Hi H&B.
Got the measurements you asked for earlier, but one thing I will say before going anywhere is that none of these are critical. In fact the one I made is a little bigger than some. The reason being I made it to fit two lathes.
I had downloaded a PDF of a plan of a ‘snake’ (Capt. Eddie's steel snake) from the USA, the guy who first got me interested was Wayne Bower's posts in a USA forum, but I arrived at my sizes and design by constructing a mock up in MDF.
I used a 2 morse taper from Chronos supplies, with a soft stub end, and threaded 3/8” whitworth for a draw bar. I used bright mild steel at 25mm square, and 10 x 25mm flat. Again the design to use it anchored at the tailstock was because it was to fit both my lathes. What a lot of people have done is construct a centre height post for the rig to swivel on. Then of course you would need a different anchor post for each lathe.
I also used 8mm bolts with nylock nuts. I was going to use bronze bush bearings but after reading that the original had no bushes just steel to steel I decided to try that first. I suppose with the facilities of a machine shop the ideal would be to mill out the solid bars and insert thrust bearings at the pivot points. I ain’t got that facility.
I cut a small section of 25mm square and turned a small stub on one end using a HSS scraper in my lathe. I then drilled a matching hole in the end of the 2MT stub. This was just to hold the two square and central while I welded them together.
All the steel was cut now, 2 pieces of flat bar @ 255mm long, 1 piece of 25mm square bar @ 270mm long. Plus 2 pieces of 25mm square x 150mm long for the bar carriers. I then marked and drilled all the holes for the bolts, I was lucky, I had an old drill bit which left a finished hole that was a neat sliding fit for the bolts. Then mounted the carriers pieces on my big lathe and drilled the central holes out to take, 1/ ½” hollowing bars, and 2/ 5/8” hollowing bars. I then drilled and threaded two holes in each to take the hex key locking screws for the bars.
I put it all together and found that it swivelled fine with very little play, but as soon as you tried to set the lock nuts one or another of the pivots would seize up. Rather than get too involved, as I don’t really have any machining facilities, I bought a piece of 1”dia. ‘Oilon’ rod, drilled a 8mm hole down the middle, and using a parting tool turned off 1mm thick penny sized washers. All the pivots where treated to these and worked a treat and I can now set some tension on the lock nuts while still having full movement in all pivots.
I have used it twice now, it takes a bit of getting used to after hand hollowing, but as with anything that will come with practise. My next job is to make a overhead frame and fit a laser pointer so as I can see where the cutting tip is while inside. When I get this finished I will put up a couple of photos if it will help.
My next task at a much later date is to make a captured ‘D’ hollowing rig then I can see which is the best for me. Also they are a lot easier to construct.
Hope this has helped so you can get one set up for yourself. If I can do this with my lack of experience and only a wood lathe, I’m sure your ‘metal’ mate will be able to make a cracker for you.
If you want more photos let me know.
Got the measurements you asked for earlier, but one thing I will say before going anywhere is that none of these are critical. In fact the one I made is a little bigger than some. The reason being I made it to fit two lathes.
I had downloaded a PDF of a plan of a ‘snake’ (Capt. Eddie's steel snake) from the USA, the guy who first got me interested was Wayne Bower's posts in a USA forum, but I arrived at my sizes and design by constructing a mock up in MDF.
I used a 2 morse taper from Chronos supplies, with a soft stub end, and threaded 3/8” whitworth for a draw bar. I used bright mild steel at 25mm square, and 10 x 25mm flat. Again the design to use it anchored at the tailstock was because it was to fit both my lathes. What a lot of people have done is construct a centre height post for the rig to swivel on. Then of course you would need a different anchor post for each lathe.
I also used 8mm bolts with nylock nuts. I was going to use bronze bush bearings but after reading that the original had no bushes just steel to steel I decided to try that first. I suppose with the facilities of a machine shop the ideal would be to mill out the solid bars and insert thrust bearings at the pivot points. I ain’t got that facility.
I cut a small section of 25mm square and turned a small stub on one end using a HSS scraper in my lathe. I then drilled a matching hole in the end of the 2MT stub. This was just to hold the two square and central while I welded them together.
All the steel was cut now, 2 pieces of flat bar @ 255mm long, 1 piece of 25mm square bar @ 270mm long. Plus 2 pieces of 25mm square x 150mm long for the bar carriers. I then marked and drilled all the holes for the bolts, I was lucky, I had an old drill bit which left a finished hole that was a neat sliding fit for the bolts. Then mounted the carriers pieces on my big lathe and drilled the central holes out to take, 1/ ½” hollowing bars, and 2/ 5/8” hollowing bars. I then drilled and threaded two holes in each to take the hex key locking screws for the bars.
I put it all together and found that it swivelled fine with very little play, but as soon as you tried to set the lock nuts one or another of the pivots would seize up. Rather than get too involved, as I don’t really have any machining facilities, I bought a piece of 1”dia. ‘Oilon’ rod, drilled a 8mm hole down the middle, and using a parting tool turned off 1mm thick penny sized washers. All the pivots where treated to these and worked a treat and I can now set some tension on the lock nuts while still having full movement in all pivots.
I have used it twice now, it takes a bit of getting used to after hand hollowing, but as with anything that will come with practise. My next job is to make a overhead frame and fit a laser pointer so as I can see where the cutting tip is while inside. When I get this finished I will put up a couple of photos if it will help.
My next task at a much later date is to make a captured ‘D’ hollowing rig then I can see which is the best for me. Also they are a lot easier to construct.
Hope this has helped so you can get one set up for yourself. If I can do this with my lack of experience and only a wood lathe, I’m sure your ‘metal’ mate will be able to make a cracker for you.
If you want more photos let me know.
