I've not had much opportunity to play on my lovely old Barnes 4½ treadle powered lathe for a while. It's a fine old machine, at least a century old, with plenty of life left in it. There are few concessions to making things easy for the user, but a bit of inconvenience is no barrier to someone like me, who's more interested in the pleasure of making something than just having the thing in the minimum time. Here's a general view of it, for anyone not acquainted with the joys of bread and cheese powered metalworking:
So I was pleased when Steve Maskrey got in touch about some non-standard knobs he needed for some of his jigs. As you can see from the sketch he sent, there's nothing odd about them, but they are definitely more robust than the ordinary Chinese offerings from ebay etc.
So, with today a rainy day ideal for gentle exercise indoors, I had a look in my box of bits of brass and found some suitable bar stock. I'd only got about 30mm of the right diameter, but that is enough for the first two knobs. I fitted in the three jaw chuck, drilled the centre and then deepened the hole to 16mm, 5mm diameter.
To prevent any wobbling from poor support, I put a tailstock centre into the hole, then turned the diameter down to the requested 21mm. I then marked off where the shoulder should come, 6mm from the end and turned it down until it looked about right.
The cutting tools are all holding bits of square HSS bar, so it's easy to reshape cutters to suit different cuts on different metals. This brass is nice and tolerant of the cutting edge geometry and let me get a reasonable shape from the natural curve of the cutter.
I parted off for the length required.
I enjoy knurling. This is just a cheap imported tool from Chronos but I like the way it works. Because it clamps above and below the work there's no great strain on anything. The knurls seem to do their magic and join up tidily. I did apply plenty of thin oil. It's best to engage back gearing for this job, which is a simple question of slackening off and shifting a little oily lug inside one of the gear wheels, and shifting a lever to engage the extra gears.
With that done, I tapped the hole I drilled earlier, M6 thread. This is just by hand really, but closing up the tailstock lets me make sure I start square.
As it was a blind hole, I followed up with a bottoming tap - sorry for the blurry photo.
With that done, I parted off as much as I could, and sawed the last little bit. A quick rub on some progressive grades of silicon carbide paper removed all evidence.
I also chamfered the corners, either with a lathe tool or just with a file.
Here's the first one
and in what seemed a much shorter time, a twin.
So I was pleased when Steve Maskrey got in touch about some non-standard knobs he needed for some of his jigs. As you can see from the sketch he sent, there's nothing odd about them, but they are definitely more robust than the ordinary Chinese offerings from ebay etc.
So, with today a rainy day ideal for gentle exercise indoors, I had a look in my box of bits of brass and found some suitable bar stock. I'd only got about 30mm of the right diameter, but that is enough for the first two knobs. I fitted in the three jaw chuck, drilled the centre and then deepened the hole to 16mm, 5mm diameter.
To prevent any wobbling from poor support, I put a tailstock centre into the hole, then turned the diameter down to the requested 21mm. I then marked off where the shoulder should come, 6mm from the end and turned it down until it looked about right.
The cutting tools are all holding bits of square HSS bar, so it's easy to reshape cutters to suit different cuts on different metals. This brass is nice and tolerant of the cutting edge geometry and let me get a reasonable shape from the natural curve of the cutter.
I parted off for the length required.
I enjoy knurling. This is just a cheap imported tool from Chronos but I like the way it works. Because it clamps above and below the work there's no great strain on anything. The knurls seem to do their magic and join up tidily. I did apply plenty of thin oil. It's best to engage back gearing for this job, which is a simple question of slackening off and shifting a little oily lug inside one of the gear wheels, and shifting a lever to engage the extra gears.
With that done, I tapped the hole I drilled earlier, M6 thread. This is just by hand really, but closing up the tailstock lets me make sure I start square.
As it was a blind hole, I followed up with a bottoming tap - sorry for the blurry photo.
With that done, I parted off as much as I could, and sawed the last little bit. A quick rub on some progressive grades of silicon carbide paper removed all evidence.
I also chamfered the corners, either with a lathe tool or just with a file.
Here's the first one
and in what seemed a much shorter time, a twin.
