Taper attachment capabilities ?

I'm thinking about making a taper turning attachment for my Compact 5 - how acute an angle can you achieve with these things ?
The reason I ask is that I don't have a topslide and I'm wondering if it could do a similar job. 45 degrees would be enough, but I keep imagining the angles in my head and wondering if it wouldn't simply lock up.

I know I'll have to build a topslide anyway, to put the cut on, but it could be a whole lot simpler if it didn't have to swivel as well.

Hi Siddley

I think 45 deg will be way outside what you'll be able to achieve.

You probably need to start by looking at it a different way - how much room have you got at the back of the lathe to accommodate the taper attachment - that will determine what sort of angle you'll be able to swing the adjustable arm through. Also the further the attachment is from the back of the lathe bed, the more difficult it will be to keep rigidity and accuracy.

The other problem is that the steeper the angle you're trying to get the more friction will come into play on the head that moves on the adjustable slide. You won't want to slacken the cross-slide gib to allow for that as again accuracy could be compromised, but too tight and you won't be able to move it smoothly either - if at all at steep angles.

My guess would be that +/-5 deg should be happily acheivable, +/-10 deg might be and after that - who knows?

Keith

- who would appreciate some advice form someone whos "been there - done it", or used a taper attachment, as I need to make one for my lathe as well!

Just had another thought that might help - Nobby put up details of a "profile cutting" system that he'd made for his machine - you might adapt that to use  with the cross slide to get the 45 deg angle.

Edited By Keith Long on 12/12/2012 19:25:24

Thanks Keith, that's pretty helpful. I don't want to be a pain but could you link to the thread for me ? I can't seem to find it.

Hi Siddley

I can't find the thread but if you go to the photo albums and look for those by "Nobby" you'll see one called "copy attachment". There are about 6 or 8 photos there of his device. To get more info best talk to Nobby direct I suggest either a general call in this thread or send him a personal message.

I think the device was covered in a thread about general workshop tooling or techniques but needles and haystacks come to mind!

Keith

Ta Keith - I've fired off a PM to Nobby. Having viewed his album I now have to make one of those clever multi position carriage stops as well

Hi Siddley & Keith
Its "Nobby " here . The attatchment i made was mainly for using a template to turn machine handles etc. I think 45 degree's would be pishing it a bit as Keith said .
Thank you Keith for remembering my post on this There's another system I use may be better and quicker to make . One you could use and set up with a Sine bar using a dti.I will have a look and post photo on this thread
Nobby

Edited By Nobby on 12/12/2012 22:59:41

Hi Again Guys
You could use a straight template Up to what angle ? I will have a look The Radius on the tool would have to be the same as the clock to be accurate
Nobby

Hi Nobby, thanks for replying. I mentioned 45 degrees but that was really off the top off my head - 30 degrees would get me by - although it's not ideal.

I never realised how much I used a topslide until I didn't have one. I'm not even sure I'm barking up the correct tree here. It's not that I'm scared of making a topslide, I actually enjoy improving machine tools and making accessories - it's just that the centre height on the Emco is such that I don't have much space to play with in order to make one that isn't compromised in some way. Plus I have a requirement to cut morse tapers 1 through 3.

HI Siddley
On my Vintage Drummond & Exe lathe there was no topslide so I made a small low one with about 4" of movement And found it great for screwcuuting and for turning 30 degree centers ect
I enjoy improoving small machines as my S7 Mk one needed a tailstock .handles, motor bracket etc
Nobby

S

I would think that a taper turning device wouldd be deployed for shallow tapers (Morse etc), a top slide at an angle for what is essentially bevelling - 45 deg 30 deg etc.

The topslide on the Compact 5 has only a short traverse, there comes a point where insuffient dovetail is in contact to give rigididty, hence only short tapers possible. The other problem is of course setting to the required angle. A simple cross slide used as a feed device for the cutting tool while the taper is put on by the taper set on the device is needed

Designing a full blown taper turning device for the Compact 5 has also got to cope with the inflexibilty of not having a disconnectable half nut on te lead screw.

John

Great stuff Nobby, there are enough ideas there for a couple of years work

A simple cross slide used as a feed device for the cutting tool while the taper is put on by the taper set on the device is needed

My thoughts exactly John. I was wondering about the simple cross slide also incorporating a retracting tool holder.
I have got to do something about the lead screw situation as well.

Maybe Santa will bring me a brand new Hardinge HLV ? I've been good this year...

Hi Siddley

"Maybe Santa will bring me a brand new Hardinge HLV ? I've been good this year..."

No your in Spain - have to be the Three Kings!

Keith

Hi Guys

"A simple cross slide used as a feed device for the cutting tool while the taper is put on by the taper set on the device is needed"

Maybe I'm misreading this but, on the Myford taper turning attachment at least, the feedscrew for the cross slide is disconnected and the cross slide is controlled by the taper turning attachment set to the appropriate taper angle. The tool IN FEED is put on by the topslide for each successive pass along the taper.

Regards

Norman

If there are 3 of them they can help me install it then - Baltazar looks pretty muscular

Gentlemen,

I made a full length taper turning attachment for my Myford S7 variant using a 20 inch length of 18mm hydraulic ram as a guide. It is hard chrome plated, straight as a die and resistant to bending as well as being on size to within a gnat's whatsit. The bar is carried on two cantilever supports built out from the two ends of the bed; the tailstock end has both fine and coarse adjustments to set the angles. The headstock end is just in steps of 50mm, so by juggling about you can cater for tapers that close up or open out with tool travel towards the headstock. Setting in my case uses the DRO to define the angle over a set length.

The slider is a hefty section of aluminium bar bored out to be with a close fit on the guide bar and is closed at the two ends with felt wipers to keep the grot out. The vertical link up to the cross-slide is a sturdy 40mm diameter chunk of bar to resist any side motion flexing.

In use you disconnect the cross-slide feed screw and let all the motion come from the guide bar. Angles of +/- 10 degrees are about all you can expect before it gets cranky and moves in jerks.Tool feed is put on by the topslide. My installation is permanent, it is far too fiddly to be putting it on and taking it off and I've cut good Morse tapers with it.

In my opinion it has the advantage of quick access and the ability to cut a really long taper that the proper Myford accessory can't do, being limited in length. That is a brief description, I have no drawings since it evolved as it grew, but it should be enough to impart the essential elements..

The vital guide material can be bought as a cut length from hydraulic engineers who offer a repair and overhaul service. I think mine was about £1 an inch at the time [~7years ago] Look them up in Yellow pages.

Brian

Edited By Brian Wood on 13/12/2012 18:25:53

That's really interesting Brian, thanks for taking the time to reply ( must have taken you ages to write all that ! )

One thing I have got is plenty of silver steel ( my father in law worked for Cromwell Tools and passed his staff discount onto me, so I used to buy loads of the stuff and keep it for a rainy day ) That will make a nice guide rod for a taper attachment. I think I've got some 20mm and I know I have a 20mm reamer.

I also scavenge broken printers ( last one cost me a euro ) for the guide rods that they use. The rods are quite accurate in dimension and sometimes come with a couple of nicely fitting sintered bronze bearings that the print head carriage slides on. They aren't thick enough for this job, but they are handy things to have around - they machine nicely too.

Nobby - your idea for the copy attachment was too good and useful to forget - filed away for future reference.

Thanks from me as well Brian, sounds as though the unit you built is very much along the lines that I was planning. I've got some old car suspension struts with 17mm dia rods that will do nicely for the guide rail.

Keith

Brian,

Any chance of posting a picture or two?? I always think a photo tends to be better than words. It sounds just the kind of thing I`ve been thinking about for sometime.

Regards Alan

Edited By Flying Fifer on 13/12/2012 22:49:29

You mean something like this? Silver Steel guide bar with PB lined slider connected to the cross slide.