Monday, January 1, 2018

Shoulder Hydraulic Part 2

In my last post I showed how I did the round parts of the shoulder hydraulic. In this post I will show how I did the square parts which mount it to the horseshoe.


The first step was to cut a piece of wood to the finished dimensions of the block. The top of the block is rounded over, so to do this I ran the piece on the router table with a large round-over bit to get the slightly rounded top. Once that I was done I could cut the piece into the appropriate sized blocks.


Next I laid out where the hole needs to be drilled in the block.


I drilled the hole on the drill press. I made a fixture to hold the piece while it was being drilled but I didn’t get a picture of it.


These pieces can then be slid on the ends of the round part and glued in place. Here is the completed shoulder hydraulic.


Sunday, August 27, 2017

Shoulder Hydraulic

The next piece I needed for the shoulder was the shoulder hydraulic.


I made this is three parts, the round central shaft and the two blocks at either end that hold it to the shoulder. To make the shaft I turned to a pretty specialized piece of equipment. This is a Unimat mini machine lathe. I rescued this one from my father’s basement where it had been water damaged. It took a lot of WD-40, rust remover and scrubbing to get it taken apart and cleaned up. I also got replacement belts from Toms Tool Store. With this tool I could have made the shaft from metal, but I am more comfortable with wood so that is what I went with.


I started with a dowel that matched the largest diameter of the finished part. Using the measurements of the plans I marked the location of each section that needed to be cut. Once the piece was mounted in the lathe I spun the dowel and marked the lines all the way around.


Next I used a couple different cutting bits to cut each section. I use a pair of calipers to check when the correct diameter had been reached.




Here is the piece after the lathe cuts had been made. For now I did not cut off the ends because I needed to put it back in the lathe later for one more cut.


The hardest part of making this was the knurling around the one section. I tried a couple way to do this and the technique I ended up with produced a pretty satisfactory result. To start I used a CAD program to general a series of parallel lines with the spacing I wanted for the knurling.


I used spray adhesive to glue the pattern onto the part.


I also made a block to hold the part while I was cutting the knurling. When making the cuts the tools are going to tend to come off the end of the knurled area, so I wrapped some electrical tape around the part to protect it.


To make the cuts I started with a straight edge and an X-acto knife. Next I used a sharp dental pick to widen each cut. Finally I used to a diamond shape needle file to get the final size and shape of each cut.


With the knurls cut and the rest of the paper pattern cleaned off I put the part back on the lathe to make the groove in the middle of the knurled section.


I my next post I will show how I finished it.

Saturday, August 12, 2017

Shoulder Buttons

In this post I will show how I made the shoulder buttons. Like a lot of these detail parts you can buy resin or aluminum versions of these online, but one of my design goals was to build as much as I can from scratch.


I started by cutting a dowel into pieces the correct thickness. I then used a centering tool (see my last post) to find the center of the dowel. Normally I wouldn’t worry about the angle between the two lines but in this case I also need them to locate the small holes at the edge so I made sure they were 90 degrees to each other. Finally I marked the centers of the edge holes.


I put the dowel in my clamping jig (again see my last post) and drilled the two edge holes.


I also drilled a larger hole which I will need for the raised button in the center.

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For the button I used a premade wood plug. These were pretty close to what was needed but the actual buttons are a little more cone shaped and these are a more domed.


To fix this I drilled a small hole in the center of the button and attached it to the end of a dowel with a nail. I then used my small bench belt sander to refine the profile.


Here is it looked like before (on the right) and after (on the left).


Here is the button glued into the base part.


Once the glue was dry I drilled the center hole. Here is the final product with a couple coats of grey primer on it.


Sunday, August 6, 2017

Working with Dowels

There are a couple details on R5 that I made using wooden dowels. When making these parts I needed to drill holes in the center of the ends of dowels. This required a couple special tools that I will talk about here.

The first thing I needed was way to mark the center of a dowel. Here is a store bought centering tool that I got as a hand me down. It has a V-shaped slot on each side that you put the dowel into and then mark along the straight edge. You need to mark at least two lines to get the center, but I always mark a third just to be sure that I didn’t mess up one of the other two lines. You can buy one of these from here, among other places.


Another option is to make your own centering tool. This is made with two pieces of plywood glued together at a right angle and a piece of style cut with a 45 degree angle. For this to work properly you need to be sure the angles are as accurate as possible. Be sure the two pieces of plywood are square to each other, be sure the styrene is exactly 45 degrees. This is used the same way as the store bought one.


The second thing I needed was a way to hold the dowel while I was drilling it. To do this I started with a piece of 1”x3” pine and drilled holes for each size dowel I would be drilling. I then cut a slot through the center of the holes with a band saw.


To hold the piece, I put it in the appropriate size hole and then clamped the end of the board which squeeze it tight around the dowel holding it in place. Before drilling the dowel I used the centering tool to mark the center and then used a nail to put a small guide hole at the center.


Sunday, July 30, 2017

Completing the Horseshoes

The next step on the horseshoes was to skin the edges with styrene. I used the same technique I used on the legs, attaching the styrene with a 2-part epoxy. I used some clamps and painters tape to hold it in place and worked one section at a time.


Be careful with the end of the styrene strip that isn’t glued down yet, you don’t want to do this…


Fortunately no harm was done in this case. Here is the styrene taped up all the way around. I left the piece long and trimmed it when everything was dry.


I was having a hard time getting the bottoms of the two square holes clean, so I decided to glue in some pieces of styrene to give the bottom of a pocket a clean finish. The other hole was large enough that I was able to get it smooth with some sanding. Here is the complete horseshoe with a couple coats of white spray paint.


Sunday, July 23, 2017

Horeshoes Continued

A while back I showed how I made the segments for form the should horseshoes.


The next step in making the horseshoes was to glue these up. Once again I build a jig to help with this process. The jig is composed of a piece of plywood with three 2x2’s screwed to it which forms an area that is exactly the size of the horseshoes. This allowed me to stack the four layers and be sure they were perfectly aligned.


I placed the first layer, and then applied a coating of wood glue to the back of the second layer, stacking it in the jig. I repeated this process with the other two layers. Once this was done I screwed a piece of scrap plywood to the plywood which acted as a clamp.


The next step was to cut the pockets into the surface of the horseshow that will hold the shoulder details. This is the process I used to cut them, but I was not entirely happy with the results I got from this. It required a lot more hand working of the cut outs to get them to look good.

I made these cuts using a router with a straight cutting bit and a guide collar. I made  template out of luan plywood that would guide the router. I didn’t want to screw the template directly to the horse shoe so I screwed some blocks down to my workbench in various positions to firmly hold the part and then screwed the template to one of these blocks. Since this was a deep cut I made multiple passes to make the cut.


It’s been a while since I made these so I can’t remember exactly how I did the square holes. Since there is a small hole in the bottom of each one I may have started the hole using a forstner drill bit and the finished it with the router and template. I did make a template to cut both of the square holes with one template.


Once the router cuts were complete I used a chisel to clean up the corners and did a lot of sanding and patching to clean up the holes.

Sunday, July 16, 2017

Leg Skins

In previous posts I showed how I made the layers of the legs. I eventually glued these up to form the structure of the legs. With the legs glued up I decided to skin the edges of the legs with styrene like others have done. With a lot of work I probably could have gotten a smooth surface on the edges, but with the layers of plywood it would tend to crack through the paint, thus the reason for skinning. I decided not to skin the large surfaces of the leg because I felt I could get a nice enough finish without it, but I have seen people who skinned the entire leg.

To start the skinning process I used wood filler to fill any voids in the legs and then sanded everything smooth. I used fairly thin styrene for the skin so I didn’t want any defects in the wood to show through.

I cut a piece of styrene the rough size needed for the bottom portion of the leg. I started with just one side, putting the seam at the very bottom point where it won’t be seen. The piece can be a little bigger the necessary, it can be trimmed afterwards.

To attach the styrene I found the best adhesive was two-part epoxy, I couldn’t find anything else that held as well. I first roughed up the back of the styrene with some sand paper and then coated the wood with a smooth layer of epoxy. Since the epoxy has a fairly short working time I did this in a couple steps. For this part I started with just the side flat area, and then did the angled part as a second step. I taped the styrene in place to keep it from moving while I clamped it.


I firmly clamped it with a piece of plywood between the clamp and the styrene to keep the clamps from damaging the surface. Once that section was dry I moved on to the part that went down the angled part, you can see it sticking out in the picture below.


I used this same process for the rest of the leg. I did the flat side as one piece and cut the groove afterwards. I did a second piece on the slope going up to the shoulder, and the on long piece going all the way around the shoulder. The flats I did with one glue up, but the curve I did little by little so I had  place to clamp it.


Once everything was glued up and dry I trimmed any overhang of the styrene with an X-acto knife and then sanded the edges. There were a few places where the styrene did not adhere completely along the edges so for these I used a toothpick to put in some more epoxy  and taped it down to dry. The epoxy works good for this since any the squeezes out can easily be sanded smooth.