I must say that given the difficulty of making this, which would seem to need a way to hold a dividing head at a 45* angle, I think the design is not very well though out. I'd be inclined to machine the arc vertically on the end of the bar and put the scale on the top surface with a small block for the fiducial mark.

But actually, is the scale likely to be very useful?  You could always use a protractor to set the angle.

Edited By John Haine on 07/11/2022 11:30:26

I'm with John Haine and MichaelG on this, but if you are determined to follow the original design, as a temporary measure, you could print the lines on clear decal printing paper sheet and cut it out to apply it to the surface. I did this when I made my simple indexer, for the 10° marks on the "vernier" wheel. Here's how it turned out:

The lines were put on with an engraving tool in the mill – it's the numbers that are printed. In you case it would involve a bit of jiggery-pokery in CAD to get the wrap-around shape, but it is doable.

John

Whilst I agree this is not the best of design from a manufacture point of view if the rotary table can be mounted vertically as some can or against an angle plate (as I do for similar instances) then it should be easy enough to do if the mounting of the RT can be swung across the table at the desired angle. A rotating single point cutter should do the job as long as everything is set on the RT centre line.

Tug

Using the tilted head would be another option – I don't have that luxury on my Linley. Were I to do it the RT would be mounted vertically and set to one axis of the mill at the required angle to match the angle on the part.

The workpiece – plate – is set horizontal on the C/L of the R/T with the radius and angle pre machined and set such that the radius matches the arc of rotation. The cutter is set dead on centre height and the grooving done as if cutting a gear by moving the relevant axis, depth of cut provided by the other axis. If the spindle can be locked (not usual I agree) then the cutter can just scribe the work.

Not an ideal set up I agree too but something that can be done.

Tug

PS just found this – similar to this set up for cutting bevel gears

Div Head set a an angle to axis as suggested – as you can see a sub plate was required in order to enable this to be achieved

Edited By Ramon Wilson on 07/11/2022 13:56:01

Edited By Ramon Wilson on 07/11/2022 13:59:01

Your picture shows the graduations on the surface of a cylinder. The ones he needs are on the surface of a cone. The printed paper will either wrinkle up at the top or rip apart at the bottom.

Precisely, Michael. I have vague memories of a function in one of my cad programs that will wrap text along a path (truncated cone), but at the time of my response couldn't recall it. As the OP has had ample solutions proposed, I didn't think that it was worth further investigation.

John

Like a dog with a bone, I'm back! I created a pattern of graduations on a 45° cone in Alibre Atom:

And there it stumped me. There is an add-on in Alibre Expert which will convert that 3D shape to sheet metal – i.e. "flatten it out" – but this is not available for Atom. I tried exporting it as a STEP file to Fusion 360, but – guess what? – you have to upgrade to get the sheet metal conversion function. So it can be done, but other, better, solutions have already been postulated. This was just an exercise for the grey matter from my point of view.

John

Edited By John Hinkley on 08/11/2022 10:44:47

Rather than set up on a rotary table to index the graduations, could you not instead rely on the taper turning attachment's own inbuilt micrometer adjustment screw? This will move the slide bar by very fine increments to whatever degree setting you desire. You would then only have to set the taper-turning attachment's base at a 45 degree angle on the mill table and clamp it down and then use an engraving cutter in the mill spindle to engrave the line. It could be set so the attachment is hanging half off the table, thus reducing head height to less than 5 inches or so.

Or even do a similar thing mounting the taper turning attachment at 45 degrees horizontally on the T slotted cross slide of a Myford lathe and hold your engraving cutter in the chuck, using the cross slide for length of cut and the saddle movement for depth of cut via leadscrew hand wheel. All the while using the attachment's own micrometer adjusting screw to vary the angle for each graduation.

Or you could even clamp the attachment to the bed of the lathe with suitable height packing, laid down horizontally, and use a simple lathe toolbit sharpened to a V and held in the toolpost to engrave the graduations by racking the carriage back and forth like a hand-shaper or planer. Depth of cut would be set by cross slide. Line length by carriage stop. Graduations by the attachments micrometer screw again.

Edited By Hopper on 08/11/2022 12:03:43

I must say I'm bemused by all this discussion of "how" while ignoring the question of "why". Even if you have a scale I think it's of doubtful value.

• The most common taper we cut is probably MT2 and an angle scale just isn't precise enough to do that, you have to use a DTI to get zero movement when winding the saddle backwards and forwards. Someone pointed out above that they keep their TTA set to MT2 anyway (or use a sine bar).
• OK, if you just want an approximate taper then a scale is useful for quick setting, but…
• …just how often do we cut long tapers anyway?
• It should be simple to arrange a gadget to allow a protractor to be used to set the angle against a test bar or similar when you do want to make a taper.
• If you make the scale on a piece of paper it will get soaked in coolant and probably peel off. You could make it on a bit of shim somehow, but then it needs to be fixed, and anyway if it's on a sloping face it's harder to read as I pointed out.

If you want a machining challenge by all means find a way to engrave the scale obliquely, but if you just want to make tapers don't bother in my view, or engrave it on the flat top face.

The scale on the Smart & Brown model A taper turning attachment which is pretty much identical to the one on the later 1024 lathes is not calibrated anywhere finely enough to produce Morse tapers, you just have to creep up on the exact fit. Even using a DTI exactly on the centreline is no guarantee of the perfect taper. A vernier scale giving a resolution of 1 minute of arc (1/60th of a degree) will only get you close, and only having the mating part will get you a perfect fit. That is what is so annoying about Morse tapers, you get one perfect, but every size is a different taper.

Removed

Edited By duncan webster on 08/11/2022 23:43:11