Chapter 4 - Table and Rails
Parts for the KRMx01 Table and Rails
It has been a while since I had any time to work on the KRMx01 CNC Machine. I have been working a lot, but hey, you have to pay for this stuff some how, right.
In these two pictures you see most of the parts needed for this chapter. Not shown here are the aluminum angles needed for the rails and the MDF top. I need to pick up another sheet of MDF for the top and the aluminum is not in the pictures but I do have it.
Positioning the Struts and Right Side Beam
The KRMx01 table has been placed in position of where I plan on letting it reside and has been all leveled up and ready to start construction on it. Here you see the struts have been laid in place with the rear strut clamped in place. The struts are hanging two inches over on the right hand side. The right beam has been slid into position with the outer end bolts just snugged up to hold it and the rest are finger tight.
Setting the Left Beam in Place
Adjusting the Beams into Position
At this point a piece of the MDF that will be used for the top is slid between the left and right beam. The beams are set as perpendicular and parallel as possible. When we were happy with the alignment, the outer end bolts on the left beam were snugged up and the distance between the beams were remeasured to make sure they were still parallel. Next all the outside bolts on both of the beams were tightened. Again the alignment and distance were checked to make sure that they remained square and parallel.
Beams Bolted Down to Struts
Finally, both beams have been fully bolted into position on the struts. They have been checked and rechecked for squareness and parallelism. The struts are now ready to be fastened down to the table. The machine is starting to look pretty good to me. All pimped out it red, black and aluminum.
Bolting the Struts to the Table
Getting the top and Rails cut to size
Here I am preparing the material for the top and rails. The pieces between the Y-Axis are 40" x 48" and the rails need to be cut to 54". The weather forecast is for a couple of cold days, so I will have to wait to paint the top pieces, but in the mean time I will cut the aluminum angle pictured to the left to size, mark it and drill for the bolts. Also, I need to prepare some of my 1" carriage bolts so they will slide in the T slots on the beams.
Y-Rails ready to bolt to Machine
Installing the Y-Rails
Here the bolts are slid into position for attaching the rails. This part of the project is much easier if you have a helper. Although the bolts slide free in the track, when you get fourteen of them and the metal in place you basically have no adjustment. So make sure to place the metal at the one inch mark and slide the bolts where they need to be. Another thing, when working with the bottom bolts, if you have large hands and things clamped onto place, they are fun to get started. :-)
Y-Axis Rails Completed
Painting the Table Top
It has finally warmed up enough to paint the table top. I ran into a self induced problem. I never gave any thought to the weather and the paint was stored out in the building with the machine. It went through a few freeze cycles. When I opened it to mix it up, it was at best like stirring up rice or wheat berries. Lessoned learned. To paint the top, I used some Rustolium primer and paint. You can see from the pictures that the edges really need to be sealed in one manner or another. Probably some Bondo or epoxy would be the ticket, but I didn't have any. I may seal it or just use it as is. I don't know. It will be in my building and out of the elements and sooner or later I will install some heat and air. So I just may leave it like it is.
Attaching the Table Top
Here you can see that I have got the table top bolted down. If I were to make one suggestion it would be to use a 1/8 inch bit to pilot the holes, then follow with the 3/4 inch Forstner bit then finally run the 1/4 inch bit through. I used the authors suggestion of a piece of scrap to guide the Forstner bit. This works but is difficult to hold down. All in all I am pretty pleased with the project. The machine is gaining quite a bit of mass at this point. I think I will be well pleased with it.
Next I have to take a detour and make the rail conditioning board. I will document it in Chapter 1, and come back here for the finishing touches of this chapter when I condition the rails.
Conditioning the rails
The rail conditioner is detailed in Chapter 1 - Getting started. There you will find a video of the conditioning board being cut on my JGRO router and some notes on it's usage. This design does work pretty good. The first image shows the conditioner clamped to the right hand Y Axis rail. The image on the right shows the rail complete. If you look closely, you can see that the top of the rail is tapered to match the bearing. The gap on the rail is about 1/32" across.
This concludes Chapter 4. Check out Chapter 5 where the Y Axis carriages are made. See you there!!!