AM

I saw the video on YouTube a week or 2 ago. Very impressed.

m.marino

22-09-2021, 11:06 AM

[QUOTE=A_Camera;125518]Yes, you seen it right. I have a fairly large room, which is a home office / hobby room / software, firmware and electronic development center, photo studio, as well as other hobby activity room. My CNC and my two 3D printers are used in this room as well. However, I NEVER use any liquids to cool and lubricate, I print only PLA and PETG, my spindle is air cooled, my CNC is covered around and I use a dust shoe when milling PCB and most other things. I don't mill any wood. Anyway, this solution suits me well.

Just had to read up on PLA - I am in the recycling industry and i have never heard of it - so its a biopolymer, but not a commodity polymer.

Looks like it composts well!

What do use it for? Is it brittle, it does not sound like a flexible polymer?

WoodKnot

PLA as mentioned is a very common filament used in FDM/FFM 3D printing of plastics. While the numbers look very good for biodegradability it actually requires specialized enezyme to get the best results. Other wise it is rather slow in degrading (think oak leaves and other durable starches. Depending on what is added to it can be rather strong and can be post processed with heat to cause further interlayer bonding as well as increase cross linakges of the polymers. Not UV stable but does have a rather slow UV degradation (Longer than Polypropylene plastics). Can be solvent smoothed with certain chemicals and as such is less tolerant than say the PET/CPE family. Can be made food safe.

Hope that gives a few better ideas on it. Used heavily in the miniature and modeling community as it is one of the cheapest filaments in the industry. Not considered an engineering material though.

Also having been one of those folks who bought a machine that did NOT use proper bearings (or even blocks to be honest). I can tell you the headaches from chasing down chatter, flex, runout and a mess of other issues is not something I would wish on anyone. That was a long time ago and I have a much better machine now that needs some servicing and new ballscrews on the X axis. That and doing some work preparing hopefully to move to the US.