Chapter 1 - Getting started.
I am not sure how much attention this chapter will get from me. I recommend you read this chapter of the book if you have never cut or worked metal. But the bigger story here is the Rail Conditioning Board. I am not ready to build this part but will go into it here along with any other preliminary stuff.
Building the KRMx01 Rail Conditioner
Detailed dimensions of the KRMx01's Rail Conditioner can be found on page 14 of the book. My wife thinks she would like to learn a little about CNC stuff, hoping to turn it into a small part-time family adventure. So with minimal help she drew the part up in LibreCAD so tool paths could be created for it. Maybe this is cheating a little, but I decided I would use my JGRO router to cut this part. Mostly for the slots because I knew it could do a better job of it than I could by hand.
Below is a video of the Rail Conditioner being cut on the JGRO router. I have to cut slow on my little wooden machine because of rigidity issues. I cut this piece at 15 inches per minute. I can cut up to about 25 inches per minute but thought I would slow this down to help eliminate any errors due to flexing. Truthfully, this would not have mattered as this isn't a precision part. The video below is played at 6X speed to prevent one from pulling their hair out. As for me, I don't have much left to pull out! HAHA
With the main portion of the Rail Conditioner cut out, there are still two holes to drill on the end for the adjustable bearings. This gave me the opportunity to use a cool little doweling jig that my wife bought for me for Christmas. You can click on the images to the left for a larger viewable version of the image. The first image is of the Conditioning board as it came off the JGRO machine with just a little bit of sanding to knock off the sharp edges. The second image shows the two holes drilled into the end of the piece to accept the bolts that will adjust the bearings. The doweling jig my wife bought me was supposed to be self centering, but as you can see from this photo, it doesn't do that great of a job at self centering. Oh well, it will server the purpose.
Next the hardware has been gathered up to assemble the Rail Conditioner. On the image in the left you will see all the hardware required to assemble the Rail Conditioner. Here if you look closely you will see that I am using a couple of 1/4" x 20 screws for the adjusting bolts with a couple of nuts locked at the head. This is so I can get a wrench on them to turn them. The book calls for bolts with full threads and the ones I had were not, so I improvised. I dropped into the local Fastenal store to get some but they had to order them. I told them to go ahead and get me some, but will try this while I am waiting. In the second image you see four 3/8" x 16 bolts with a shoulder. I was going to use these for the bearings but the shoulder on the bolt flared before getting to the head and when I slid a bearing on them it would slide up to about an 1/8" or 3/16" from the head. Rather than driving the bearing onto the bolt I decided to use some that were all thread.
Next we have the assembled Rail Conditioner. There are a couple of things that I think are worth pointing out about assembling and using this thing thus far. The washers that I have look like they are stamped. And as a result of that, one side is nice and smooth and the other has a little sharp edge that goes around it. While playing with the thing I noticed this sharp edge would dig into the MDF and shave it a bit. Flipping the washer that goes next to the wood so that the smooth side lays against it seemed to take care of the problem. Finally, tightening the bolt - bearing assembly until the lock washer is fully closed and just a tad more seems to work fine. Tightening it more just adds undue stress on the adjusting bolt you are using to adjust the bearings.