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  1. #1

    Question Wanhao I3 V1 - Trying to figure out what improved bearings to get and where

    I have a Wanhao i3, it's a V1 model... or close to it. I know that it's not a Version 2, but it seems to be a slightly revised version of the Model 1. It came in two pieces instead of one, and already had the gaskets installed on the Z-axis motors, but many other improvements such as not having the crimped extruder wires out of the drag chain or the fix to the heated bed burning out the main board.

    A few months ago I asked for advice on some upgrades for my printer and metal parts I could use to replace plastic ones, here:

    I got a lot of useful feedback from the replies from there and other boards. Overall, I am definitely going to get the all-metal hotend and extruder parts, and likely get the Z-Braces as well. The only part I am still unsure of is the Carriage Plate.

    I also got some VERY important information about a flaw in the way my heatbed is wired and advice about purchasing a MOSFET module to install into my control box to fix that issue.

    So now, I am mostly set and ready to purchase most of these upgrades and replacements. The only one I am not sure of and still need advice on what parts to purchase is the Bearing Block Mod:

    Namely, I am a little confused on what the terminology of the parts are and which ones to purchase to improve the printer.

    First of all, to make sure I got the terminology right. The cylinder-shaped part is called the linear bearing, and the part it goes into that will screw onto the printer is called the bearing block, right? Though I have sometimes seen the bearing blocks referred to as a pillow block instead.

    I was recommended to replace the linear bearings that the Wanhao comes with (which are model SCS8UU I believe) with longer ones that are model LM8LUU. I couldn't find a good supplier for these however. I saw a few on Amazon, but the reviews were mixed with many complaining about some being defective or off-spec... and the only other place I found was AliExpress...

    I had someone recommend McMaster-Carr:

    Are those overkill? If I am reading the prices right, they seem to be about $16-17 each, and I am confused about the large selection, especially since some of them seem to come with the linear bearings already attached to them. I was also told I might have to "press fit" the linear bearings into the bearing blocks if I got them separate, but I am not sure what that is.

    I was also told about this kit:

    Is it any good in terms of quality? It seems to primarily be designed for a V2 to V2.1 upgrade, but the compatibility states it works on V1 models. I am mainly confused where I can get good quality linear bearings/bearing blocks since many of the places seem to be of low quality, and which ones specifically to get.

    Also, I heard some conflicting reports from some that this will increase my X-axis range, while others claimed it will decrease it. Can anyone confirm either of these? I have a part I want to print that I test-printed before at low settings, and it just BARELY fit within the maximum X and Y margins of my printer. I don't care if it doesn't increase it, I just don't want it to decrease it since then I won't be able to print that part.

    Finally, would there be any point in also replacing the linear bearing/bearing blocks on my Y axis, or no?

  2. #2
    Join Date
    Jul 2017
    You're right on your terminology, the linear bearing is the cylinder with a hole in it to accept the linear rod.
    and the pillow/bearing block (same thing, different name) is the casing around it. Here is one with a bearing already pressed into it, they usually come this way.

    As for the models, the first letters SC or LM tell you if it's a pillow block with a bearing (SC) or just a linear bearing (LM), but beware some suppliers will try to sell you an SC without a bearing so double check. There are also SCJ which let you clamp and 'squoosh' the bearing in the housing to get a 'better' fit, but I recommend against those.
    That there is an SCJ, notice the slit in the side of the housing.
    The next part is the number, 8 tells you they fit an 8mm diameter shaft. Then there is sometimes an L after the 8 which tells you it's a 'long' bearing, double the standard length. Finally the UU refers to the type of seal they have, you should mostly see UUs and those are what you'll need.

    I can't vouch for any suppliers, but my vote is go for some cheap ones off aliexpress and get a couple of extra, you're bound to end up with a set that'll work. As a bonus, you'll have a couple of spares. There is also no point in getting high quality, precision linear bearings to fit onto the cheap linear rods the wanhao came with, you're unlikely to get a better fit than with some cheap chinese bearings. I also wouldn't recommend mcmaster, their prices are quite a bit higher than normal because of their prompt shipping services so unless you need the bearings ASAP, just buy elsewhere.

    Press fitting is 'gently' forcing a linear bearing into the tight fitting pillow/bearing blocks, and I recommend just buying housings with bearings pre installed. It can be difficult to do right and without damaging the bearings when you don't have the right tools, and it's generally not worth the hassle. Most pillow blocks come with bearings anyway.

    Lastly, the reason people fiddle with the x axis bearings is because with the stock configuration, the belt rubs against the bearing/pillow block and causes some wear. Buying a new SC8UU wont help, and won't change your X/Y usable space. The way people fix this is by attacking and taking a chunk out of the casings to make room for the belt. You could do this with a hacksaw or a coarse file. Another alternative is to print new bearing blocks that have room for the belt. No, there isn't really a reason to replace your Y axis bearings as they don't suffer from the same belt rub issues.

    Sorry for the long post, I've gotten into a bad habit. Feel free to give a shout if you have any more questions.

  3. #3
    Yeah, the X-Axis is the main reason I want to change it, but I also have some ringing issues and figured switching from a 3 to 2 pillow block configuration would help, I just can't decide on which blocks to use.

    I am not sure about the "upgrade kit" because the parts seem plastic... buy avoiding the belt-rub seems to be it's primary intention.

  4. #4
    Join Date
    Jul 2017
    Changing the number of pillow blocks wont help with ringing. Ringing is vibration from sudden changes in velocity or direction. If anything taking away a bearing would make it less rigid and make ringing worse.

    Plastic bearing holders are fine, and probably the only ones off the shelf small enough to avoid the belt rub. People go over the top with 3d printers needing metal parts, it's not like they're mills.

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