Dave: I haven't counted up the studs, but it must be several dozen at 1/4" BSF and slightly fewer at 5/16" BSF. Fortunately I have both 1/4" and 5/16" collets. Changing the spindle collet yesterday seemed easy enough. Unscrew the nose piece, swap the collet and replace the nose piece. Clearly the more you screw the nose piece in the tighter the collet gets on closing. Presumably the idea is to have the collet just tight enough to grip the work, but no more or the closing fingers might get damaged?

Norman: As Dave says 8BA is no problem. I've also got a 5/16" (8mm) Coventry diehead for the Britan. Currently it has 4BA dies in it, but 8BA is readily available. You can even get new dies for the ME 40 tpi series. As an aside there was also a 3/8" (10mm) diehead, but there are far fewer dies available in this size, so presumably the 3/8" diehead was much less popular?

Neil/Ken: Yes I know, but it's still depressing. Mind you not only will my studs be better I'll have some fancy washers too with a nice chamfer on them instead of commercial stamped out washers.

Regards,

Andrew

Dave,

Thanks for putting me right on changing the collets; that'll teach me to wing it instead of reading the manual first.

Regards,

Andrew

Finally the Britan is paying its way. As part of a set of plastic production jigs I am making for a client I needed 33 spacers, each 80.65 ±0.05mm long, with a 5.8mm hole in each end for a threaded metal insert.

It's long been a PITA facing items to an accurate length on my conventional lathe; face off, take the part out, measure it, put it back, take a bit more off and so on. Things are not helped by having a Burnerd multisize collet chuck, which is not dead length, on my conventional lathe. Due to the design of the jig it is important that the spacers are consistent on length as it controls how the internal parts clamp together. Here are the finished spacers:

The plastic (delrin) is nominally 12mm diameter, in practise it is 12.4mm. I don't have a collet for the Britan of that size, so I made an aluminium split collet to fit a 15mm Britan collet:

One end of each spacer was cleaned up on my conventional lathe. I then fitted the backstop to the Britan and using the adjustment screw crept up on the correct length for the spacer. Once set up it only took about 15 seconds per spacer to face off to the correct length:

I then used a centre drill (left hand) to centre each end:

And a 5.8mm drill, also lefthand, to drill the holes:

The centre and drill were separate operations, as I haven't worked out yet how to cope with the very different lengths of the centre drill and jobbers drill when they are mounted together. I'm really pleased with the operation of the Britan, it made what is normally a tedious and long winded job very simple. Doesn't happen often, but definitely one of my better buys.

I quoted a fixed price to make the jigs, so I'm feeling rather smug that these parts took a lot less time than I budgeted. Tomorrow I'll make up a simple adaptor to fit the threaded inserts, while ensuring that they go in square.

Regards,

Andrew

I can't dance to save my life; that probably explains why I had a few 'issues' pulling levers in the wrong order. Fortunately none of them resulted in clean underwear being required.

Regards,

Andrew

David,

Thanks for the hint. I can find left hand stub drills with no problem, but nothing for left hand long series centre drills. Any ideas?

Regards,

Andrew

Another first for me, machine tapping on a lathe. I've machine tapped thousands of holes on vertical and CNC mills, but never done so on a lathe; before now. Here's a picture of the setup:

The tap is M3, spiral flute, in a holder with a one way clutch. In other words the holder will drive the tap until it pulls out and disengages the drive, but in reverse it always drives the tap. After a tentative start on slow speeds, 56 and 112rpm, I finally settled on 562rpm for the tapping. The procedure was to start the lathe in reverse, ie, conventional direction for a normal lathe. Feed the tap in up to the preset stop on the tailstock. After another couple of turns the tap holder disengages and the tap spins with the spindle, then knock the spindle into reverse, just hit the reversing lever, no need to stop the lathe. The tap holder engages and reverses the tap out. Job done, takes much longer to write about it than to do it.

It took me less than 45 minutes to thread 32 parts this afternoon, including making a split brass bush to hold the tap, the initial tentative experiments and a few tests with an M3 bolt to make sure that I really was cutting a thread.

The more I play with the Britan the more I like it!

Regards,

Andrew

Hi Dave,

Fun indeed, and being paid for it! I have been very pleased with the way the Britan has helped me do the tasks outlined. They may be simple, but they're a PITA to do on my conventional lathe, particularly for multiple parts.

By not using a centre drill presumably that implies that the twist drill will start true by itself? I didn't try that, although on my conventional lathe it doesn't work.

I assume by 'opp' it you mean doing one operation with one tool on all parts before moving on to the next? If so, that's what I've been doing, as I judged it to be the quickest for these particular jobs, particularly as swapping parts in the collet is so quick. It's the first time I've used lever operated dead length collets, quite a revelation. Some of the operations have been done on the conventional lathe as I judged that to be quicker than setting up the Britan.

It's good to have finally used the Britan for some real work. To paraphrase, it may be a small step for me but a giant leap in my potential capabilities. I've got the metal in stock so I'm looking foward to knocking out studs, nuts and washers for my traction engines.

Regards,

Andrew