I bought these two items from a tool store which was closing down several months ago. It’s an aluminium disc, which has a tapered thread on it, and was meant to fit on a tool system or motor which is not available anymore, and there is not much information about. It also came with a sanding disc which isn’t as sticky as it probably once was.
I realised I could attach this to the lathe, so after sticking a Velcro backing pad and sanding disc to it, I placed it directly within the jaws of the lathe chuck but I wasn’t too happy doing this. Even though the chuck came with a wood screw which can be clamped within the jaws, the aluminium is softer then the jaws and over time I could imagine this deforming.
I decided to try drill the hole out, and tap the correct thread for the lathe. Alternatively I could use an inexpensive faceplate with a board screwed onto it, but seeing as I had already stuck the Velcro onto the aluminium disc I would carry on with that. I was not exactly sure how I was about to do, as drilling by hand was not an the option and the pillar drill’s throat was too small. In the end I decided to build a large set of button jaws, which you may have seen me make in a previous upload. I will link too at the end of this video.
I had to buy a second hand 3/4 x 16 TPI tap, which was relatively inexpensive on EBay. It was too large to fit within the drill chuck on the tailstock, and I had to angle-grind the corners. I used 18mm blacksmiths drill bits to open up the tapered hole before taping, and later a 19.5mm bit for the reason I will explain.
The chuck and faceplate on this lathe had a small recess where the thread has been cut away. I mimicked this, so that the back of the aluminium disc could be tightened until it was touching the flange or bearing around the head spindle. I assume this is designed like this because there is always some movement between male and female threads, and this avoids using the thread pitch as a reference.
The large disc that I will use as a bed has been lying around the studio for some time now. No one can remember where it came from, but it was too large to make a sanding disc back from it itself. I also had some metal bar around which I lathed the paint off, and cut to the correct size to fit the tool rest clamp. Using two part epoxy I glued the bar in but this was very messy and a bit like changing a nappy, and it took some time to get right.
I cleaned the top of the bed with a flapdisc and sander before testing how square it was. The advantage of a round bed is it could be turned until 90 degrees to the sanding disc, however despite this it did mean it was slanted across the disc. Sanding straight onto the disc would produce a flat edge but any other angles would become skewed. I also don’t have an extraction system set up for this sander, and when the table takes a knock, it sounds like a gong which is quite annoying.
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