Member postings for Andrew Johnston

If the die is not split it might actually be a dienut, which is not intended to cut a thread, but to clean up existing threads. Either way, cutting a M12 thread by hand with a die is going to take a lot of torque.

Regards,

Andrew

Neil: Let's not beat about the bush; it's a wonderful toy! And I'm really looking forward to learning how to use it. I've already had a client show interest in its capabilities. While I assume that it was originally intended for reasonable volume production, I think it will be useful to me for much lower volumes, even down to 10's. I have a capstan unit for my normal lathe, and it works well, but one big issue is that the saddle position is difficult to control. You need to be at one end of the part for facing and chamfering, and then the other end for parting off. I am hoping that the Britan will make this much easier, so that parted off components have a consistent length, without the need to measure and face the second end as required. I'd be happy if I could produce parts with a length tolerance of better than ±0.004 in one operation, I'd be delirious if I could achieve ±0.002". I had thought of steam fittings, but parts for ships escaped me; good idea! Apart from experimenting, I expect that the first serious use will be to make the studs and washers for my traction engines. I'm happy to use commercial nuts, but I think that a turned washer with a slight chamfer looks so much better than the commercial stamped out washers. And it gives the rivet counters something to check on.

David: Great information on the tool setup; you've also saved me money! For some reason I had in my mind that the tool bits needed to be 3" long, now that I've checked in the manual it says 3-1/4" to 3-1/2". I've got several boxes of tool bits, some ground, some unused, to play with, but it'll be useful to stock up with some more, of the correct length! The 5/16" square bits seem to be easily available, but 5/16" by 1/2" and 5/8" don't seem to exist. Presumably, if I was turning brass for instance, there's no reason why I shouldn't make form tools out of gauge plate? I've already learnt by hard experience that if you don't get the tool capstan rotation right, you ding the tool rest.

I have a supplementry question about tool setting, in particular tool height. I understand how the tool height is adjusted, using the eccentric screw at the back of the tool, but what do you use to reference the tool to centre height? On my normal lathe I just 'eye' it up against a centre in the tailstock. Can one do something similar on the Britan, or is there a better way?

It's interesting that tipped tools were available. Presumably there's no reason not to use insert tooling? A 5/16" shank is pretty close to 8mm, so the smaller tool shanks could be adapted.

Aaaaah, I've just had to nip into the workshop to have a quick play, just for the sheer pleasure of running the spindle up and down in speed, forward and reverse, and watching the hydraulic feed working. Simple pleasures for simple minds, that's me.

Regards,

Andrew

Oeeeer, I don't think you can get Coventry die sets that small. The smallest I've seen is 10BA, for a 1/4" diehead. The Britan did come with adaptors for conventional split dies and taps. The adaptors are quite clever, they rotate freely once the thread depth is achieved, but when the spindle is reversed they lock up and back the die/tap out. I guess the main problem with threads this small is stripping of the thread during manufacture. That is probably why the Coventry die sets don't go that small.

Regards,

Andrew

Ady1: I downloaded the manual and parts list a while back from the company that now owns the rights - Andrew Engineering. Nothing to do with me! I also got an original paper manual with the machine. It is rather an odd manual; it's printed, which is a step up from the old wonky typewriter ones of the 1960s and earlier. However, it goes into a lot of detail on some things, but has no overall specification nor an introduction to controls and features. I did buy a copy of the Britan information on CD some years ago from www.lathes.co.uk, but the CD has gone soggy and the files are now unreadable.

Sam: Thanks!

Dave: Thank you for confirming that I've understood the taper setting mechanism, and the advice on using it. I feel confident that I can experiment with it now without fear of breaking something. It's going to be an interesting challenge to work out the best way of machining parts. Even a quick look at the manual shows that one correctly shaped tool can form several features at once. It clearly requires a different way of thinking.

The small company I bought the lathe from were very surprised at the interest they got for the Britan. I'm not, numerous companies have them on plant lists, so I assume there are quite a lot still in commercial use. Even the client who stopped by today to discuss an urgent design and machining job showed some interest in its potential.

Regards,

Andrew

Who knows what the casting is made of then; probably somebody's aluminium saucepan, with the odd park railing thrown in for good measure! We had an engine failure on our Tiger Moth which was caused by the valve rockers falling off one cylinder when the cylinder head casting suffered a progressive fatigue failure.

Regards,

Andrew

It's just typical; I spend all my time at junior school struggling to learn £sd and hundredweights, stones, pounds and ounces etc, and then the government goes and changes it all! It's a shame I didn't keep a ten bob note, but somewhere I do have a nearly new crisp one pound note.

Sam: I think you have it nailed. Now I see that the manual does mention air in the hydraulic lines, and gives a procedure for removing it. I had a go but don't think I did properly. When the lathe is in its final position I'll treat it to a new fill of hydraulic fluid and try the procedure properly.

David: Thank you so much for the guidance on the speed and direction levers and the high/low clutch. There's quite a lot of 'fluff' inside the works, so I intend to give it a good clean and then look at the clutch. The clutch does work, it's just rather stiffer than I think it should be. You're no doubt correct that it just needs a clean and oil. I hope you don't mind me asking lots of questions? Where abouts are you based?

I now have another operating question. The manual states that the turning tool capstan unit can be set to turn either two different tapers, or one taper and parallel. Here's a picture of what I think are the relevant controls:

I see how the item labelled 'screw' can be used to swivel the capstan unit to enable a taper to be cut. There's also an indentical screw on the back of the capstan unit. What isn't clear to me is how you get two tapers, or one taper and parallel. All I can think of is the the front and back screws are set differently and the item marked 'handle' is used to change between the two limits. Is this correct?

Regards,

Andrew

Edited By Andrew Johnston on 25/10/2012 11:48:08

John: There are definite advantages to the smaller machine tools! I don't know how much the lathe weighs, as unusually the manual has no specification page. However, I estimate somewhere around 500-600lbs; so not particularly heavy.

Rob: Well I certainly don't envy you having to move machines over a 2ft drop. When picking up the lathe we had to negotiate a 5" step up, but we did that with some planks and feathered boards to give a smooth transition.

Ady1: I know I'm a lucky woofer. The lathe does seem to be particularly well equipped. As far as I know most of the collets and tooling are specific to Britan, so there's little point in buying one without tooling, as you sometimes see on Ebay.

David: Indeed it is the 1-1/4" version. Looking at the serial number it seems to be a model E Mk1A. Thanks for the advice on the belts and pneumatics. The bar feed tube is 5ft long; if it has been shortened I can't tell. I think I've identified most of the tooling from the pictures in the manual. It has a good selection of headstock collets, some tailstock collets and quite a few tailstock capstan collets. It's also got what looks like a complete set of self-releasing holders for normal taps and dies, as well as the two Coventry dieheads. The only thing missing which might be useful is a roller box, but it shouldn't be difficult to make one.

The lathe is rather newer than I thought. It still has the round headstock, so early 1970s at the latest according to www.lathes.co.uk. However, the manual I have, which has the correct serial number pencilled on the contents page, also has a price of 75p on the cover, which presumably puts it after February 1971. So I assume that the lathe was new after early 1971. I've never seen a price on a machine manual before, fancy charging extra for the manual!

This evening I've got the three phase wired up and given the lathe a run. It all seems to work, although the low/high clutch seems a bit stiff. Does anyone know if this should be changed with the spindle stopped or running? Along with the clutch and two levers on the headstock there are four speeds available in both forward and reverse. However, the V-belt to the headstock is on a three groove pulley, giving twelve speeds in total. Presumably if the speed range (in blocks of four) needed to be changed this was done manually before production commenced? At the moment the four speeds vary from 56rpm to 1125rpm, so quite a wide range. The manual doesn't mention anything about how to change speeds or ranges.

The pneumatic pump seems to produce air, and the hydraulic capstan feed seems to work, albeit a bit jerky. That may just be because I don't think the lathe has been used much recently.

I'm feeling my way slowly at the moment, trying to understand each feature. Any help or suggestions are most welcome.

Regards,

Andrew

Terry: Ideally you need to use one method or the other. Loctite requires a gap to work properly. Using it with an interference fit would just be a waste of expensive liquid.

Regards,

Andrew

Now that I've recovered I can show what I did yesterday, as hinted at in my post yesterday on the 'What did you do today?' thread. What I did was to collect a new lathe with accessories, and some other tooling.

The day started early (for me) with a trip to collect a hire trailer. First hiccup was that the lights on the trailer didn't work, and the number plate wouldn't stay in place. Both problems eventually got fixed by the company I was hiring from. So then back home, by a different route to avoid the A14 morning rush nightmare, to pick up a pallet truck. Then onto the collection point, in a village about 10 miles away, up a series of rather narrow Victorian streets.

It took about 3 hours to get the lathe onto the trailer. The move wasn't far, but it was up a step, through a narrow door and over a sloping gravel drive. I then drove home, slowly as the trailer towed badly. It seemed to hunt quite a bit and the fuel consumption was awful; much worse than my bigger and heavier glider trailer. Here's a picture back home, and mighty relieved I was too to get there:

It took about 2 hours to the get the lathe into the garage. We had a false start as I had asumed that it would be easiest to take the lathe into the house and then back into the garage. However, we couldn't work out how to get the lathe safely over the big step at the front door. Instead we went in via the garage door. We didn't have to move the shaper, which is why I'd originally rejected that way. However, we did have to take all the handles off the surface grinder and then move the grinder back.

Here's the lathe in more or less it's final resting place, off the pallet truck, but still on rollers, as I need to insert the coolant tank and wire up the three phase electrics on the back before finally setting the lathe in position:

The lathe is a Britan repetition lathe, and came with lots of accessories, including round, square and hex collets, a knurling tool, die and tap holders, lots of left hand drills and a couple of nice Coventry dieheads. A lot of the tooling is special to the Britan, so the lathe wouldn't be much use without it. Here's the tooling, the pneumatic bar feeder and a Wolf grinder, angle plate and big V-blocks that I also collected:

I also collected a few Morse taper drills, some small V-blocks and a dinky internal micrometer, as shown here plus some more bits for the Britan, including spare belts, which is good, as I expect that they're now unobtanium:

Once I've got it up and running all I need to do is work out how to use it, and what I'm going to use it for! At least it should make it easier to make all the studs, screws and washers for my traction engines.

Regards,

Andrew

PS: The lathe and grinder were paid for by cheque, so I suppose we can say this is 'cheque book engineering' at its finest.

Ian: Thanks for the hint, after a short search I've now found the thread containing my results for milling HSS, last but one post:

**LINK**

Looks like I remembered correctly, the finish was much better running fast and hot.

Regards,

Andrew

What did I do today? Too cream crackered to say! But I can safely say I never realised that the Cambridge rush hour traffic was so appalling. I'm glad I work at home for a fair proportion of the time.

Terry: Following on from the suggestion by Chris I tried milling HSS some while ago. i did post the results on this forum, but I can't remember where. I used a three flute uncoated carbide cutter and it worked fine. As I recall the best finish in terms of Ra was when the swarf was coming off red hot. I find that carbide cutters can be brittle when stationary, ie, using them to 'touch off' on work but I don't normally have a problem with brittleness when cutting. It's just a case of getting feeds right and avoiding stepovers around 50%.

Regards,

Andrew

Today's saga unfolded as follows:

1. Overslept

2. Late breakfast plus large quantity of coffee while posting on ME and TT forums

3. Move car out of car port and fill with timber, straps, rope etc. ready for machine moving tomorrow

4. Extract pallet truck from garden shed - replace lawn torn up by dragging pallet truck across it

5. Sweep car port and wash front door

6. Major tidy up in house, clear dining room table of grinding wheels, BSF fasteners, taps & dies and capstan tooling - took hours

7. Fill car with fuel and drive to pick up engine crane I'm borrowing from a mate in case it is needed for said machine move

8. Sort out paperwork for trailer hire, number plate etc

9. Hit the sack

No workshop time today I'm afraid. Going back to a comment in the original post, I'd now be fairly wary of posting pictures of work-in-progress or machining methods on this forum. I'll stick to my build diary on TractionTalk.

Regards,

Andrew

Quite so, a very positive philosophy. Mind you it is interesting to speculate on how my career might have turned out if I'd chosen to do an apprenticeship with W. H. Allens in Bedford (steam turbines and diesel engines), rather than get involved with electronics.

The best thing we can say about school is that I survived, no thanks to some, but not all, of the teachers.

Regards,

Andrew

I was tidying up in the greenhouse this morning and was duty tug pilot this afternoon, so not much workshop time. However I did finish cleaning and assembling the connecting rods for my traction engines. I also had a final clean up in the workshop ready for the new (to me) lathe I am collecting on Monday.

Regards,

Andrew

Brian,

My ER collet holders have flats on the collet holder itself. So one spanner on the holder and one on the nut allows the collet to be tightened without needing a spindle lock.

Regards,

Andrew

I'll second Lampton's analysis, it's a well argued and fair statement.

However, I would take slight issue with the point on spelling and grammar. I agree that everybody makes the occasional error. But it is rather sad that some posts on this forum are so littered with errors as to render the post unreadable.

It's strange that errors in an engineering drawing seem to attract opprobium on this forum, but errors in the written word are seen as acceptable. Both are methods of communication, and if either are littered with errors then it is likely that the message will be lost.

Regards,

Andrew

It's probably a bit late to say, but personally I don't find the lack of a Z-axis readout on my vertical mill to be a problem. I fitted a 2-axis DRO to my vertical mill about 10 years ago; it's probably the single most useful accessory I've bought for the workshop. However, I have no readout fitted on the quill or knee and I don't miss it. I don't normally need to drill to better than ±1mm on depth, which I can set on the mechanical stop quill. For slot depths I use the dial on the knee and a depth mic, which is more than accurate enough. I'd estimate that the ratio of needing an accurate depth reading versus using X & Y co-ordinates for milling and drilling is rather less than 1%.

Regards,

Andrew

I'd guarantee that the mill is at least secondhand. I'm not sure when Adcock & Shipley stopped making horizontal mills, but I'd guess in the 1980s. My Adcock & Shipley 'Bridgeport' manual shows a picture of a 2E looking a bit old fashioned; the manual is dated 1978.

I've had an A&S 2E for some years now; and it has proved to be a very useful machine. There's no substitute for rigidity and horsepower when it comes to metal removal rates; makes the Bridgeport look distinctly wishy-washy. I paid £150 for my 2E, from a dealer; a real bargain. Just because a machine tool is big and/or industrial doesn't mean it has to be expensive.

Regards,

Andrew

PS: I'd refute the comment by MAC on East Cambridgeshire, quite the reverse; but then I would say that as I live west of Cambridge! Despite the best efforts of the 'developers' Cambridgeshire is still quite a rural county.

Dear oh dear, what a lot of curmudgeons.

Andrew

Measuring using a test bar is, initially, only checking the fit of the test bar Morse taper in the spindle. It doesn't necessarily say anything about the runout of the spindle itself. To start with measure on the spindle itself. Assuming that the spindle has a screwed nose, there should still be an axial and radial ground register, right at the headstock. It would be worth checking the runout of those registers.

Regards,

Andrew