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Bob
Serious Geek!

United Kingdom
1263 Posts

Posted - 07 Mar 2004 :  08:37:00  Show Profile  Reply with Quote
quote:
Originally posted by peter fogwill



It is not a very good picture I will see if I can get a better one.

The thing I want too make is at the top left of the picture, the outside diameter is 30mm, it has a screw thread inside the hole about half way up. The outside has a diameter of 30mm gradually coming down to about 20mm

The dimensions are quite critical as the part has to fit neatly in another part.

The machine I mentioned is no good for what I need, I went to the shop today and measured the bar capacity and it was 28mm I need 30mm, so back to the drawing board. I also asked about the mill and he said that it was fine for facing a surface, but not too hot at anything else.

Peter



I don't think the machine you had in mind could do the taper turning.

Bob
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peter fogwill
New Member

21 Posts

Posted - 08 Mar 2004 :  00:24:16  Show Profile  Reply with Quote
quote:
Originally posted by Fluba

whats the piece for btw? i'm intreagued(sp) ;)



It fits on to a telescopic pole, then a couple of gooseneck fittings then a brush. It is for cleaning windows, I sell window cleaning systems.


Peter
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peter fogwill
New Member

21 Posts

Posted - 08 Mar 2004 :  00:28:50  Show Profile  Reply with Quote
quote:
Originally posted by Bob

[quote]Originally posted by peter fogwill

I don't think the machine you had in mind could do the taper turning.

Bob



Do you know any that will? I had asked about the taper and the guy in the shop said it could be done by hand rather than automatic, could it be?

Peter
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peter fogwill
New Member

21 Posts

Posted - 08 Mar 2004 :  00:30:32  Show Profile  Reply with Quote
quote:
Originally posted by Bob

[quote]Originally posted by peter fogwill



So you can see the hole through the mandrel is only limiting long workpieces or bar stock operations. Looking at the number/ and size of your pieces you could probably use the chuck to hold the work, none of the work actually protruding back from the chuck into the mandrel.

Hope this makes things clear.

Bob



Yes I understand now, thanks.

Peter
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Bob
Serious Geek!

United Kingdom
1263 Posts

Posted - 08 Mar 2004 :  09:52:17  Show Profile  Reply with Quote

Hi Peter

I am still rather in the dark about the actual size of the component. From what I can deduce it looks to be about 400 mm long with a large diameter of 30 mm tapering to 20 mm at the narrow end. There apears to be a flat with a drilled and tapped cross hole at one end.

If that is the case your best option for creating the taper is to offset the tail stock and turn the piece between centres. Another option might be to use the compound slide to turn the taper, but I doubt your lathe will have sufficient travel on the compound slide to do this and it is very tricky to pick up the taper without leaving an obvious mark if you try moving the saddle and then completing the taper. A further alternative is to use a taper turning attachment that would be ideal for this type of job.

The flat is a milling job, but don't dispair, you can do it in the lathe! I would put an end mill in the mandrel, preferably in a proper milling collet, but you could get away with gripping it in the chuck and making a little jig to fix the work vertically to the crossslide. (much easier if you have a T -slotted cross slide) you could mill the flat and drill the cross hole from this fixture.

With the anticipated production run of 150 it would be worth the time making the jigs to carry out this work. I would try to do all the milling first and then taper turn the whole batch rather than doing the whole job in small batches.

Else you cold find someone with spare CNC capacity and get them to do the work. I would say that eight squids sound a reasonable price for the work.

Bob


Edited by - Bob on 08 Mar 2004 09:54:13
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peter fogwill
New Member

21 Posts

Posted - 08 Mar 2004 :  22:23:16  Show Profile  Reply with Quote
Thanks again Bob. No there is no flat where the hole is just the hole.

It seems then the biggest problem I would have is the taper.

I am afraid all this

"offset the tail stock and turn the piece between centres. Another option might be to use the compound slide to turn the taper, but I doubt your lathe will have sufficient travel on the compound slide to do this and it is very tricky to pick up the taper without leaving an obvious mark if you try moving the saddle and then completing the taper. A further alternative is to use a taper turning attachment that would be ideal for this type of job"

is away above my head, if so am I wasting my time trying to do them myself? It was not so much the money, I enjoy tinkering about with things, and have wanted a lathe for years. I do a bit of inventing, and a lathe would be very handy for me if I got the hang of it.

Peter
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JamesC
Geek!

United Kingdom
398 Posts

Posted - 08 Mar 2004 :  22:54:07  Show Profile  Reply with Quote
Peter

I would go back to my earlier advice, go along to an evening class. If it's anything like the one I'm currently attending ther will be a large range of machines and a good few people on hand to help with hands on advice.

Once you've managed to make a few you should have a much better idea of how to proceed and what size of machine you will require.

What area are you in, if you are anywhere near Southampton I can recomend Eastleigh College.

Regards

James
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peter fogwill
New Member

21 Posts

Posted - 08 Mar 2004 :  23:03:46  Show Profile  Reply with Quote
Hi James, I am in Scotland. I will have a look tomorrow and see what courses are on the go. Could you tell me a little bit about your course, how long it last? how many nights a week? how much it costs?

Thanks,

Peter
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Bob
Serious Geek!

United Kingdom
1263 Posts

Posted - 08 Mar 2004 :  23:17:27  Show Profile  Reply with Quote
Hi Peter

Don't be put off taper turning between centres, it just needs a bit of setting up. Once the tailstock has beem moved across by half the difference in diameters from end to end (30mm - 20mm =10 mm, 10/2 =5mm offset) all you need to do is drill centre holes in each end of the workpiece, put some grease on the end of the fixed centre and then turn the work normally.

I would suggest getting hold of a copy of Workholding in the Lathe by Tubal Cain (Argus Books workshop Practice Series No 15) This will make it very clear how to go about the job. Don't forget to put the tailstock back to spot on centre before you use it for drilling again or you will smash your centre drill every time.

Bob

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peter fogwill
New Member

21 Posts

Posted - 09 Mar 2004 :  22:25:36  Show Profile  Reply with Quote
Thanks Bob I found the book at http://www.lathes.co.uk/books.htm
I have seen quite a lot of lathe books, any other you would recommend?

Peter

Edited by - peter fogwill on 09 Mar 2004 22:41:06
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JamesC
Geek!

United Kingdom
398 Posts

Posted - 10 Mar 2004 :  00:22:31  Show Profile  Reply with Quote
niversity) about the Highland development trust or something similar where engineering shops were set up with a wide array of machinery available to educational bodies and for a small fee to the public and businesses. They even had full CAD/CAM manufacturing facilities and rapid prototyping via one of the Univerities. I may be worth your while investigating if this is still in operation as it could solve all your problems.

Regards

James
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peter fogwill
New Member

21 Posts

Posted - 14 Mar 2004 :  23:30:43  Show Profile  Reply with Quote
Hi again guys, thanks for all the help in the past, and now that I know a little more about lathes I am glad I didn't go for the Clarke one. I do quite fancy the Myford 7 or Super 7, nearly everyone I have spoke to about lathes end up recommending them. However they are hard to come by unless you want to spend over 1000, and I don't.
I have also been told that the Boxford is very good, but as they are usually ex schools or college, they are normally 3 phase, and I need single.

I have been looking at a lot of local adds and have found a "Drummond A Type 4" Round Bed" The guy selling it is busy and I won't get a chance to see it until Tuesday or Wednesday so thought I would ask the opinions on here first, anyone know anything about them? are they any good? I know it is very old but seemingly it has been stripped and blasted, and modernised a bit, it also comes on a stand and has a few extras, the cost is 250. Anyone?

Peter
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Bob
Serious Geek!

United Kingdom
1263 Posts

Posted - 15 Mar 2004 :  08:42:12  Show Profile  Reply with Quote
quote:
Originally posted by peter fogwill

Hi again guys, thanks for all the help in the past, and now that I know a little more about lathes I am glad I didn't go for the Clarke one. I do quite fancy the Myford 7 or Super 7, nearly everyone I have spoke to about lathes end up recommending them. However they are hard to come by unless you want to spend over 1000, and I don't.
I have also been told that the Boxford is very good, but as they are usually ex schools or college, they are normally 3 phase, and I need single.

I have been looking at a lot of local adds and have found a "Drummond A Type 4" Round Bed" The guy selling it is busy and I won't get a chance to see it until Tuesday or Wednesday so thought I would ask the opinions on here first, anyone know anything about them? are they any good? I know it is very old but seemingly it has been stripped and blasted, and modernised a bit, it also comes on a stand and has a few extras, the cost is 250. Anyone?

Peter



The Round Bed Drummond is a famous lathe, but very old now. Age in itself is not too serious, but mis-use and cosmetic restoration can be a problem in a machine of this age. Try all the normal tests you would on any machine.

Check the saddle moves equally freely from end to end of the bed. Watch out for slackness near the headstock as this is where it will have been most of its working life.

Put centres in the headstock and tailstock and bring the points together. Chech they meet. (Useful tip, try to trap a 6 inch steel rule between the centres. If there is any mis-alignment the ruler will not lie perpendicular to the axis of the lathe. You can use this to reset the tail stock centre after taper turing)

Put a block of wood between the chuck and the lathe bed and try to lever the chuck up, feel for any movement, there should be none.

Look for wear around the tailstock mandrel, this can be difficult to sortout.

Move all the slides throuhout their full range. Watch for slack and tight spots. All equally slack is OK as this can be adjusted by tightening the gibs.

Run the lathe and listen to the gears, there will be some noise, but not too much.

If it has a geared headstock, check all the teeth are present on the bull gear. (This is a common fault on Myfords, especialy ex-school machines where students attempt to engage the back gear while the lathe is running.)

Look at the lead screw. Compare the end near the headstock with the other end. It should have a square thread, but on an old lathe this may be worn into an almost round thread profile.

Inspect the Morse tapers in the headstock and tail stock, Look for rings scored on the inside where the tapers have slipped during heavy abuse.

look at the lathe bed near the headstock. look for markes where the chuck jaws have hit the bed or worse evidence of hack saw cuts where the user has been sawing off work in the chuck without the chuck board in place.

Look at the motor, does it look electrically safe? Has it got VIR cable, if so it may need replacement.

Try to find out what tooling comes with the lathe.

Normal tooling would be:

Face plate

Catch plate

Tailstock centres (1 hard, 1 soft, possibly half centre)

Three jaw SC chuck

Four jaw independent chuck

Full set of change wheels

Oil gun/grease gun

Tool post

Tail stock chuck

Dust cover (I am a perfectionist!)

You should expect some guards over the change wheels and belts.

(Not all ex-school Boxford are three phase and it is quite straight forward to fit a single phase motor to an CUD Boxford)

Bob

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peter fogwill
New Member

21 Posts

Posted - 16 Mar 2004 :  00:15:12  Show Profile  Reply with Quote
Thanks again Bob, like I said I may be going to see it tomorrow, I will only buy it if I am really impressed with it, I will let you know how I get on if I go.

I know what you mean about the Boxford being able to change to a single phase motor, I have also been told you can get an adaptor of some sort to change the 3 phase to single.

The more I read about the Myfords the more I am impressed with them, especially the Super 7 with the powered cross feed, which would be particularly handy for my tapered jobs. they are expensive though I have tried Ebay but you would be very lucky to get one under 800.

Peter
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Bob
Serious Geek!

United Kingdom
1263 Posts

Posted - 16 Mar 2004 :  09:50:56  Show Profile  Reply with Quote
quote:
Originally posted by peter fogwill

Thanks again Bob, like I said I may be going to see it tomorrow, I will only buy it if I am really impressed with it, I will let you know how I get on if I go.

I know what you mean about the Boxford being able to change to a single phase motor, I have also been told you can get an adaptor of some sort to change the 3 phase to single.



Avoid single phase to 3 phase converters at all costs, most of them are useless. They produce the correct waveform, but not the correct peak to peak voltage so the motors lack power.

quote:


The more I read about the Myfords the more I am impressed with them, especially the Super 7 with the powered cross feed, which would be particularly handy for my tapered jobs. they are expensive though I have tried Ebay but you would be very lucky to get one under 800.





The power cross feed will be useful for facing, but i don't think it will help your taper turning, anyway only the very top of the range Myfords had power crossfeeds so I would not get my hopes up on finding a cheap second hand machine with power crossfeed (There have been lots of plans published for modifying ML7s to have power crossfeed, but check the workm,anship of any modification.

The thing you really need is the taper turning attachment.




Isn't this a beautiful lathe!

This is a job rather like your taper. The work is held in the three jaw SC chuck and supported by a running centre in the tailstock. There is a fixed steady supporting the centre of the work. The taper turning attchment is being used to produce the shallow taper on the work.

Have a look at this site for full details of the setup.

http://easyweb.easynet.co.uk/~chrish/tturning.htm

Bob

Edited by - Bob on 16 Mar 2004 09:53:39
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