Well, money isn't everything but we can do much without it... OK enough of the ranting, lets get back to the fun :D

I hand painted & recon it had cured enough (over 1 month) before I get to tape up the rack. Hope my paint job is good enough to hold.

Lordy thats one thing that scares me,... painting. I have a ton of patience but when it comes to painting,... I do not. dont know why. I would seriously have to try hard this time around because this just isnt an old rusted bicycle, lol. A lot of the machines I have seen on this site have amazing paint jobs. I didnt read to deep into their threads to find out if they had the parts painted or they did the parts themselves or what. Im think I will try myself. Get a nice spray gun and give it a go. I have to research all that though. Last thing I want is chipping.

I hand painted using roller brush. prefer it this way. Even though I can borrow a set of spraying equipment as long as I bother to ask. & there is a paint shop less then 30m away.

My strategy is to choose all the methods that I know & well enough with the tools I have. If I need/want to learn a new skill, such as spray painting, I'll start another project for it.

Building the MM really doesn't need special skill, the only skill required I recon is to stay focus on build & stick to the plan as much as possible. Which is really a huge challange:(

LOL. Good advice. Well I do agree with you on using what you know now to do what you need done now. But for me,... same as the rails. if theres somethnig I want to do i have to do it. if I dont it eats at me. I'll redo it. I have scrapped completed projects that were near perfect except for a tiny flaw. a dumb flaw. the kind of flaw whre your yelling and screaming "STUPID STUPID STUPID!" Its crazy. Totally ridiculous. I am extremely anal. A perfectionist.

I cant say that you dont need special skills to make a MM. Because you do. The only real skills I think someone needs to do ANYTHING is patience and perfectionism. Straight up.

Following plans 100% is a real problem for me too. LOL.

Wait a second... your house came with a girlfriend? ;)

And a huge garage! What more can a guy ask for! LOL.

Almost done with the details. Looks pretty much like the ground rail. A combo of the two options available. Theres a TON of bolts per rail. I believe there are 21 - 5/16" bolts hold the hold assembly to the main beams. Theres,... 21 - 8-32 bolts hold the rack to the flat bar. Theres 29 - 1/4" bolts holding the v-track to the angle iron.

I decided to mount the v-track to the angle iron flush, v-track lip resting ontop of angle iron vertical leg. At that point I will treat the entire assembly as if it was a MM ground rail. Meaning then I will shim up the whole thing as one piece until the v-tracks are true to one another.

It will work. I just have to make damn sure that I am very precise with everything. Especially cutting/ grinding the angle down to size. Im going to purchase a horizontal bandsaw to make all my rough cuts. I think I will build some kind of jig like table to fine grind the angle to it target size making sure everything is precise. Might buy and extra to practice on,... or better yet if I mess up i'll just buy another.

The v-track is bolted with 29 - 1/4-20's that screw right into the angle iron. No bolts. I read that 1/4 - 20's can be torqued to about 125 in/lb or about 10.4 ft/lb. Thats more than 290 ft/lb total hold the track to the angle. A lot of the weight will be rest on teh track lip. So im not worried about the track moving. I believe the bolt interval is 4.3125". v-track is T3.

This is my plan.

Hi
In post #10 it suggests shimming at S1. Is this necessary in the set up phase? Or is it easier to keep the steel and al tight and do any shimming between the Al and the steel channels?
I am not sure if I should locktite the rails to the Al and keep my 6mm holes or drill to the 8mm clearance holes suggested on the plans to allow for shimming.

Thanks
David

I am in the process of building my own CNC machine (not a MM) and I'm trying to incorporate lessons learned by others into my final design. After reading all the replies to this post, I find one flaw to the use of capped rails. Capped rails are nice and straight, but the surface you bolt them to must also be nice and straight. I suppose you could shim the rails at each bolt hole (tedious), but if you are going to go to the trouble of using capped rails, which are expensive, a better way is to use steel angle rail and grind the V profile with the skate fixture. I could see rails for the Z-axis, being much shorter than the X or Y axis, could be made perfectly straight on a milling setup, but 8 foot rails? I can't see any advantage to capped rails.

I would like to have gone the MM route, but I started my current machine over a year ago and I have much time invested in it's design. My agenda for building a CNC machine is different from most other constructors. Aside from cost, I am trying to educate myself about how to build CNC machines. Getting one built in the shortest amount of time regardless of cost is not my agenda. To me this is a learning experience. I want to start from the bottom and work my way up.

So far, I have seen many different designs and ideas, some good, some not so good. I'm trying to approach this in the same manner as learning another language. I find the MM design is a very good one. The main good point is the location of the router, between the gantry rails. Other conventional designs have the router and carriage canterlevered from the gantry which places much stress on the gantry and the Y and Z bearings. My design, although of plywood construction, will incorporate the MM router location. The Z-axis bearings will still have an off center load on them, but I am working on that.

My being on this forum, is not so much to ask for advise, but is to present my ideas for your evaluation. My approach to building a CNC machine is from an engineering point of view and although the MM is well engineered, I have committed myself to keeping the cost down as much as possible without ignoring good engineering practice. I know cost is a concern for many as it is for me and even the relatively low cost of the MM is still out of my range. Those who have committed to MM and are happy with the results, shouldn't be concerned by my comments.

Ron,
Not to be difficult, but this site is dedicated to MM fabrication and use.
The Use of Cap rails, or ground rails in the MM design - for the MM design - are proven and accurate when applied to this design.
The use of the MM method in other machines is not a point of discussion due the all the variables involved. The forum is not "closed to other ideologies", but only in the need to focus on those committed to the MM design and not others.

You mention that some ideas are "good and not so good". I personally feel that is a relative opinion.

The MM design is final. It has 100+ units in production currently without many issues.

I wish you luck with your endeavor - but evaluation discussions might be best suited at the CNC Zone or others.

Best,
Sean

I agree with Sean.

I think you will be happier at the CNC Zone where others are building machines of all kinds of designs. The MM forum is primarily focused on a MM machine with slight variations that the build wants.

Good luck with your build.

I agree with Sean and Nils also. BUT I do also think you will be more satisfied in the long run to get the kits I sell and build a MechMate.

These kits are for sure not plug and play. They give you a running start on getting a machine going without duplication errors or "I ordered the wrong parts !! " errors. Sell the stuff you have now over on the zone if it won't work on a MM.

Also you will find on this forum many finished platforms and support focused on one machine. We do that here so you have a built in support system for the machines once they are built. That is probaly the best item/thing that comes with building a MechMate .... real people with real experience telling you (more often than not) what NOT to do becuase THEY did it and it costs them a lot and it did not work in the end and they came back to the basic design.

Have fun on your build. But if your not doing a MM you will get more feedback on the Zone.

..Continuation of thought.
I re-read the rail post a few times last night with regard to the requirement of the angle iron rail being cut to the proper height for the capped rail system to work effectively.

I then saw the post above that with pictures of Charles idea for mounting the cap rail. Both assumptions of your post indicate that your putting the rail itself on top of the bisected rail section.

This is not the method developed, but others have done exactly what is shown with success.

Gerald worked out a method that the cap rail base (which is the factory machined surface furtherest away from the point) to sit on an extruded architectural aluminum angle thus taking the leg length cut out of play. If you using steel structural angle, then you will have to have an accurate leg height (which the skate cut method does).

There is not point to this post other than me clarifying the assumptions in the prior post.