Horseshoes Part 2

In my last post I showed how I created the the tempalte for the horeshoes, in this post I will show how I used the template and a pattern cutting bit to cut the actual parts. The first step was to cut a series of blanks out of 1/4” MDF and to trace the pattern on to them.

I then used the traced lines to rought cut the parts on the bandsaw.

Next I screwed the template to the first of the blanks. The template doesn’t need to line up perfectly with the traced lines as long as there is wood from the blank sticking out all the way around the template.

Cutting MDF puts out a lot of fine dust so I wanted to take some precautions before I made the cut. I used some cardboard to make a dust catcher that extended all the way over the cutter. I cut a hole in the back of the dust catcher to put the hose from the shop vac and tapped everything down to the router table. Even with this I still used a dust mask while making the cuts.

In my post on cutting the leg parts I talked about the importance of using a guide pin to start cuts on a router table. In this case I found the pin was really getting in way so I chose not to use it. If you don’t use the pin you just need to be very careful when you start the cut. With everything setup I cut all the pieces.

The final operation I did on the horeshoes for now was to form the ridges that are along the inside edge. To do this I used a pattern cutting bit in the router table just like I did to cut the shape. The difference for the ridges is that I replaced the bearing on the bit with one that was slightly smaller the the diameter of the bit.

I then set the depth of the router so the cut will be exactly half the thickness of the horeshoe pieces. Since the groove is only half the thickness of the part the template isn’t needed, you can just run the pieces without it and you will get perfect groove along the edge.

When stacked together you get the ridge effect.

On the horeshoe part nearest the leg I made this cut all the way around the piece. This provides the groove that is between the horesehoes and the leg frame.

Horseshoes

 

The next element I worked on for the legs was the shoulder horseshoes.The horseshoes attach to the outside of the leg frame that I have been building in my previous posts. The tricky part of making this component is the ridges that you can see along the inside edge of the horseshoe. There is also a groove between the horseshow and the main part of the leg.

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Most people make these using eight thin layers stacked together. The even numbered layers are made a little smaller on the inside then the odd numbered layers so you get the groove effect. I took a slightly different approach. I made each horseshoe out of 4 layers of 1/4” MDF and then used a router to cut the groove on the bottom side of each piece.

To cut the shape of each layer I went back to the router table and a pattern cutting bit, so just like with the leg frames we need a template to start with. I started with a printout of a full size template from the plans which I glued to a piece of 1/4” MDF that was cut to the exact width of the part.

To make the outside cut I went back to my router table circle cutting jig that I used for the body frame components. The cross slide slot on the router table was to far from the bit for this cut so I attached a thin piece of plywood to it to get it close enough.

To make the inside circle I used a circle cutter mounted in a drill press. Cutting MDF generates a lot of dust so I clamped the hose of my shop vac as close to the cutter as possible and wore  dust mask. I also firmly clamped the piece I was cutting in place instead of trying to hold it.

For the straight cuts on the inside I used the table saw.

I made the angle cuts that lead into the center circle on the band saw. There was really no way to guide this cut so I carefully did it freehand. The final cuts were the angle cuts on the bottom, I made these on a miter saw. Here is the final template.

In my next post I will show how I used this template to make the actual parts.

More Leg Work

The final operation I am going to do for now on the leg framework is to cut out the inside of the middle layer. There are two reasons to do this. First it reduces the weight of the let by a little bit. Second, if you plan to motorize the feet, it provides a place to run the wires. The cutout of the shoulder also provides some space for the leg mounting hardware.

On the 3/4” center layer I marked a line 1 1/4” in from the edge of the leg. It wasn’t necessary to follow all the contours of the edge, 1 1/4” provides enough clearance all the way around. The line goes right to the end of the foot leaving an open space to run wires if you want to.

Before making the cuts on the band saw I drilled some holes at key points to make if easier to turn the piece.

Here is the final piece temporarily pinned to the inside layer. This cutout will not be seen so the rough cut it not a problem.

Leg Pockets

 

Where the legs meet the shoulder there is a detail feature that goes into a pocket on both sides of each leg.

This pocket is easier to cut out before the layers of the leg are assembled. To make these cuts I used a router with a guide collar and a template. I stared out by making a template out of a piece of scrap 1/4” MDF. The cut out on the right is the actual template.

The shape is pretty simple so I just laid it out based on the measurements in the plans being sure to add the distance between the edge of the guide collar and the edge of the bit to the measurements so that the template cutout is slightly larger then the final size of the pocket. Since the shape has some tight corners I used the smallest possible router bit, but it will still require some manual cleanup in the corners.

With the legs temporarily assembled I marked the location of the pockets. These lines will be used to align the template.

Next I screwed the template to the inside surface of one of the leg side pieces. The cut does not go all the way through this piece so I adjusted the router for the correct depth and then made the cut.

The center layer is cut the same way, but I put a scrap piece of wood under the leg piece because this cut needs to be all the way through.

With the legs again temporarily re-assembled you can see the finished pocket.

Leg Guide Pegs

The next thing I did on the legs was to drill holes for guide pins. This isn’t strictly necessary, but it will help temporarily hold the legs together while I do other work on them and will also help align them when I go to do the final assembly. I started by drilling the hold in my template, one at the top and two at the bottom. I have seen people do more pegs but I thought this would be enough.

Before drilling the holes I made sure that I marked all the leg pieces with which leg they go to, left or right, and which layer they are, inside or outside. In theory if you are very accurate in drilling the holes the pieces should be interchangeable, but I am not going to take that chance. I used this template to mark the holes on the 3/4” center layer of the legs and drilled these holes all the way through. I used a Forstner bit for this which gives a nice clean hole with a flat bottom which will help for they areas where I don’t want to drill all the way through.

Next, I put the middle layer I just drilled on top of the outside layer and used the drill bit to mark the location of the holes.

I drilled the bottom two holes all the way through since there is that small outside ankle layer that will cover them. The top hole I only drilled part of the way through since the hole would be see if I went all he way through. Next I used the middle layer to mark the inside layer. When you do this, remember to flip the middle layer over so the surfaces are together the same way they will be when it’s assembled. As I said earlier, if everything was measured perfectly this wouldn’t make a difference, but I prefer no to take that chance. Just like the outside layer the top hole on the inside layer should not go all the way through, but the bottom two can since they will be covered by another small ankle piece.

I drilled the bottom holes into the outside ankle piece so it could be pinned in place, but the inside ankle layer is so thin, I chose not to drill the holes in it.

Once all the holes were drilled I measured the depth of  the holes and cut dowel pins for each hole.

Leg Structure Part 3

 

In my last post I showed how I cut out the three main pieces of each leg. In this post I will cover a few more of the details of the leg body.

The first thing thing that needs to be done is to cut the point off the middle and inside layers of the leg, leaving only the outside full length. I did this by simply measuring the length and then cutting it off on a miter saw.

Next, two small layers of the ankle need to be made. The outside layer, on the left, is made out of 1/2” plywood. The inside layer, on the right, is only 1/4” thick so I made it from a piece of MDF. I could have cut these on the router table like the other layers, but they are pretty simple shapes so I just traced them from the template, and cut them on the table saw and miter saw. For the rounded end I made a rough cut on a band saw and then finished it on the drum sander.

Leg Structure Part 2

 

In my last post I showed how I created the template to cut the layers of the leg frame, in this post I will show how the cuts were made. The first step was to layout how the pieces will be cut from the plywood and trace around each piece. Since the legs are wider at the top then at the bottom you can get them a little closer together by alternating directions.

The next step was to rough cut them on the band saw to make the pattern cutting a little easier. I started by just cutting between them to separate each piece. I then drilled some holes at the bottom of the shoulder on each side to make it easier to make the rough cut and then cut close to the line on a band saw.

Once the pieces were rough cut I screwed the template to one of the pieces. The template doesn’t need to line back up perfectly with the trace line as long as there is wood sticking out all the way around. I attached the template with two screws. Since only one side of the outside pieces will be seen I won’t even need to patch these holes.

I made the pattern cut in a router table with a small pattern cutting bit. Before making the cut the height of the bit needs to be set carefully so that the bearing runs along the edge of the template and the cutter goes the full height of the plywood. When you are switching between cutting he 1/2” and 3/4” pieces, don’t forget to reset the height! I forgot to do this when switching from a 3/4” cut to a 1/2” and took a chunk out of both my template and the leg piece.

When making a pattern cut it is a good idea to use a starting pin. This gives you something to hold the piece firmly against as you bring it into the cutter. Without it the piece will tend to kick out when you first touch the cutter.

 
With everything setup the cuts go pretty quickly.