Taper attachment

mickri

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Some of my upcoming projects will require me to turn a taper. So I have been looking into lathe taper attachments. Everyone that I found requires you to make a contraption that hangs off the back side of the lathe except for one which uses a wheel attached to the crossslide turned by a taunt wire. Don't know if it is kosher to include a link to another site so I copied the post that describes this taper attachment.

Here's a simple taper attachment that is easy to make. It uses a taut wire wrapped around a
specified wheel which is attached to the cross-slide lead screw. The wire is attached to the
lathe bed by means of two stand-offs. This, of course, works for inside, outside, long, or
short taper turning.

Plans for this taper attachment were published by the Home shop Machinist:

Title: An Accurate Taper Attachment for Under $5.00.
Author: J.O. Barbour, Jr.
Issue: March-April 1986 Page 20


How it works: A wheel is machined to an exact diameter needed for a certain taper. This
wheel is attached to the cross slide lead screw. Then a taut wire is wrapped once around
this wheel and fastened parallel to the lathe bed by stand-offs (see photo below).

When the carriage moves it will automatically turn the cross slide in proportion to the
machined wheel...thereby giving the correct taper. The wire doesn't have to be very strong
since most of the stresses are on the cross slide lead screw or carriage. The main thing is
that the wire wrapped around the wheel must not slip...which one wrap should accomplish when
wire is drawn taut.

I think this works great, especially for tapers that need to be made over and over again.
Set up time would only involve the time necessary to attach the wheel and pull the wire
taut.

All parts don't need to be made with any particular accuracy with the exception of the
wheel. This wheel needs to machined very accurately (minus one wire diameter less than
calculated diameter). This is very easily accomplished using the lathe and micrometer. Of
course, the stand-offs need to be strong - but that's not a problem!

Here's an example: Lets say a 1/8" taper per foot is desired and the wire being used is
0.020" music wire. Since the taper is being cut on both sides, the cross slide only needs go
1/16" per foot of carriage travel. If the lathe has a 10 TPI lead screw then the wheel needs
to turn 62.5 percent of a revolution in 12". This means that the circumference needs to be
0.625 X 12 = 7.500" then divide by pi to get a diameter of 2.387". So the final diameter of
the wheel will need to be 2.387 - 0.020 = 2.367".

As one can see, this is very handy as it doesn't depend on the length of material the taper
is to be cut on, as it would be on a tailstock offset, just the taper per foot.



One additional note:

For the wire "clamp" on the stand-offs (which is not part of the article) a small drill
chuck was used. This chuck sells for about $8.00 and can be obtained at most hardware
stores. The chuck comes threaded for a standard size and the bolt used is threaded for about
three inches. Flats were also machined on each side of the bolt so one can use a wrench to
hold the chuck from turning when tightening the wire. In addition, the bolt has a small hole
drilled thru its entire length for excess wire to pass. This setup works great to achieve
the proper tautness of the wire so it will not slip on the precision machined wheel.

Have any of you guys used this type of taper attachment? What do you think?
 
Personally, I would build up a conventional type taper attachment or use the tail stock offset method. If the wire taper method
was really great, you would see it on commercial machines.
 
My lathe has a taper attachment, but a lot of folks use the tailstock offset, or a boring head in the tailstock.
But let us know how that works out , with pics ,:grin:
 
I have tried to find pictures with no success so far. The pictures with the post that I copied were no longer visible. There was a thread about it on Practical Machinist. Their main concern was if it would be accurate enough to do morse tapers and the small size of the wheel to do tapers over 1/2" per foot. Again no photos. I'll try to contact the man who was using it to get some photos.
 
Here is one I made cutting a taper on my Logan. It swings on a base plate . After I have set it to a taper I drill thru the top and bottom plate and use an 1/8 pin so that
I can return to that taper later if I want to cut it again. For my Logan spindle taper I stamped a letter l Next to that hole. Next to a Morse taper I stamp a M1,M2 or whatever taper it is so that I can return to that taper by pinning with a 1/8 inch pin.
I built it to fit on my production cross slide but you could make it fit any cross slide.

https://photos.app.goo.gl/ObZJGeo67hyuSsbP2
 
I like your taper attachment but it would be too short for my projects. The taper on one project needs to be around 6" long and the other projects will require a taper length of around 21".
I have sent an email off the man who posted the wheel taper attachment I referenced above.
 
I think it's a great idea for those of us who turn tapers very occasionally on machines that never had a taper attachment offered
Mark
 
I agree Mark. The tapers that I want to turn just have to look nice. I am not trying to make a morse taper that has to be spot on with little room for error. Still waiting for a response to my email.
My first project is to do what is known as growlerizing the axle shafts on my 1966 Midget. Midget axles have a stress point where the outboard edge of the spider gear in the differential bears on the axle shaft. This stress point causes the axles shafts to snap at this point. Growlerizing the axle relieves the stress point. What you do is measure in 1 inch from the end of the axle and then turn the axle down to the depth of the splines for about 4 inches. You then taper the next 6 inches back to the original diameter. This is what I want a taper attachment for.

spridget axle.jpg

The top axle is a stock axle. The bottom axle is a growlerized axle.
 
Growlerizing! I love it! I just learned my new thing for the day
Mark
 
The name growlerizing came from a midget racer down in OZ whose handle was Growler. This was a known fix in the race circles for quite some time but not known to the masses. Growler spread it far and wide on internet forums devoted to midgets and sprites.
 
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