Holding your tool securely…

..do not be quick to take offense, for the taking of offense lodges in the bosom of fools…

…is of paramount importance when using a lathe. This lathe came with several devices to hold tools. Here’s a couple…

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The one on the left is holding a knurler. The one on the right looks like it’ll fit on the Cross Slide, rather than the Top Slide, like this one…

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I was quite pleased to find this in the box, especially as it came with four cartridges…

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…each of which are very similar to the ones in use on the Lathes at Axminster…

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At least it’s something familiar now. The cartridges slide out after loosening a cam. This means you can have four tools ready to go. As the tool height adjuster is on the cartridge, there’s also no need to reset that every time; remembering how important tool cutting edge height is.

This is the main body, with the two tool cartridges removed..

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The two hex heads turn eccentric shafts which cause the square Locks to move in and out, helped by an internal spring. To pull the shafts out, one has to hold in the spring loaded Lock…

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…and the shaft pulls out easily…

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There’s a little spring in there…

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The dirty body with Locks, Eccentric Shafts and springs…

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The four Cartridges, one without a tool and the one at front right has a wedge device to secure the tool, a parting off tool, and the one at front left is reversed…

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Showing four securing screws and the height adjuster…

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In this picture, the height adjuster is dismantled. The screw to the left is a depth stop, to secure the large nut once it is adjusted…

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The parting off tool holder has this wedge arrangement…

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All four cartridges were dismantled. On one of them, the threaded rod for the height adjuster was slightly bent. This is what happened when I used Big Hammer to try to straighten it…

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Now I’ve got some cartridge spares. Dang.

Cleaning was in the usual manner. Here’s the team photo (minus the dead cartridge)…

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When I reassembled the body parts, the action felt gritty and grindy, so took it apart again and cleaned up the moving parts. I chucked the shafts in the drill for polishing, or at least taking off the rough spots. The parts seemed to be made roughly, evidenced by the wear all round. Here’s before…

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…and after…

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The height adjuster nuts were given a polish at their business ends, to make the action smoother. This picture shows one finished next to an unfinished one…

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I cleaned up all the bores as well, using a mandrel wrapped with 1500 paper. This is the body reassembled, using some VG68 as lubricant…

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A centre post screws back on to the Top Slide…

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The body is dropped over it and secured with the large nut…

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Reassembled cartridges with tools…

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…and locked into the body…

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This the cam and height adjuster nut in the unlocked position…

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…and in the locked position…

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I’ve still to have a go at sharpening the tools. I’m rereading “The Amateur’s Lathe” by L H Sparey, where information on that sort of thing is abundant.

Next, chucks…

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The Lathe Course

…Know this, my beloved brothers: Everyone must be quick to listen, slow to speak, slow to anger…

Good advice if you’re an instructor!

Bob Rolph is one of the Course Tutors at Axminster Power Tools for the engineering courses and he was our instructor. Amongst screaching noises and burning smells, he certainly manifested the above qualities!

Mrs Linn and I arrived a few minutes late as we lingered over breakfast at Pestoller House Bed and Breakfast in Axminster, talking to Adrian and Caroline, the hosts. What a lovely place they have! Everything just as you like it. They’ve really thought through what makes a good B and B.

At APT, they have a fantastic set up for teaching. They have a central break out area surrounded by four classrooms. Two for woodworking machines, one for routing and one for engineering.

In the engineering room there was five lathes, clean and ready to go. Here’s a picture…

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What surprised me was how quickly the clean machine became messy. Bits of metal and oil went everywhere. The black shield behind the lathe certainly proved necessary.

Bob went through Safety first. Always wear eye protection and use the guards on the machine. No droopy cuffs, ties, long hair or beards. This isn’t prejudice against corporate drone/hippy crossovers, but just means those things should be tied back.

Next he went through some maths. Yes, maths. Much to Mrs Linn’s disgust (she would love a world without maths) there are some calculations to be done. This is just to find the correct rotation speed for a given diameter of metal rod. Basically, the smaller the diameter, the higher the rpm. Also, if you want to reduce the diameter by an amount, you move the tool inwards by half the desired amount. D’you know, I spent a good half hour – with many attempts at diagrams – trying to explain why to Mrs Linn. Eventually, I had to have extra beer…

First we learned to set the cutting tool to the correct height. It must be exactly on the machine’s axis. Too low and it leaves a nib in the centre; too high and it doesn’t cut properly and can overheat.

Next, we learned to “face off”, which means putting a metal rod in the chuck and causing the tool to move inwards across the end, squaring the end of the rod to the axis. This is only a 0.5 mm shaving.

Then we turned the rod to smaller diameters. We bored a hole in both ends and tapped one of them.

We took a second piece of rod and turned that to precisely to fit in the holes of the first piece; one end with a screw, one end plain.

Finally, we “knurled” the middle portion.

This is The Thing we ended up with…

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One end smooth bored…

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…and the other end tapped…

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The smaller piece was threaded to screw into the tapped end…

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The marks on the smallest diameter of the main piece were caused by me forgetting to support the end opposite the chuck whilst knurling. The pressure of knurling was trying to pull the whole piece out of the chuck’s three grips, causing the marks.

On the smaller piece, the end opposite the threaded end was turned to a precise piston fit…

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The fit is so tight it feels like pushing against a spring to get it in and it pops when you pull it out. It was all quite satisfying.

Bob finished the two days by showing us how to sharpen the tools on the grinder.

Here’s a picture of the knurling tool, which impresses the criss cross grip into the middle of The Thing by brute force…

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A tool cartridge with a tool in it…

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A comparison picture showing the similarities between a modern lathe and a 66 year old lathe…

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The key components haven’t changed much in all these years. What has changed is how the speed is controlled. The modern lathe; easy to operate precise electronic control. The old lathe; pulleys, belts and a gearbox.

We had great fun and I thoroughly recommend the course.

Big Bad is doing his best at the moment to delay things, but I’m cleaning up a tool holder and a chuck this week. A few bits and bobs after that, then maybe we can have a go at cutting something?