[yukonho]

Another question there are options for "floating" bearings, in Y or Z axis. I am not clear on this.Any insight?
co

[mhackney]

yukonho - I used the Drylin 27. If you look at the specs, they should be plenty for my application. I have chatted with a few others here and over at rcgroups that have used these bearings successfully on larger machines. There were some complaints about mounting the sliders but I didn't really have a problem with that. A drill press with a fence helped a lot though to align the holes.

I also talked to an app engineer on the phone to verify. He also told me about the floating bearings but I decided to go with the standard bearings on both rails (2 bearings each). The floating bearings are slightly undersized (.002" I recall) so that you do not need to align the rail they ride on as precisely. Basically, you put the 2 standard bearings on 1 rail, install and align it, then put the 2 floaters on the other rail and install it. The appp engineer told me that all of the data they colllected was in a 2 rail configuration with the standard bearings. Given that THK and others all use non-floating bearings I decided to go that route. I have installed my X rails (photos later) and it realy was not difficult at all to align them.

On the Z, I especially wanted the rigidity of the non-floating bearings.


michael

[yukonho]

That is good news, the 27's are cheaper. Thanks for all the info. I didn't find all the specs on the website, I will look again.
Looks like I might go with these instead of the rollerblade bearings because they are much easier. A few bolts and they are in, no drilling, bolting, aligning, re-aligning......
Looking forward to the pictures.
co

[yukonho]

One more question. Did you use the carriages with mounting bolts or without? Which wouls you recommend?
co

[vacpress]

mhackney,

I am looking at the same IGUS N27? linear rail to build a small 5 axis machine. I Like the 1.00/in rail cost and the $5 bearing cost.. Plus I got 4 of the N27 bearings at the recent Manufacturing Show in chicago. I am also very curiosu to see how this goes. I would be working on a much different style of machine.. Smaller work envelope, but more complex. Ive got a preliminary design in Solidworks, and have decided to wait for your input.. Did you get the bearings with the built-in bolt-holes? Did you price the meatier stuff like the 80mm rail? The IGUS rep I spent 20minutes talking to seemed very interested in the idea that people might use the lighter rail in small inexpensive CNC. I even mentioned the possibility of OEM IGUS bearings in extruded parts might be able to greatly reduce the cost of current machines into the $200-500 range.. We even talked about CNC machines being sold at Home Depot that work like a printer...

How much rail and how many bearings are you using?

Any word on what your total purchase was like? Roughy?

Thanks!

[mhackney]

yukonho - go to http://igus.bdol.com/show_dn.asp and download the PDF Catalog for Drylin 27. It has all the specs in it.

[mhackney]

yukonho - I used the carriages without the mounting bolts. I'll take a photo and post tomorrow. basically, these just have a recessed hole and a bolt inserts up from underneath the carriage to attach it to the table or platform. the version with the mounting bolts has a bolt attached (how I am not sure). I know others had used the ones I used and they seem like a good way to do it. I think they are similar to the way you would attach a TDK carriage.

[mhackney]

vacpress - I did get the bearings with the bolt holes. I did a quick price check of the meatier W version (you can get prices from the igus website) but the N seemed more than enough for my job. I didn't think it made sense to over engineer the linear bearings when I am using mdf for the construction.

I purchased:

2 800mm rails (24") for my X
2 600 mm rails (18") for my Y
2 400 mm rails (12") for my Z
and 12 carraiges.

the total was about $216 plus $5 (all US) for shipping. Took 1 day to get to me (I'm oustide Boston and they are in Rhode Island). Their price for N is basically $37.13 per meter of rail and $4.24 for each slider.

[yukonho]

Thanks for that.
I wonder if one of the 80mm sets would be enough for a Y axis if mounted to a solid gantry. I will call Monday.
co

[mhackney]

I thought about that too. It was just a judgement call. In retrospect it might be a lot easier to use the wider "W" fo rthe Z. I think the specs on it are plenty for the type of machines we are building.

[yukonho]

I already have my Z linear bearings, they are not metric so the bolt holes wont line up but I can figure something out. The W bearings are more than twice the price. Will be good to hear your impressions and see the pictures.
co

[mhackney]

Here is a closeup of the carraiges top and bottom. The arraige on the left is right side up. The one on the right shows the recess where the bolt head fits.

[mhackney]

Here is a photo with the left rail assembly installed. I ran out of nuts so I can't finish the installation until Monday!

You can see the new color here.

The sequence of assembly is:

1) install 1 rail
2) fit all 4 of the carraiges on the gantry bottom
3) position the other rail.
4) drill one mounting end hole (similar to the one you can see in the photo)
5) install bolt
6) move carraige to other end
7) drill and install bolt
8) drill and install middle bolt

Each rail assembly is attached to the base by 3 bolts. The rail assemblies can be shimmed up and down and the mounting bolts allow parallel adjustment.

[mhackney]

oops, here is the photo!

[yukonho]

Looks good.
Are they just a super accurate fit into the rails or is there something I am not seeing? how smoothly do they slide? can you detect any play in them?
Nice pait job too, I hope your lungs are OK
co

[mhackney]

yukonho - they are a very close fit in to the rails. The bearings themselves are a polymer held by an aluminum frame - you can see it in the closeup post above. They slide very smoothly with very little pressure. I can not detect any play in any dimension.

I really like this new color. It is an acrylic Krylon spray and it is very low oder. My lungs are in much better shape and the family have not evicted me (yet).

I have the gantry base painted and drying and I mounted 2 parallel stiffeners under the table (I'll show those tomorrow). I don't trust mdf to not sag even over 2' so these 2" x 3/4" stiffeners act like a "t" beam and should prevent that. I am planning a similar stiffener for the gantry base.

[yukonho]

Thats good news.
I am going to go on a limb and try the 80mm one solo for the y axis.
My first router confirms your thoughts on the sagging table. Even if it is a short unsupported run, it will sag and flex under pressure. I was cutting something once and put my hand on the table and that was enough for it to flex far enough that I didn't get a through cut. I have gone with a much more rigid box structure and moving table design for number 2.
co

[Pistachio]

Hi mhackney,

I see you got the Igus slides up and going. I have been using my router with the Igus stuff and so far no problems. I really want to see how your table comes out and if you have the same issues I had when I went to tighten the shuttles like we talked about earlier. I think I have some table sag as I have a low spot in the middle of the table. I should strengthen it up like you mention above. Good work.

MM

[mhackney]

Pistachio - thanks for the update. I hope to have some more progress photos tomorrow. I ended up cleaning my shop last night and tonight to make more room! I can get back to construction now that all the painted parts are dry.

[mhackney]

this was my original idea for fitting the carriages to the base of the gantry. Each end of the gantry has 2 carriages.