New Machine Build- 49" x 97" MechMate Build in Houston Texas, USA (detailed log)

[dmoore]

Let me first introduce myself - I am David and I live in Houston Texas (actually near the Woodlands), in the US. I am a fulltime software engineer for a large chemical company. In my spare time, I build mostly art projects - art cars and sculptures in metal. In the fall of 2007, I finished my new 1,300 sq/ft workshop that now allowed me to have enough space to pursue CNC. I spent tons of time on cnczone.com looking at all the options for a plasma/router combo table. I came along the plans for the MechMate but I knew that I would have a long road to go down with just the CAD/CAM/Mach 3 and general terminology of CNC. So, I saved off the MechMate plans and decided that I would build a smaller MDF based CNC machine and see how well that worked and if I could master the necessary skills. Well, I did build the smaller CNC machine and faired pretty well (see attached). I was amazed at what I could do with such a basic machine.

I tried to think ahead and purchase MechMate items that could be transferred over - the PMDX, the Gecko's, Mach3, etc (see attached). Well the time has come to build the MechMate. I started like I think most people do - printing out all the plans and pouring over them until I felt I had a pretty good grasp on how everything went together (I highly recommend printing them on 11"x17" paper in landscape). Next was to assemble a bill of materials. There were a few attempts at a BOM but they were a bit short on detail so I decided to create a highly detailed BOM (see attached) with every washer, bolt, nut, motor, wire, etc - everything. That took about 30 hours of researching, reviewing it against the plans and researching vendors. I currently have ordered about 4,000$ and expect the total (excluding software, Gecko's, computer, etc) for the table (including motors, sensors) to come in at about 4,500$ to 5,000$. I will be releasing the complete BOM once I complete my machine and verify that everything listed is complete and exact.

Continued in next post...

[dmoore]

I started out by ordering as many of the parts as I could. I personally expect that the research and ordering of parts is as much as 25% of the total build time - we'll see. I am trying to stay as close to the plans as possible but I've decided to deviate from the plans in the following areas:

Legs - Instead of channel, I am using 2"x2" box tube
Cross Bearers - I will be bolting instead of welding due to weight issues (and I have to move in 5 years)
Rails - I will be using ground angle, though it's dimensions will differ from the plans (not Gerald approved)
Gantry Tube - I will likely be welding the Y rails to the gantry tube instead of bolting as Gerald did in his orginal MechMate

I will be building with the following options:
Optional X-Axis Chains
Optional Proximity Sensors (18mm instead of 12mm)
Geared motors with 30 tooth pinion
Milled/Ground Angle for rails

My first purchase was steel. This seems to be were the most variability occurs - steel is a local purchase and varies in price and avaiaiblity on a vendor by vendor basis. There are a number of steel vendors in Houston - most of them cater to companies but one is more of a "wal-mart" of steel and sells in single stick quanities without any minimum and are even open on Saturday. Of course they are a bit more expensive but they usually have what you want and it's easy to get. SSS Steel is my steel vendor (www.sss-steel.com). They also have a great reference of common US steel sizes here: http://www.sss-steel.com/front/frReference.asp . Here are some photos of my steel order and my special trailer that I use to bring home full 20' sticks of steel:

[dmoore]

Here are photos of my other parts. I'm still short the rack, motors and paint but everything else is here. I ordered my laser cut "full options" kit (see below) from jbmclain (Joe) in Alabama for $420 (including shipping), including non-v groove bearings with the geared motor option. Highly recommend Joe if he is still doing group buys on parts.

I ordered nearly all my bolts, nuts and washers from www.boltdepot.com. I ordered everything except for the carriage bolts and nuts/bolts for the skate in stainless steel insted of zinc finish. It was only about 90$ for all the nuts and bolts (see below). I highly recommend them - I will have each of the part numbers from them (in stainless) in the BOM. They ship quick, the price is good, you can purchase quanities as small as 1 and they package EACH type of bolt/nut/washer in a seperate bag with the description and part number - which the BOM has a cross reference back to the specific page the parts are used on.

I ordered most of the misc parts like the cable management, springs, gears, etc from McMaster-Carr. They ship quick, the quality is always the best and the website is super easy to use - the downside is you pay for what you get. Most of the stuff is brand name - the gears are Boston Gear, the cable chain is Igus and so on. I understand they are not so great when it comes to shipments outside the US, but inside the US - el premo. In the photo (see below) you will notice that I went with adjustable, non-skid feet with insert for the 2x2" legs I've decided to go with.

The remainder of the items came from Automation Overstock (www.automation-overstock.com), Factorymation (www.factorymation.com), ACE hardware outlet (www.acehardwareoutlet.com), WT Tool (www.wttool.com), Superior Bearing (ww.superiorbearing.com) and K2CNC (www.k2cnc.com) - all shown below.

[dmoore]

I started with cutting the cross bearers for the support board. I used a 14" chop saw and cut them at the suggested 60 degree angle. I cut one and then used it as a pattern for the remainder of the cuts and it came out pretty good. I did have to re-set the circuit breaker about 50 times but they did cut - total time was about 3 hours. Another 30 minutes or so to clean up the welds. See photos below.

[Jason Marsha]

Thanks for posting here in the zone. Now that's a lot of heavy steel, you should be able to skip the gym while building this baby.
Your shop looks nice and roomy. Keep those pics coming.

Jason

[biotech1]

how much was your lazer work and bending??

[Jason Marsha]

Originally Posted by biotech1 how much was your lazer work and bending??

Post #3

[dmoore]

Well I've given up on welding the Y rails to the gantry tube and now I'm going to bite the bullet and buy the materials needed to properly cut the rails down to the required 1.1" as my steel supplier doesn't sell the 2"x1 1/4"x1/4" angle. The Aluminum and steel rail combo isn't really any cheaper either, even with tools.

As to the progress... I've drilled all the support bearers. Since I am building a bolt together table, I've drilled 1/2" holes for bolts through the support bearers for attachment to the flange of the main beams. I also stamped identification numbers so if in the future I have to reassemble it, I can get it in the right order. Total time to measure, stamp, punch, drill and then redrill was about 2.5 hours. Here's a tip (I suspect that most people may know..) when measuring out the holes for the outer and inner (on center line of the channel) - find the center and set that on your caliper. Drag the caliper along the outside edge of the channel, scoring a line.

[dmoore]

Today I turned the hold-down idler stub shaft. I'm happy to say that my first ever attempt at turning turned out ok. I used a cheap Harbor Freight 7x10 lathe: http://www.harborfreight.com/cpi/cta...emnumber=93212. I turned mine a little to loose so that the press fit was more like a push fit so I tapped a hole and put on a fender washer to make sure it stayed in place. Photos below.

[dmoore]

A few suggestions on cutting the main beam:

• Don't use a plasma cutter - the arc wanders too much
• Use an 1/8" metal cutting disk (or maybe 10)
• Use a right-angle grinder 10amps or better, the 7amp units don't cut it
• Make sure to have corse grinding wheels
• Watch your toes and fingers if you are handling the beams by hand
• Be sure to wear a dust mask

[dmoore]

I scrounged around and found some 5 1/2" x 1/4" plate and then trimmed it down to the 3.5" width to close in my beams. Cutting them wasn't a big deal but the welding, and dressing took about an hour to get them really clean. I used a corse grinding wheel for the first run and then a flap disk to smooth it all out. I'll finish the small gaps on the inside later with bondo to obtain a completely smooth finish. Then, when I was done, I used my belt sander to clean off some of the mill scale and rust.

[dmoore]

I'm bolting on my support bearers to the main beam instead of welding them on. I'm using 1/2" bolts on mine. Shown in the photos is layout of the support bearers, making sure to off set to the proper side. I then clamped on the end cross bearers and measured everything and then laid in the other cross bearers. I then used a transfer punch to mark the main beams from the existing 1/2" holes on the bearers. I then drilled a pilot hole and then the 1/2" holes. Be sure to use plenty of cutting fluid and a corded drill. I then bolted the centers in and then drilled and bolted in the remaining ends.

I did make one mistake - I measured off the edges of the main beams to line up the edges of the support bearers, where I should have added 1/4" to each side. Nothing major.

All said and done, it turned out completely square and parrallel.