As the A Team's Hannibal Smith said "I love it when a plan comes together"

Well it was a pretty productive month. As mentioned I needed to restart work on the steady rests and this time I did both side by side. I would first do a machining operation on the worst casting and then tweak it, or not for the second casting. This worked quite well. So I won't go over all the steps to get to the point where I was ready to bore the holes in the base of the steady rest to accept the two pins required to lock it in place. So the first new thing we did was make the rivet that will hold the upper and lower part of the steady rest together. I decided to do this in two parts after trying a more traditional riveting method first. I decided that trying to actually rivet the pin was harder than making two parts with rivet heads and then forcing one into the other with an interference fit. First we made the the long end of the pin that would go through the entire hinge with a rivet head on one end. The other end would have a hole drilled into it that would accept the other end of the rivet. Here are some pictures showing the part being made in the lathe and then lying for display.

The first picture shows the lathe in the chuck after it was cut to diameter, length and had the head rounded over in shape of a rivet. Final operation operation was to drill a hole in the other end and to do this I needed to make a small sleeve that would go over the rivet body and then secure it in the chuck. The second picture shows this small collet. The slot was cut of course to allow the collet to squeeze the rivet and securely hold it while drilling the hole. The third picture shows the two pieces of the rivet. The smaller piece is a few thous bigger than the hole in the longer body and hopefully with some locktite and the interference fit will be a secure fastening for the hinge. The last photo just shows the long pin in the hinge for trial fitment.

Once this was done we could move on to drilling the two hole for the locking pins. First we set the base unit on the lathe and then carefully scribed a line vertically up the middle of the gap in the lathe bed onto the base of the mill. I then calculated where on this line I wanted to drill the hole. After a slight mis-start on the first base we drilled both of the horizontal holes. I then set the fixture up to drill the vertical hole which would intersect the horizontal hole. I lucked out in both cases and got both holes to intersect with most likely no more than 10 thous error. The Horizontal hole is .470" dia and the vertical hole is .750" dia. The vertical hole goes approx .650" deeper than the horizontal hole to allow room for the pin and a piece of spring. Here are a few photos showing the process.

With the holes drilled out it was time to start working on the pins. Unfortunately I forgot to take pictures of the process so I only have pictures of the final product. We started by using a piece of 5/8" hex bar to make the horizontal pin. I initially machined done the surface of the pin area and once complete cut the whole length off. I inserted the pin side in the chuck and gave a slight rounding over to the head of the bolt. I made two of these and here is a picture of the results.

Next we turned to the Vertical pin. This was made from 3/4" round stock so required very little machining on the section that went inside the base. However the bottom end was turned down to .500" to accommodate the tread that would be cut later on. This smaller dia piece was then tapered up to the .750" size and then cut off so that we would have approx 5/16" left on the shaft after the cross hole was drilled for the horizontal shaft. I then placed the pin in the base and through the horizontal shaft marked where the through hole needed to be. Then prayed to the metal gods and drilled out the cross hole. Miracle of miracles after a little bit of filing it fit like a glove. Once this was done I decided to thread the shaft using the BSC thread dies I had and threaded a 1/2" by 26tpi thread. Once this was down we carefully filled down one side of the horizontal shaft where the vertical shaft crossed it. This would allow the vertical shaft to lower by the amount of material moved on the horizontal shaft due to the pressure of the spring above it. Then when the horizontal shaft is turned 180 degrees it raises the vertical shaft and thereby locks the base to the lathe bed with the assistance of a nut that still needs to be made.  Here are some pictures showing the two shafts and how the interact with each other.

 

Unfortunately when I went out to purchase a piece of steel to make the nut plate I bought the wrong bar stock and will need to pick up another piece on Tuesday. However I did make a temporary nut to try it out. It worked however I am a little concerned that the thread might be to fine a thread for the usage. Once I make a proper nut I will assess the working of the assembly. My worse case will be to make two new vertical shafts and thread a coarser thread on it, most likely 1/2-13tpi. However we'll see how it goes later this week. Even with this minor issue I was quite happy with all the work done. I'm just glad that it worked as expected.  Like Hannibal Smith said " I love it when a plan comes together"

Well that's all for now and we'll see you either end of March or earlier If I get the two units finished sooner.

Harold

Second kick at the steady rest so to speak

Well we're back at it. I've started to machine another steady rest after scraping the first one. As mentioned I had three castings made and therefore I still had two left to work on. This time I started working on worst casting of the three. I think this one kinda shifted a bit as the molds were being assembled so the casting is just a little lopsided. So we placed the casting on  the mill and machined out the bottom section where it will sit on the lathe. This actually worked pretty well so decided that while the jig was there might as well take the same cuts on the third casting as well. From now on  I'll continue making the first cuts on the bad casting and if it works then doing the same work on the third casting. I don't have many pictures as the work is the same as was described in the last blog. I will leave you with one picture that shows both castings sitting on the lathe after their bases had been machined out. I needed very little work with hand files to fit them nicely on the base. Majority of filing was just to knock down the edges of the milled surfaces. The casting to the right is the bad one and will be used on the #39 lathe and the one on the left will be for the #86 lathe.

After I took this picture I did a little more work on the castings and I milled a slot in both where the upper section will fit in and pivot around. So over the next few weeks we'll continue working away at them and we'll see where we are when we write another entry towards the end of February.

All the best and Happy Valentine's day.

Harold