The Shop > Tools
Home-brew 120mm rotary table
fatal-exception:
Wow! What a nicely planned and executed project! Congrats! :D
Ray:
:thumbup: :clap: :bow: Wow Arnold. That is some machining. Great job. I want one. My Birthday is coming up (again) this year. hint, hint.
Really, that is a very nice rotary table and you did an outstanding job on it. Hope it serves you well.
Ray
rleete:
How bad is it going to hurt when he miscalculates and puts a divot in that finely machined surface?
I could never make something so nice, I'd be afraid to use it!
arnoldb:
Thanks Benni :beer:
Cheers Nick :beer: - it gets used all the time, and has gotten dirty - and a spot of surface rust :Doh:
Dave & fatal-exception - Thanks gents :beer:
:beer: Cheers Ray - I guess you'll just have to bite the bullet & make your own birthday present :D
Rleete, it's a lot of fun to spend some time to make a good-looking tool and then use it; it makes shop sessions much more rewarding :thumbup: . Fortunately no divots in it yet; in fact, I'm a bit anal when it comes to that sort of thing, and not one of my machines or vises have markings from tool overrun. The markings visible on the 3-jaw chuck jaws was done by a previous owner...
05 June 2010
While the RT is pretty much finished (just needs a tear-down for cleaning, a quick lap of the table to the base with some grinding paste, and (maybe) some paint), I do need an adapter to mount my lathe chucks on it. This is not much of a build; it must just be made accurately, and easy to mount on center on the RT (where I'll most likely use it most of the time), but also off-center if need be, as I have some ideas of machining operations where this might be very beneficial.
My raw materials were running a bit low, but I had ~5 meters of 60x10mm flat bar left - so a bit of that was fine for the chuck adapter base. I was pretty much out of ideal round bar for making the nose for my screw-on chucks; the only bit I could find was not quite as large in diameter as I would have liked, but it had to do.
The bit of flat bar with 6mm slots milled in it for clamping to the RT, centered in the 4-jaw for facing and boring a hole in it:
It's chucked with the jaw edges - not because the slots would interfere, but to be able to use the lower parts of the jaws to keep it flat on the surface of the steps on the jaws.
I then faced the plate, and drilled and bored a 25mm hole in it, with a good chamfer on the face edge of the hole. Then I turned the bit of rod I have to _just_ clean off the crud on the OD, and then turned a section on the front down to match the hole bored in the plate with a fairly close under-size fit (0.02mm / 0.0005" smaller) I could have gone for a press fit, but rather chose to silver solder this joint - hence the bit of "looseness":
I didn't go for nice finishes on this; the visible parts will be turned down further and the rough finish at the plate end will help wick the silver solder through the joint.
Then I fluxed up both pieces, and placed two bits of silver solder on the plate. The plate is suspended on two bits of fire brick, so that I can heat the joint from the bottom with the oxy-butane torch; with the solder on top and the heat coming from the bottom, the solder would want to flow down into the joint - towards the flame:
These are big bits of metal for my small torch, so I set my little butane "plumber's" torch to heat the top bit of rod to get some heat into it without the flame directly playing on the flux, and played the oxy-butane torch with a good blue flame on the bottom. It still took about 3 minutes for the flux to start to flow, and another minute after that for things to reach enough heat for the solder to melt and flow. The rod bit dropped down when the solder melted, with nearly no solder appearing at any of the edges of the joints, so I used just about the right amount :
I couldn't be bothered to pickle that lot after soldering; when it cooled down to black, I just shoved it under a running garden tap to cool down. Very little to clean up, and most surfaces will be machined again...
06 June 2010
I started by turning a ring from some scrap HRS rod - for a light push fit into the "register" hole I bored in the RT's table. Here, it's done and I'm about to part it off:
The ring's purpose will become clear later...
Then I chucked the assembly I made yesterday in the 4-jaw, and roughly centered it - checking that I would need to remove a minimum of metal from the bottom to face it. I then faced it, drilled and reamed a 12mm hole through the center, and bored out a section to fit the ring made earlier, but with the ring a slightly tighter push fit; easily removable, but not inclined to fall out on its own:
Next I cheated a bit. The workpiece has to be accurately turned around and re-mounted to keep both concentricity and axial alignment to the mounting face. I know that my lathe's tailstock and drill chuck is VERY close to perfect alignment with the spindle - less than 0.005mm out on offset, and extremely accurate in line - I can't even measure this. So instead of setting the job up in the 4-jaw and centering it, I mounted the face plate, and with a bit of 12mm silver steel chucked in the tailstock, used it to mount the workpiece to the face plate. No mess, no fuss, and as well aligned as I could have made it with the 4-jaw; just a LOT quicker :
Then I proceeded to face this side of the mounting as well; not really needed, but does look neater, and then turned a spindle nose replica of my lathe on the front section, leaving a bit of clearance so that a mounted chuck will not come into contact with cap screws used for mounting the adapter to the table. I didn't take photos of the process, as I thought I'd just link to a similar adapter I made when I built my collet chuck Turns out, back then I forgot to take some photos.
This was the end result of the operations:
Just for fun, I put the RT to use to clean up the ugly ends of the adapter:
I'm very glad I did this trial run; it uncovered some hiccups - easily addressed once I do a strip and re-assembly of the RT. For one, the pre-load on the bearing is not enough as it is assembled now. I had the grub screws holding the worm and the wheel come loose from vibration, so at next assembly, I'll use some thread locker on them.
This is what the lot looks like with my 3-jaw chuck mounted on it:
:beer: , Arnold
Ed ke6bnl:
I need to make one for my Bridgeport rotary table that was used with a motor drive and I have no scale or dial to rotate the table. Just made a quicky handle to turn it.
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