Britan Lathe – New Lathe Day

[websnailParticipant @websnail]

Hi Andrew,

Re: Small casting with window. yes original Britan part and a pain the bum. It's far too big.We never allowed finished parts to drop into the swarf bin. We made up a small selection of hooks as required and 'caught' the part as it was parted off. If there was no hole in the part, we would start to part off the item and as it got close to fall off, the suds was switched off and your right hand held/supported the part.

Re: Feeds. You might get some more air out of the system by undoing the feed screws carefully all the way and operating the feed lever. Take care, you can get a lot of oil out this way so, hold down the screw as you do it.

Re: Stops. p/off stop, stops the tool going in too far, past centre and hitting things like the hook you're catching parts with. F/cham stop. Controls size of chamfer.

Don't forget to set all the stops. It you don't, you will move the tool too far towards you and the tool in front of it (i.e. the tool below) will smash into the tool rest and a re grind is called for.

Re: Feed rates. two for turning parallel along the lathe axis.

On facing etc. This is where operator skill (art) comes in, You feel the tool cutting and adjust as required. If your are chasing 10ths, take another cut if required to take any spring out. You could face inwards, chamfer and then face outwards, in one hit. Depends on the job and how many tool spaces you have spare.

Re: Maching brass. If you have a choice, use suds. It keeps the stops clean and allows the HSS tool bits longer life. Each time you re grind the tools, you have to re set.

Dave

[Anonymous]

Hi Dave,

Once again thanks for the excellent information. I've now double checked the three phase wiring and moved the Britan off the rollers and into what I hope is its final position:

It is at a rather jaunty angle so that the tool capstan lever clears the bench, bottom right, albeit with a bit chiselled out of the bench leg. I can also still fully open the entrance door, always a plus, and the bar feeder is still able to extend through the door into the hall. At the moment the Clarkson T&C grinder is in the way, but it is only temporarily sat where it is. Once I've moved it, time will tell if the Britan is in the correct place. If it needs straightening up I'll have to make a new lever with a bend in it to keep it clear of the bench. In the bottom right of the drip tray is a small red plastic tea strainer. The previous owner was at pains to explain that this was to catch small parts as they were parted off!

The coolant tank is now in place, so when I get the chance I'll fill it with suds and check that the coolant system works.

I've been playing with the cross slide autolock. If I understand this correctly it is activated for parallel, or taper, turning where the tool doesn't move radially. If the set screw extends within the limits given in the manual the autolock will hold the tool firmly against the tool rest. For facing and parting presumably it is disabled as the tool is selected?

My next question is on profile turning. This is described by one sentence in the manual, which says use a profile plate in place of the standard tool rest. I have a hydraulic copy unit on my normal lathe, so I'm familiar with the basics of copy turning, but inevitably there are specifics that escape me. Does the profile plate replace the standard tool rest? If so, presumably it still needs to support the tool as well as having the correct profile. Can I assume that the profile is produced by having the cross slide in manual mode, held by hand against the profile plate, while feeding along with the hydraulic feed? On my hydraulic copy unit it states that the follower should have the same profile as the tool to ensure a faithful copy. How does this work if the set screw is used as the follower?

Regards,

Andrew

Edited By Andrew Johnston on 02/11/2012 10:39:01

[websnailParticipant @websnail]

My first thoughts on your photo are, can the cover drop down on the right hand side of the lathe? If it can't , pull it out, drop the cover and move it back. You will need to get in there at times. Also don't forget, the suds tank can only be removed from the back of the lathe for cleaning etc.

Re: the cross slide autolock. Yep, your are correct. Method of use, bring tool to start of turn position, hold in position with left hand, right hand moves the lock lever away from you, 'bang', lock on. Start the feed, keep a eye on the progress and as it gets to the stop, cut the feed, hand feed the tool out ( you have to give the autolock a good thump/push, it's a good spring, pull the tool off the work as you do this, until the autolock releases) and depending upon the job, face back in. Never use it for facing or parting off.

It takes pratice to use and you will soon find you have far more control over tools than you do on a normal lathe. Almost everthing is done by operator 'feel'.

Re: profile turning. We only had reason to use it a couple of times. On both ocasions, a 'L' shaped plate was made up and clamped in position, just for the stop to follow. The tool rested on the normal tool rest. This was for a 'long lazy 'v' shape. We would normally use the taper turning or form tool method. Hand or autolock can be used. The set screw, is used as the follower. If you have made up a special turning tool for the form, you might like to make the first cut with a 5 thou feeler gauge under the stop and then make a finishing cut. You have got two feed rates.

Have fun

Dave

[Anonymous]

Hi Dave,

It is possible to open the drop down cover sufficiently to see what is going on. If I ever needed to remove the auxilliary motor pack I'd have to move the lathe; but I'll worry about that if it ever happens. A minor reason for have the lathe at an angle is so that I can remove the coolant tank. Speaking of which, I've now got the coolant running. it took quite a while for the coolant to appear at the nozzle. The previous owner muttered about priming the coolant flow if the lathe hadn't been used for a while, but I'm afraid the technique went in one ear and out the other.

While fiddling with the coolant it occurred to me that the lathe would cause some of the H&S worriers on this forum to have a wobbly. When the coolant wasn't running I opened the drop down cover to see if the pump was running, or if the dog clutch was disengaged. No protection, with the system running there is the belt drive all ready to trap fingers! In the same way, the headstock can be opened while running, exposing the final belt drive.

I'd like to try the lathe on all the speed ranges available by moving the belt that drives the headstock. The only adjustment that I can seen is a screw/spring arrangement that attaches to the motor tray. Is this what I use to move the belt from one headstock pulley set to the next? The manual doesn't seem to mention changing speeds, just how to change the belt when it needs replacing.

Regards,

Andrew

Edit: That's the other thing I was going to say but forgot; the coolant flow seems quite 'weedy'. All the nozzles seem to be open, but the flow is a gentle stream. I was expecting rather a blast of coolant?

Edited By Andrew Johnston on 03/11/2012 12:07:01

[websnailParticipant @websnail]

Hi Andy,

Re: side cover. We used to disengage the dog clutch on long sud free runs. Sometimes, the air pump tufnol 'flapper' gets stuck and needs to be freed off but not as in your case, you are not using the bar feed.'

Re: Priming the coolant. I kept a tin (old baked bean tin) full of suds and a brush for when full flood' suds was not required/possible. Then I always had some suds to prime the system. Power on the lathe, turn on the valve on the head stock, no suds? curse. Switch off lathe, undo valve screw fully, pour in two thirds of the can, get ready to screw back the valve and at the same time, hit the power, suds! Re fill can.

If the filter in the suds tank was blocked, you can blow compressed air in the same way. Don't go mad or you will make a mess all over the floor. Yep, done that a few times. On a good system, the suds flow will go 2 or 3 feet above the headstock. On a weak one, only a few inches. These pumps can be improved if too tired but that's another story, On the spray bar, we drilled out the holes for more flow and used sticky tape to re block the right hand end holes as the job required i.e., no need for full spray bar if the job is only 10mm long!

Re: H&S. Your lathe was designed in the days when common sense was common. In use, it's hard to lift the headstock cover with your left elbow on it. Like all manual operated machine tools, care is required.

Re: Moving headstock belt. Right, the belts are under the tension of the electric motor and the whole lot hangs on the main spindle. The screw/spring is the tension adjust.

To change the top belt, I would get a steel bar around 6 foot long (and either a block of wood or another guy) and lift the motor a couple of inches and pop the belt off the motor pully. Lower the bar. This then makes it easer to man handle the belt off the pully on the top spindle etc. Don't forget, If you change the lower belts, they must be done together as a matched set.

You will note that this far from a fast change. We hardly ever had to do it.

Regards

Dave

[Sam StonesParticipant @samstones42903]

To Andrew and Dave (websnail),

Although I have never seen a Britan lathe (other than in the photographs), and am now too old to even contemplate becoming involved with one, I have to say what an enjoyable read you two have produced.

This morning, I burst out laughing at Dave’s comment re: Your lathe was designed in the days when common sense was common.

Thank you both for being so entertaining.

Sam

[David Clark 13Participant @davidclark13]

Hi there

Regarding the bar feed, the compressor was rubbish.

We conected to a proper compressor via a regulator.

regards David

[websnailParticipant @websnail]

Sam. Thanks, Just trying to help from a distance. The trouble is, what I could show Andy in five minutes, takes me half an hour to type.

David Clark 1. Keeping the leather washers in good condition helps alot. Our compressors were ok. On one we had a little trouble but that problem was a kinked and collapsed rubber pipe on the far end of the barfeed. I found that sometimes when a heavy bar needed 'help' on first load, a quick puff from an airline 'up the pipe' from the rubber pipe helped spread the washer. Of course, it all depends if you are pushing a full lenght of bar, the shape of the bar section and even if you are feeding out at full revs or at a dead stop.

It sounds like you had problems but I found them not too bad, considering they had work with heavy steel bars, right down to light plastic.

[Anonymous]

Sam: I'm glad you've found the thread entertaining, although I wouldn't claim any of the glory. I'm just the novice here. I have wondered if the forum might find this thread a bit esoteric, although it's fascinating and very informative for me.

The compressor is definitely working on my lathe, as I can feel gentle 'puffs' coming out of the hole for the bar feeder air supply. In due course I intend to try out the bar feeder. The manual talks about using end plates and cotton thread for set up. Presumably this is just a couple of round plates with central holes that are used to stretch the thread through the bar feeder. The thread can then be ''eyed up' where it exits the bar feeder and enters the headstock, to see that it is central. Even I wouldn't contemplate permanently fitting the bar feeder outer support in my hall. Doooh, it's that H&S again, I don't really want to go A over T tripping over the bar feeder support! Instead I plan to fit it just inside the hall door, where it will be in the corner near the hinges, and therefore not in the way. I'll probably need a temporary outer support in the hall, or have to add a bit of weight to the bar feeder near the headstock. I see that Dave says that you can use the bar feeder with the spindle running. I hadn't thought of that, but it makes sense for saving time in production. I guess it could get exciting feeding a 1-1/4" bar on a reasonable speed range. I guess that's why the manual strongly recommends you have a blanking stop in the tailstock slots if they're not being used for tooling.

The coolant spray bar on my lathe can be adjusted for length, but the minimum is about 2", so I take Dave's point about using tape to block it off where required. I've got plenty of experience of spreading coolant around the workshop with my CNC mill; I don't really want to build on that experience. Talking of the dog clutch on the coolant pump, how do you move it? I checked the clutch to see if it was engaged when I was getting the coolant going. It was engaged, but it didn't seem all that easy to move, and I didn't manage it. Is there a detent or similar that needs to be operated before the sleeve can move?

It sounds like the speed change is a bit of a rigmarole. However, I will give it a go in due course, as it will be interesting to try the lathe across it's speed range. I have a set of spare belts, although whether they are a matched set is another matter. A couple of the belts have treasury tags with part numbers that agree with the Britan manual, but one of the B numbers doesn't agree. The manual says B30, the belt says B31. However, the belts on the lathe look fine, and I suspect that with the use I'll be giving them they'll last for ever.

I agree entirely with Dave on H&S. My comments were a gentle ribbing at those on another thread, where the OP had asked for a few ideas outside of model engineering, who jumped in warning of H&S Armageddon. While my workshop and machines do not meet modern H&S standards in terms of electrical cutouts and guarding, I do take H&S seriously. I have a fire extinguisher, first aid kit and eye wash in the workshop, and I always wear goggles when machining. As Dave says, it's all down to common sense and personal responsibility.

Regards,

Andrew

Edited By Andrew Johnston on 05/11/2012 11:24:08

[websnailParticipant @websnail]

Hi Andy,

Re: Bar feed. Gentle 'puff's are all you need. The 1 1/4" barfeeds always seemed to work better due to their greater surface area. Cotton thread works well and you have got the idea. The end support has a vertical adjustment, so you could screw it down to a square of timber, which could be held down a few ways. Hang a bright coloured towel on it to stop you going A over T or even worse, your other half.

When you operate the barfeed depends on the bar. Even things like, if it's a little bent or if it's resonating, which it will do and this will change, as the bar gets smaller in lenght and the resonating happens at differing spindle speeds. Experience will let you undo the collet, feed out some bar, catch the bar in the collet, bring up the stop from the tail stock,touch the end of the bar, open the collet, push the bar back against the air pressure and close the collet, all in a couple of seconds or so, if all goes well.

Re: dog clutch. It has a grub screw in the side. Undo and silde it back.

Re: Belts. I can't remember the belt numbers but I seem to remember that two belts are very close in size. I agree, yours will last forever.

Re: H&S. God knows what they would think of my old atlas lathe. No belt covers at all and I am fully comfortable using it. I do not however, take chances.

I would not adjust a circular saw, with it pluged in but I spent years with my hands very close to spinning milling cutters and splindles.

[Anonymous]

Hi Dave,

Thanks for the information. In due course I'll have a play with the dog clutch, just to see that it works. I've just discovered the first boo-boo due to the position of the lathe. I can't get the second shaft out of the tailstock because it clashes with the flypress on the right. If I cant the lathe round further to clear it I won't be able to use the bar feeder. At the moment my preferred option is to put the lathe on some standoffs, to raise it an inch or so. But I'll think about it before going to the trouble of making some. I'm not married, so I only have to worry about me going A over T over the bar feeder support; if I was married I doubt I'd be buying and playing with repetition lathes.

Right, now onto threading, here's a picture of all the threading equipment I got with the lathe:

Starting at the top are 1/2" and 8mm Coventry dieheads. I'm familiar with Coventry dieheads, and use them with the capstan unit on my conventional lathe. Presumably on the Britan these use the second shaft on the tailstock and utilise a stop, as shown on the lower shaft, to prevent rotation. My main question is about feeds, presumably the dieheads are used at low spindle speed and fed by hand until the dies bite. After that I assume that stops are set to allow the diehead to pull off and release the dies as normal?

The lower shaft I assume is also used in the second slot on the tailstock? At the moment it is set up with a self releasing holder for taps. Most of the small 'collets' below the shaft appear to be home made and are presumably for holding different sized taps? Again, I assume that the feed is by hand, until the unit reaches a stop and releases the tap. Next to the collets is what I take to be an adaptor for holding split circular dies. Does this screw onto the adaptor above in place of the tap holder?

At the bottom of the picture is what I assume is a self releasing tap holder for use in the tailstock tool turret? The tap in the holder is held in a split brass collet. I don't have any others of these in the bits and pieces, so presumably it is just a case of making one's own to suit as required?

Regards,

Andrew

[websnailParticipant @websnail]

Hi Andy.

Re: lathe height. If you are not bolting the lathe down, just stick some timber under it.

Re: Coventry dieheads. You are correct in how to use them. Put the lathe straight into reverse and slow at the same time. Run up the thread. Put the lathe back to forward and fast in one hit. Job done. Set the stop 'short' at first and work your way up to any shoulder. Quicker than re grinding the die sets. Remember, if you scrap a part due to thread not quite set properly, unlike a centre lathe, the next part can be made in seconds.

The lower shaft does indeed go in the second tailstock position. You are correct again. We almost never used these, as we perfered to use a dedicated tapping head in a drill press.

Re: Split dies. You have got 3 die holders but the body it screws onto is missing. Have another look in your pile of spares. The tap holder does go in the tailstock turret. There was also a die holder that fits in there. Both the die and tap holders have one way dog clutches.

Yes, you make up your own.

Dave

[Anonymous]

Hi Dave,

Is the body for the split die holders the right most part, under the lower shaft and to the right of the three split die holders? One of the split die holders was screwed onto it, but I took it apart for the purposes of the picture.

Regards,

Andrew

[Anonymous]

Dave: Doooh, why didn't I think of that; I've got loads of timber down the side of the house that'll do fine for raising the lathe.

I'm not sure I follow the instructions for the Coventry dieheads. Does the lathe run in reverse, or forward, when the thread is actually being cut?

At some point I'm going to have to get a grip and actually set up and make something on the lathe!

Regards,

Andrew

Edited By Andrew Johnston on 07/11/2012 12:12:42

[websnailParticipant @websnail]

Hi Andy, I found a way to blow up your picture.

Re: die holder. The die holder does indeed screw onto the adapter, which in turn screws on the shaft after the tap holder has been unscrewed. There are at least two sizes (lenghts) of the adapter.

There were/are, both left and right hand slip dog clutches (interchangeable) for left and right hand threads. All our smaller ex threads were done using the turret die holder, it's faster. As I said earlier, almost all our tapping was done off the machine.

Re: Covenrty die heads. Direction depends upon if left or right handed thread being cut. With a standard right handed thread, you cut the thread in reverse. ie, the SAME direction you use on a centre lathe.

Remember, the lathe runs in the OPPOSITE direction to a centre lathe in normal use.

Cheers

Dave

[Anonymous]

Hi Dave,

Ah, now I understand the operation of the Coventry dieheads! Presumably the threading/tapping heads work in the same way. For right hand threads, run the Britan in reverse until the stop is reached and the dog clutch disengages, then put the lathe in forward and back out the die/tap? I'm pretty sure that the threading/tapping accessories I have are for right hand; seems logical as I guess that they are the most common. I appreciate that you tended not to use the tapping attachments, but what sort of taps might have been used; hand, spiral point, spiral flute?

Right, next question, if you don't mind! Here's what I assume are the backstop parts, for second operations:

I wondered what the two lower items were when I collected everything; presumably they're extra backstops, of different lengths? I think I understand the principle of the backstop, but I'm not sure how it is fitted. On the top shaft presumably the collar on the left screws onto the headstock spindle on the left hand end? At the moment there seems to be a plain collar at that end on the spindle, although it does have a couple of holes for a pin wrench.

I'm keeping an eye out for Britan tooling, although I think it's probably a forlorn hope, as what tooling is likely to be around will probably be associated with a lathe; or nobody will have clue what it is!

Regards,

Andrew

[Anonymous]

The manual I have doesn't state that there are left and right hand versions of the threading/tapping attachments. So, out of curiosity, I've taken the tailstock capstan tapping head apart:

I'm impressed, a really simple design that presumably works well and reliably. I have a supplementary question. If I made a couple of dogs, one for the fixed part and one for moving part, with the opposite taper to that in the picture then presumably the head would operate with left hand taps?

Regards,

Andrew

Edited By Andrew Johnston on 08/11/2012 15:34:07

[websnailParticipant @websnail]

Hi Andy

Re: Die heads. Spot on.

Re: Taps. All were hand taps with spiral flute. Spiral point taps throw the swarf forward and in this case straight into a blind hole……….broken tap. Yet another reason for tapping off the machine.

Re: Back stops. There are two ways we used backstops. You have got the 'pucka' stops and you're right in how they work. We found them far too limiting, so we made up a bung, which was a good sliding fit for the spindle bore and had a shoulder. It also had a 3/8" bore and a threaded hole at right angles for a cap head screw. Method of use, tap the bung into the spindle bore, take up the little play with a match box lid size of paper. It won't need much tapping but tap it up to the shoulder. We had a selection of 3/8" steel bars, all of which had various turned ends. Pick the one you want, through the bung and nip it in place.

The second method. Make up a bung to be a free fit inside the collets around 1 1/2" long. Stick a M10 tapped hole in it. A turned and faced 6" lenght of studding and a M10 nut completes the back stop.

Re: Slip dogs. Spot on. The two dogs are the only difference between left and right hand.

Dave

[Anonymous]

Hi Dave,

Using spiral flute taps makes sense. I've got a pretty good range of metric spiral flute taps, and a few imperial ones, so shouldn't be a problem. However, I suspect that trying to find ME taps in spiral flute form might be a bit tricky! I can't see a need for left hand threads at the moment, but it is good to know that it's a relatively simple modification, should I need to do so in the future.

I expect that I'll need to get to grips with back stops fairly quickly, as one of the first things I'm planning to make on the Britan are all the studs I need for the cylinders on my traction engines, all 1/4" and 5/16" BSF.

Now onto knurling; here's the knurling tool and a few spare knurls:

It's unfortunate that a couple of the knurls seem to be singles, but that's life. At least knurling wheels are readily available. It seems clear how the knurling tool works, in principle at least. The two screws and nuts at the sides of the tool are used to swing, and set, the diameter of the work for the knurling wheels. However, any practical hints on how to knurl will be most welcome. Presumably the knurl wheels are set to form the knurl in one pass? I assume that some experimentation is required?

Regards,

Andrew

Edited By Andrew Johnston on 10/11/2012 11:31:57

[KWILParticipant @kwil]

Andrew, I cannot see that the knurling will be any different from when using a calliper type knurl holder on a normal lathe. With the calliper however the knurls move inwards evenly and the whole thing will "float" about centre. However with your device as each knurl apparently is individually adjustable by the screw and nut system and the holder is fixed on the centre line, you will need to take care to ensure equal engagement. Apart from that it should be quite straightforward.

[Anonymous]

KWIL: Yes, but! I'm not sure I've ever used a caliper knurling tool; if I have it would have been at RAE Farnborough back in the 1970s. Hence the question.

Regards,

Andrew – hot 'n' bothered, having spent all afternoon trying to weld the rolled rims for my traction engine wheels, give me some nice machining any day of the week.

[websnailParticipant @websnail]

Hi Andy.

Choose your knurls. Mount in the holder. Turn, face, undercut etc as the job requires.

Set the wheels just shy on diameter. Set the length on the tailstock stop.

Kiss the knurl wheels on the dia, then move both screws the same amount to balance the load.

We would knurl in forward slow (just move the long front lever to the right) touch the stop and just pull it back off again, then move the lever to the left for fast.Do not reverse spindle.  Always with suds. Depending what material your knurling, some 'welly' is required. They is/was a black handle/knob that fits on the end of the shaft to help. We never used feed, to knurl.

Dave

Edited By websnail on 10/11/2012 23:17:02

[Anonymous]

Hi Dave,

Thanks for the information on knurling. Is this the black knob you mean?

I've got one of them, although presumably it can be moved between shafts, or I could make some more.

Regards,

Andrew

[websnailParticipant @websnail]

Hi Andy,

That's the knob. Yes, it fits any shaft.

The shaft in the photo has the WRONG stop on it. You NEED one, with a built in mini shaft, which goes into the smaller hole between the two shafts shown. If you don't use the right stop, it will just spin at spindle speed as soon as any tool touches the work peice, taking your hand with it.

You are also missing the shaft lock, that lives in the other hole you can see.

Dave

[Anonymous]

Hi Dave,

Thanks for the tip on the stop with a secondary shaft; fortunately I do have one. I had noticed the missing shaft lock. For some reason it is sitting in the wooden collet rack along with the tailstock capstan collets. I do not know why it was removed, unless it had a reputation for getting in the way if it wasn't being used, or had a tendency to fall out if a shaft wasn't fitted? Which of course raises the question, when was it used? Presumably it locks the second shaft, the one with the black knob? The only time I can think it would be used is if the shaft contained a centre for supporting long work?

Regards,

Andrew

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