It is CUTTING! Bolted Mechmate with linear bearings - Kansas, MO
 

OK, I've been on this forum for almost a year, completed the kitchen sink project a while ago, but the build of the structure of the machine has taken longer than planned.

My machine is a little different than most here. As the title suggests, it is a bolted together construction, but I did weld the major subassemblies. Basically, i wanted to be able to assemble/disassemble by myself or with the help of one person. I've actually done that by myself a few times now. I'm also using linear bearings, as before I found this site, I had purchased a set of those. This limits my table to about 6' of X travel (Y is about 4' and Z will be about 12"). In modifying Gerald's plans to allow the use of linear bearings, I tried to make it so that I could go back to V-bearings if I had the need for the full 8 foot of X travel.

Sorry about the red color, but the price was right. A friend who owns an autobody shop had a gallon of 2 part enamel he didn't need, and offered it for free.

Here's some pictures

Looks great, where did you get your parts cut? With me living in Kansas too it would be useful to find a local place to get parts cut for the build.

I used the Joe Mclain parts (Sweet Home Alabama). Didn't even attempt to source it around here as his price seemed reasonable.

Kevin,

She's beautiful. Congrats.

Congrats on a really nice table. WIth that nice Red color, maybe some pinstripe or flames would be in order?

Very nicely done.

Kevin,

Great looking machine. I like the red paint....makes it feel fast, like a Ferrari :D

Wayne

Kevin,

Nice bright color.

Why did you decided to go with linear rails and bearings?

Welcome Kevin.

I am curious to see what your motor tuning/performance is going to look like. (Suspect that the friction of those bearings will reduce the speeds a bit - youtubes one & two)

Thanks for the positive comments. As for why the linear bearings, as I said, I had somewhat planned a build in my mind using them before finding this site. Mainly because of their perceived precision. It will be interesting to see what kind of precision and repeatability I can optain when complete.

Gerald, you bring up a good point. While it is not difficult to move my gantry or Y-car, there is definitely more friction than with the V-bearings. I would think the mass, and therefore the impact on acceleration/deceleration would be a larger impact on overall speed, but no doubt the friction will come into play.

Oh, from what I was told, it is Porsche red, so I guess it should at least LOOK fast.

Kevin, I have some experience of using a linear bearing in the z-slide of the first MechMate. It has worked perfectly since day 1 and hasn't needed a moment's attention since. So, I can only speak well of linear bearings so far. That is why I will be looking at your results with keen interest.

Can't see from your photos, but remember to put the plugs into the rails over the screw heads. Most cases where I have seen linear bearings being used, those plugs were not fitted. Without the plug, the seal cannot wipe the top of the bearing rail clean.

Kevin,

Nice machine!

Did you factor in the cost of all the traffic tickets you get with a red machine?

Looks REALLY great!

Gerald, none of my rails came with plugs. Are they just a press fit piece of plastic?

I looked at your original design with the linear bearing z-axis. I had in mind something similar. From the pictures, I do not see any spring to maintain contact with the rack. Did you use a spring, or more of a fixed mount? Thanks.

Yes, they are just press-fitted plastic. You press them in with a plate over the top to get the plug perfectly flush with the rail. Good rail suppliers will supply the plugs with the rail - didn't any fall out of the box when you unpacked yours? :)

The spring is very visible in this post.

I see the spring now. Thanks Gerald. I bought these some time ago off of Ebay. I'm fairly sure there were no plugs, and it's too late to complain now. I wonder if I could find a plastic rod of the correct diameter, and cut it down into little plugs?

Suppose you could also pour some filler into those holes and then slice off the excess once it has set?

Different Z-slide approach
 

I think what I'll do is put something "soft" in the bottom on the hole, such as modelling clay, then top off the hole with epoxy or filler. That way if I need to get the rail back off, I can.

Some more progress to show. Here is my Z slide assembly. It's entirely aluminum to try to minimize moving mass. As you can see, I will have up to 30" of travel by unbolting the cross members. The linear rails bolted to the aluminum plate add quite a bit of stiffness, but I am still concerned with flexing while traversing under load in the X-direction. I have about an inch of clearance on the back side of the plate to add a T or U section for additional stiffness. It still needs some refining, but you get the idea.

Different Z-slide approach
 

Opps, sorry about the pictures being sideways. Is there a way to edit the pictures once posted? Fixed since

Try waxing the holes with a q-tip and filling them with Sika-Flex. It is usually used to fill expansion joints in concrete. It remains rubbery forever and it is very easy to use. Just squeeze from a caulking tube. Awesome stuff. Available at concrete supply houses.

BTW: Your machine looks great!!!!!!!!!!! The only thing that would improve it is a little blue paint.

Sorry, I couldn't resist. :D

Very interesting work Kevin!. Here is a good way of stiffening the long slide - you have loads of space for it.

hi,

my question might be a little bit naive, why do you need such long z-axis?

I´ve had a couple guys express interest in having me cut foam molds for race car and custom car body panels. Plus, the incremental cost was insignificant. As I´m set up now, my z travel is only about 11 inches. If and when one of these jobs come through, I will make modifications for 24 inches.

This is my first post....
Congrantulations... my friend this is beaudiful

Thanks Jonny. I am on vacation in Brazil right now. Will post some more pictures when \i get back. I hope to be cutting within a week or two after returning. Don´t tell my wife that I am suffering withdrawals from working on the machine. :D

Maragogi

2.500 Km :eek:

Wow, Gerald has got a memory like a steel trap! Yes, we are in Maragogi. About 120 kilometers south of Recife. I´m curious, the guys from Brasil, what kinds of things are you going to be cutting with your machine?

Wood and aluminum ... Gerald although not like this material

Aluminum: http://br.youtube.com/watch?v=nGH6kT...e=channel_page

and future: http://br.youtube.com/watch?v=w28SzD...eature=channel
:cool:

and before: http://br.youtube.com/watch?v=rbcGQI...eature=channel

I love aluminum!

. . . . . . . when it is used correctly (yes, airplanes are perfect example), but I hate it when alu is used just because it looks clean/modern and when steel will do a much better job. You can also make steel look clean & modern.