Taper Turning

[MattMaie]

I have a need to turn tapers for some tooling I need to make, but I haven't got the funds to buy a taper attachment for my lathe, nor do I really want to try those modifications some make with boring heads for offset turning. I want to be as exact as possible and for me, that means offsetting the tail stock.

What I am making is a tapered reamer for finishing the bore of a woodwind instrument. I plan to have a few extra inches on the shank to be gripped in a Jacobs or lathe chuck. How do I calculate how much I need to offset the tail stock? Do I need to take in to account the entire length of the work piece? Or do I only need to offset for the length of the tapered portion?

 

[Blogwitch]

You might do OK if you use your topslide (compound) to get the taper and to make your reamer like a D-bit.

John

 

[MattMaie]

Its a long and very slight taper, about 0.020 per inch. Compound wouldn't really be suited for that kind of job. The tapered portion needs to be around 14 3/8 long, erring on the side of making it slightly longer as well.

 

[Wizard69]

Its a long and very slight taper, about 0.020 per inch. Compound wouldn't really be suited for that kind of job. The tapered portion needs to be around 14 3/8 long, erring on the side of making it slightly longer as well.

That would be an offset of 0.3 inches if you had a 15" work piece. You would have to check to see if your tail stock can even be offset that much.

You didn't mention your lathe size but that is a factor When it comes to finding the best solution.

Doing a homemade taper attachment is a possibility though they can get to be expensive if you need outside help to do the long pieces. They would be long and robust to handle a 15" taper properly.

If you are hardly with electronics you could do a stepper drive on the cross slide and sync its operation with spindle rotation. This wouldn't be CNC as we know it today but rather a kludge to get the job done. A variant of the Electronic leadscrew project might be in order as the idea is similar.

Of course the more involved option is to CNC the lathe. Either of these electronic options is either easy or complex depending upon your electronics background. However these days they can actually be rather cheap compared to building a long slide taper attachment.

 

[goldstar31]

Taking a stab at the answer, I would suggest that the old way to do a chanter on 'half longs' and the Great Pipe is to use the well tried French 'Napoleonic. triangular bayonet.

However, this is a short bore and perhaps it is merely a descant recorder. They are two a penny and hardly worth the effort.

As far as getting a taper from the tailstock end, using a boring head is one of many solutions and is classed as a beginner's exercise.

If you have a Myford, you can knock up a welded bracket which will 'do' long tapers and only utilises a length of either PGMS rod or 'silver steel'

Again, accessing some firm like Windcraft in Cambridge, Cambridge or Ferees Tools in the US might be of use.

I doubt that I will not alone is asking for clarity


Norm

 

[MattMaie]

Uilleann pipes, border pipes, and highland pipes.

There are days I wish I had a Myford. They look like very solid machines that would suit my needs perfectly. Right tone I have a Grizzly G4002. 12 inch swing and 24 inches between centers. I really need to find a way to make what I have work for me. I can’t afford the investment into new machinery right now (or used, as it were). I also can’t really justify the expense of a taper cutting attachment right now either.

 

[fcheslop]

Would this idea be of any use
http://www.hemingwaykits.com/acatalog/Set_over_Centre.html

 

[pkastagehand]

Lots of websites and some Youtube videos. I've done this but don't remember the math but should be easily found.

Main things is doing it between centers and not trying to use the chuck (fairly obvious hopefully). Otherwise it is just geometry. Hardest part is measuring the offset accurately once you know what it needs to be.

Paul

 

[goldstar31]

Would this idea be of any use
http://www.hemingwaykits.com/acatalog/Set_over_Centre.html

Yes, I have an Arrand which is graduated to do 1, 2 and 3 Morse tapers but . whilst it is simple, making a boring head does a lot more useful things apart from boring. If you play your cards correctly, a boring head also does off sets of poppets but those intriguing beasties like ball handles.

I'm wondering what reaction there will be when the decision has to be made about either a cat's head chuck and a fixed steady of a square billet for the exciting prospects of poking a 19" hole of only 6 or 7mm diameter.

And the drill pops out- at the side.

 

[bazmak]

To do what you are looking for with the lathe you have i think you can offset the tailstock OK.You will need a centre and drive dog etc in the headstock
Offset is calculated by the taper dia over the centre distance of the workpiece
If you have 20 thou per inch over 15" then the offset is 0.3".First thing is to check for more than the total offset and mod the tailstock if requd.Adding push/pull screws to the tailstock will be a great help.Then its trial and error
Set approx and check etc.Over long and over dia will help.With the push /pull screws you can set a dial indicator to the tailstock for accurate offsetting but
it will take a few moves and trial and error.I would not consider it too difficult

 

[kwoodhands]

I believe you can find plans for an offset tail stock accessory at Projects In Metal website.
I made one for myself, not as fancy or convenient as the Hemingway product mentioned in another post. I have to fiddle a bit to get an exact offset, might add some type of screw adjustment in the future. The offset tailstock accessory works well. Make the point from tool steel. The first point I made was from L214 steel which looked nice but soon wore down. New point from drill rod is about 5 years old and never been re-honed.

mike

 

[goldstar31]

On the face of it, it all appears as a rather elegant solution but it is rather like fitting an ashtray onto a motor bike!

Once one makes the 'metal' cone, as it stands, it will not bore. It needs a cutter or cutters to open pre-drilled hole.

If one is making a set of say Highland pipes in metal( Oh Yes they are, more sets and pipers were lost on British tank turrets than can be believed today) but one makes a roughing and then a finishing reamer set. If one is tackling a wooden taper, it may be possible to 'get away' with a single tool with a minimum of three blades. Again, at a push it might be possible to remove all but say 20thous short of half the cone and go into D bit technology. However, somewhat Quixotically, one might learn how to make D bits to do the long parallel holes on the drones or guilles

Going back to Shakespeare and 'Aye, there's the rub, NONE of this is any use if one doesn't sort the harmonics out-- and clears his aching throat, drills the tone holes in the right places- and possibly under cut them.


All of this assumes that the maker has the ability to make both single and double reeds.

Oh if you think that that is all about it, one needs something called 'Perfect Pitch'

My late wife had it, so has my only daughter and one of my little

grand daughters.

How does one get Perfect Pitch? Now that isn't something which I possessed.

N

 

[john_reese]

If you are switching between cylindrical turning and taper turning an offset adapter for the tailstock would be an asset. You certainly don't want to go the test bar route every time you go back to cylindrical turning. As Goldstar31 suggested a boring head can substitute for an offset adapter.