KRMx01 Build Log
Chapter 5 - Y-Carriage Construction
It is time to start the Carriages. I am glad because I would like to see some moving parts and this at least gets me started.
Material for KRMx01 Y Carriages
Marking and Punching the Angle Iron
After cutting the angle iron to the size specified in the book, it was time to mark and center punch it. I have always had a hard time marking angle iron so that I could see the mark clearly. For fine measurement I have had a bit of difficulty getting the mark where it should be with the tools I had on hand. My solution to this problem was to paint a light coat of flat white paint on the angle iron and use the height gauge pictured in the second image to scribe my marks. This worked incredibly well for me. The gauge is was $60 dollars I think and will measure up to 6" in .001" increments. It is Chinese made, so I don't know the quality of it, but does a fine job for what I bought it for. Once I zeroed the gauge, I would simply set it to the height I needed and pull the angle iron across the carbide tip scribing the line. Just thought I would pass that along.
With the marking and punching out of the way, the KRMx01 Y-Carriage tops and bottoms were drilled, tapped and the slots cut for the v bearings. The second picture shows the KRMx01 Y-Carriage supports. I have deviated from the book here. The reason for this was the new anti backlash nuts from cncrouterparts.com is different from the original. The original nut was an all plastic unit. The new nut is contained in an aluminum housing. These nuts ship with 5/16-18 socket head bolts. In order to have some room for adjustment, I drilled the two center holes at 3/8" rather than the specified 5/16"
Some notes on the Anti-backlash nuts
The original plans for the KRMx01 CNC machine called for cncrouterparts.com part #CRP109-00 and has been replaced by part #CRP161-00-02. The difference between these two products are minimal and I have included links below so that you can view the associated PDF documents on them. The only major difference between the two nuts that need to be taken into account are the total height of the assembly. The original #CRP109-00 assembly is 0.825" and the new #CRP161-00-02 assembly is 0.980". The difference in height between the two is 0.155". Because of the close proximity of the nut to the Y-Beams, a spacer of about 1/16" will need to be placed between the Y-Carriage supports and the Y-Carriage Top and Bottom. In a post on the CNCZone Kronos forums, Michael Simpson, the author of the book, had this to say:
It looks like CNC Router Parts has pulled the original nut.
In any case the new nut is not a direct replacement. The problem is that it needs more clearance. You need about 1/16" more clearance for the nut to keep from hitting the Y-beam. I did this by inserting a small piece of 1/16" thick aluminum between the supports and the main frame.
Refer to Step 7 in Chapter 5. I cut a small piece of aluminum 1" x 2" x 1/16" from 1" x 1/16" aluminum bar. You will need to mark the holes to match those in the main frame and support. You will need four of these for each carriage When installing the supports to the main frame, the aluminum spacers go between the two. This will pull the supports about 1/16" further away from the beam when the carriage is attached to the rails. As for the screws I still used the 1/4" bolts. You can use the 5/16" bolts but will have to drill larger holes. If in doubt use 1/4" bolts.
The motor/bearing mounts have enough play that you should be able to easily compensate for the 1/16" difference before tightening.
It has been awhile since I did this mod so keep us informed.
The key is to have a little play so you can line up the nuts.
Painting the KRMx01 Y-Carriage
The angle pieces are painted and ready to be assembled, well sort of. They need to cure for a bit for the paint to harden, the bearing adjuster holes need the tap run back through them to clean the paint from the threads and I need to cut the above mentioned spacers to go between the carriage support and the top and bottom pieces. Other than that, well we are golden! :-)
Making the Spacers
I thought I would assemble the carriage without spacers to try to get an idea of how much I needed to go. Just trying to eyeball it, I thought the 1/16" spacers would do the trick. I decided I would use 1/4" washers for the spacers, they were just a little over 1/16" and I thought, what the heck. That would be a simple fix and everyone has access to washers. I took the callipers and measured a bunch of them until I found 8 that I felt were close enough to the same size. I assembled the carriage again for another test fit. Hmm ... it was still hitting the Y-Beam, but just barely. So, I thought I would do it different. I cut 8 pieces of 1/8" x 1" strap 2" long. The image on the left shows the pieces I cut. (By The Way, my wife is a little OCD, so I thought she would love this picture!) Next, I coated them with some flat white Krylon spray paint so I could easily marked them. You can see this on the image to the right.
Next I marked and punched the centers. The lines are marked like the Y-Carriage supports, a line is scribed 3/8" from the edge, and then cross lines are made at 3/4" and 1-1/2" from one end. The image to the left shows them scribed and punched. Next, I piloted all the holes with an 1/8" drill bit and then drilled them 5/16" just like the Y-Carriage support pieces.
Finally the spacers have been painted and when dried well I can continue on with the assembly of the Y-Carriages. One thing that should be noted is that by using these spacers the center points of the bearing and motor blocks will be off. Since I have not cut these items yet, I will redraw them moving the motor/screw centerline by 1/8" for the Y axis. Similar steps will have to be done for the X-Carriage and Z-Carriage assemblies.
Assembling the Y-Carriages
Now that the spacers for the Y-Carriage supports are finished, I can start assembling them. The part list is the same except for the anti-backlash nuts. The new nuts come with socket head 5/16-18 bolts. I am using these rather than the suggested 1/4-20 bolts from the plan. I am using 1/4" flat washers, 5/16" lock washer and 5/16" nuts with these. Remember, I modified the supports by drilling 3/8" holes for the two center holes to allow some room for adjustment with the larger 5/16" bolts.
The assembly of the Y-Carriage is exactly the same as in the book with the exception of placing the spacers under the Y-Carriage support pieces. Since the spacers were cut using the same layout as the support, you will need to pay attention to how the spacers fit into place so they do not extend past the support piece. The images to the left show everything in context.
The KRMx01 Y-Carriage assembly is now completely assembled. Next they will need to be fitted to the Y-Axis beams and adjusted so they are both parallel and at the same height to each other and the beam. We are getting close. I feel the X-Beam coming on!!! :-)
Fitting and adjusting the Y-Carriages
Fitting the carriages to the Y-Beam rails was a pretty straight forward process. Loosen the lower adjusting bolt and back it out enough for the bearings to slide on the rails. The tedious part was adjusting them to the same height, well at least to about .001". Both carriages are the same height from the top of the Y-Beam and both the front and back of the carriages are the same height. This little height gauge came to the rescue again. I am using the plate that will become part of the Z-Axis to hold the router clamp as a base for the tool.
The Finished KRMx01 Y-Carriages
See you in the next chapter. :-)
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!!!
Chapter 3 - Y-beam Assembly
Parts for the KRMx01 Y-Axis
These three images just show all the parts needed to complete the KRMx01 Y-beams. I purchased my 80/20 parts pre-cut from the site that Michael suggested. But along with it you see all the hardware needed to assemble it together and the four pieces of 2" x 2" x 1/4" angle needed to create the bases of the Y-beams.
Assembling the bolts for the uprights
I though I would start with something simple and get the threaded rod pieces assembled with the T slot oval nuts and washer, lock washer and nuts. These will be needed when the assembly gets put together. It was a little frosty in the man cave when I started out, so I thought this would be a good job to do while I was drinking coffee and warming up to the work ahead so to speak. :-)
Drilling the Angle Iron base pieces
Here I have set up one of the angle iron parts to be drilled. I don't have a lot of room in my shop and had to improvise on the set up a little bit because I have a small drill press. I marked the piece and used a center punch to make a dimple to help guide the drill. I used cutting oil and took my time. I did not have any issues from not clamping the material down. One thing you do not see in these images is that I have a paint can and some 3/4" MDF pieces supporting the angle iron on the end. This stack is made up so as to hold the angle level as possible. Once the dimple was lined up with the 1/8" pilot bit, there really wasn't much to do but drill the hole. I finished two of these today. When you drill an 1/8" inch pilot holes then the 3/8" holes for each piece, by the time your done, lining them up and drilling becomes second nature. Man there are a lot of holes!
Bottom angle ground, drilled and cleaned
Here are the bottom angle iron pieces. There are holes a plenty to drill here. Twenty-eight holes per piece, each one of them center punched, drilled with an 1/8" pilot and followed through with a 3/8" bit. I should take a picture of all the swarf around my little drill press. These 2" x 2" x 1/4" angle will add a lot of weight and rigidity to the machine. Michael Simpson, the designer, was smart in selecting a heavy material for the Y-Axis of the machine.
Painting the Y-beam base angles
Here I have painted the insides of the base angles. This is three coats and could perhaps use one more. I am out of paint again, so will have to get more to finish the job. It is hard to tell if they look good in the picture or not because my drop cloth is getting pretty red from the over spray. Once they are done I will get a picture of them by themselves on the black table.
Finished painting the Y-beam Angles
Here are the Y-beam angle finally painted. I forgot to mention, the month on the images should be 11 not 10. When the battery died last time, I messed up the month setting when I put the batteries in. Anyway, I must admit, I really like the red. Melissa done a good job of selecting it. Originally I was leaning toward Blue or Green, but this is better. Next I will need to drill the uprights that get bolted between these angles.
Drilling the uprights.
When I first started to work on the uprights, I cut a drill template on my JGRO CNC machine. I actually even taped it to a piece if the 80/20 and stared to drill. I did not like the control I had on it. On my small machine, I have neither a fence (although I suppose I could build one.) nor enough room to clamp them down. I took another approach instead. I placed the upright between the angles and clamped it into position, then I drilled the holes from each side. When I finished a hole, I would put a bolt through it. When there were two bolts (the top ones) in each upright I clamped a piece of angle across the bottom to make sure that the upright was exactly at the level of the base of the angle. (flush with it.) Once I was happy the bolts were tightened down and then done the same to the next upright. When I had all four upright done like this I went ahead and drilled the middle two holes, added the bolts and made sure the work didn't slip. I proceeded like this until all four of the uprights had the 6 holes drilled and the bolts in place. The second image shows them all bolted together. It looks pretty nice.
Adding the top beam to the assembly
The image to the left shows the top beam with the threaded rod bolts in place and ready to go on the top of the uprights. This job wasn't too bad. I clamped a piece of angle to the inside to assure that the beam was flush and pre-set a square to the required five inches. After a little twiddling and resetting, the beam was in place and locked down. Here in the second picture you see the left Y-beam completed. One down and one to go.
The completed Y-beams
Here are a couple of views of the completed Y-beams for the KRMx01 CNC Machine. They are sitting on blocks because of the bolts extending underneath. These units are heavy and pretty rigid. I think they are going to work great. When compared to my original JGRO CNC machine, this one is much more rigid. I am starting to get excited about the project even though there is a LOT more to do. This concludes this chapter. I will see you in the next chapter where we finish up the table and add the rails.
Chapter 2 - Stand Assembly
The stand recommended in the book is the "Rousseau Workbench System" and is of modular design. Instead of using this system I bought 2" x 2" x 1/8" steel angle iron to make a stand. The important thing to take from the stand is the height of the legs and the length and width of the top. The legs were cut to 32" in length. The top of the table and what will be the bottom shelf are 44" long cut on a 45 degree angle.
I am fortunate to have a friend that would weld the project up for me. I have a small wire fed welder, but like I have talked about before, I don't brag about my messy spatter I make with it. John, on the other hand, is an excellent welder and was kind enough to volunteer his time to help me. Thank you Pastor John!!!
Cutting out the parts.
I cut the parts outline above with a chop saw. There are a total of 16 pieces that make up the basic table. (4) Legs each measuring 32 inches long. (8) shelf pieces that make the top and lower shelf. These are 44 inches long and the inside is mitered to 45 degrees. And lastly, (4) corner foot supports. These are 2 inch x 2 inch right triangles that will be welded to the bottom of the leg for the adjustable feet. I didn't photograph these pieces, but you will see them in another picture after they are welded on. You can click the images to the left for a larger sized image.
Welding up the Table Top and Shelf.
The fist thing we done was to weld up the table top and the table shelf. These were laid on John's steel table to assure that the top face of the frame would be flush all around. One the pieces were squared up together they were tack welded. Each piece was added using the same process. Once all four pieces were tacked together a measurement across the diagonal of the frame was made to make sure that it was in fact square. Then more tacks were made on the edge of the corners, then rechecked for squareness. Once we were happy with it it was welded on both the face and corner joints. We done this for both the table top and table shelf. The welds were ground to leave a flat clean finish. The pictures to the left show the completed parts.
Attaching the Legs and Bottom Shelf.
With the top and shelf welded up, it was time to attach the legs. Squaring the legs was a bit of a challenge to sort out. Our first try was to set the table top on its face and place the leg to it. The problem was that once to tacked one side you could not move the leg at all to make it square to both edges of the frame top. The solution was to lay the frame top on the leg, square it up on one plane, tack it and then square it up on the other plane. Once both tacks were in place, it was double checked for squareness. Once we were happy with it, it was welded up. We repeated this process for each of the legs. Once the legs were welded to the table top, the assembly was laid in the floor and the bottom shelf slid into place. Just as a note. The top of the legs are flush with the top of the table. The Top of the shelf is 25" below the bottom of the table top frame. Once the bottom shelf was in place and tacked at all four legs and we were happy with it, all the joints were welded.
Attaching the adjustable feet and bottom plates.
With the table all welded up, all that was left to do was to make a means of adjusting the table so that it can be made to stand on a level plane. John's idea for adjustable feet was to weld 1/2" bolts to a large heavy fender washer. To the fender washer would be glued some heavy rubber pads made from some shocks he had laying about. A nut is run all the way down the bolt and a washer placed on it. This bolt would go through a hole on a plate welded to the bottom of the leg and finally another nut run down the bolt. In use, the bottom nut on the leg can be turned to jack the table up or down and the top nut locking it in is final position. It was a good idea and saved me from having to buy some. The plates that are welded on the bottom of the legs are made from triangular pieces that were left over from cutting the parts out. They are roughly 2" x 2" x 1/8" right triangles with a 1/2" hole drilled through them. These are welded to the bottom of the legs on both sides of the plate. These little pieces are expected to carry the entire load of the machine, table, computer, etc. The pictures to the left will give a better view of the parts. The rubber feet will be glued on with epoxy after they are cleaned up and painted.
All the welding finished.
Here is a picture of the Krmx01 CNC stand after all the welding has been completed. Now it isn't finished yet. I still have welds to grind down, dirt and grease to strip off and painting to do. I also need to epoxy the rubber pads to the feet after they are all cleaned up and made pretty. But we had spent a little over 5 hours getting to this point, it is sleeting outside and I need to get home. I will post more as I get it done.
Painting the stand.
Well, quite a bit of time has passed since I worked on this project. Kids, work and other things tend to get in my way sometimes. Well my son Mike and I had some time to spare today so we decided it was high time to get the stand painted. We started with using an air sander and wire wheel to knock off any loose grime and rust. We also took the grinder to the welds to smooth some of them up a bit. John really is a pretty good welder so there wasn't much to take off or clean up. Afterwards, we gave the frame a good cleaning with some mineral spirits and wiped it down. These three photos show that we started with the sand upside down and painting the bottom and insides. We gave it three coats before turning it over.
These pictures show the stand right side up getting a few coats of paint. I have not sprayed any spray paint from a can in ages. It took a few runs to figure out that I needed to be a little further away from the work and not so heavy with the spray. No worries, we used all three cans that I bought. It still needs more paint. I want a nice even color and a couple more coats should give me what I am looking for. After this cures I will sand the runs and re-coat. Also, we gave the feet about four coats as well. Next we will need to glue the rubber bottoms to the feet with some epoxy or maybe just some silicone. This part of the project is just about done.
Adjusting Feet and Holes for top.
I thought I would post a couple more photos of the stand before finishing up the painting. The first image is of the adjustable feet John and I made. These are just large washers with a 1/2" bolt welded to them. The black rubber bits in front of them were made from shock absorber bushings. We ground the tops off the bushing to make them flat. I will epoxy or silicone these to the bottoms of the washer. This will allow me to make adjustments to the frame to level it out. The next photo shows where I drilled the holes for the MDF that I will use for the table top. Since I didn't use the stand in the book, I just spaced these how I seen fit. The outer holes are spaced 4 inches from the end and then the inner holes are 12 inches apart. This weekend I will finish painting the stand.
The Feet attached to the Stand
Here you see one of the feet attached to the stand. I thought this would be a good view of it before I set the stand upright proper. If you look closely, you may notice that the foot is not entirely level. Well, some of that is the angle of the shot and some of it is that it is not entirely parallel to the stand. When you weld a bolt to something, the welding tends to pull it to the side a bit. I suppose if you are careful, you could get it pretty straight. However, I am not too worried about it. The rubber foot will make plenty of contact with the floor and work just fine.
Starting the top
I have the sheet of 3/4" MDF cut into two pieces measuring 48" x 48". That is one of the nice things about MDF. A sheet actually measures 49" x 97" allowing you to get the full 48" x 48" pieces from it. Here you see the first coat of paint on the material. I intend to get enough coats of paint on this to make it a nice and uniform color. Then I will turn the sheets over and start drilling them for the bolts on the top. When the sheets are drilled and the counter sunk holes are made, I will then finish painting the top and sides. I figured this would be the simplest way to paint it. That way I didn't have to mask anything off to keep it from getting on the red stand. Note that I will not paint between the sheets. With it bolted down and the side thoroughly sealed with paint, I don't think I have a worry with moisture working it way in. I live in the south and high humidity seems to be a fact of life here.
Doing the other side of the top
Here I have started the other side of the top. The top is bolted to the stand with 16 bolts. The first image is the hardware laid out and ready. Once the bottom of the top was second coated and well cured, I flipped the top over and centered it on the table. When I was satisfied with the positioning, I drilled the 16 holes for the bolts. Four of the holes had to be countersunk for the heads of the carriage bolts because they would interfere with later construction. On these, I used a long 1/8" drill bit to pilot the hole all the way through. Next, I used a Forstner bit to cut the counter sinks then finally drilled through with the 1/4" bit. Once all the holes were drilled and the bolts test fitted, I gave the top and edges their first coat of paint. I apologize for the image quality of the painted top. Seems like I have some MDF dust on the lens. I will be sure to clean it well before I take more pictures. When the paint dries I will give it at least another coat. I want to make sure the top is well sealed especially on the edges and that is has a nice uniform color. I am nearing completion of this part of the project. I will have one more section and some discussion about what I plan to do with the rest of the stand and why I have not attached a shelf to the bottom yet. But first I need to finish the top.
The Finished Stand (Well ... sort of)
Here are a few images of the completed stand. I say sort of above because there are more things to do to the stand but these additions are a variance from the actual construction of the machine. I will discuss these below in more detail and show them is a different section of the build when I do them. So back to the images. The stand top has been painted and bolted to the stand. It is kind of hard to tell but there are four bolts that are counter sunk into the top. These are to clear the struts that will go across the table top. As a side note, The image above with the spots... I thought was a dirty camera lens. But after cleaning it and having the same issue, I discovered with a little help of my son Mike, what we are seeing is fine dust particles in the air where we were trying to dust things off to get a better picture. So we let the dust settle and took a couple more. Sure enough, that was the cause of the mysterious spots. Go figure!!!
How I plan to finish the stand
You notice that there has not been a shelf laid in the bottom section of the stand. My goal is to take an old aluminum computer rack and cut it down. Then mount the parts in the stand so I can mount a computer and other hardware in it proper. Once I get that in there to my satisfaction, I will put a shelf on the reminding section of the bottom to hold a small shop vac and perhaps close in the sides. I have not really decided yet. I will cover these additions in a different section of the build log. But as far as chapter one of the book, this is where I end with it. I will be starting the build of the Y-Axis members next.
The feet that we made using the shock bushings didn't work as well as I had hoped. The rubber was a little too soft and would allow you to grab the machine and shake it. Now to be honest, some of the movement was coming from the stand. Hind site is a beautiful thing. Had to do again, I would have made it from 3/16" or 1/4" angle for the weight and rigidity. But there are things to do that will rigid the stand up nicely. Now as far as the feet are concerned, I had two choices. I could have replaced the rubber on the bottom of the feet with some conveyor belt material, OR ... I could use the feet from a Bone Densitometer that I salvaged when one was being replaced at my work place. I opted to use them, it would be quicker. Lastly, I have to say, the machine is quite heavy and lifting one side so the feet could be replaced was hard on the hands. But anyway, the picture shows one of the new feet added to the machine.
See you in the next section ...
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.
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