# How do I cut a taper?



## wquiles (Oct 11, 2006)

Specifically, on this mini-me M6 tube, the large hole for the lamp I cut straight, but in reality it is a larger diameter on the side facing the head. To cut the hole identical to the M series neck, I have to cut a taper:









My guess is that I can put a boring tool on the left side of the holder, and then angle the tool holder to equal the taper I need. Then I would move the boring tool in-out, and then move the whole cariage to the left a "little" bit, and repeat. Kind of hard to explain with words I guess :candle: 

Ideas/suggestions?

Will


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## TranquillityBase (Oct 11, 2006)

PM sent


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## unnerv (Oct 11, 2006)

You can take the compound slide and set it to the desired angle to do a taper.


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## will (Oct 11, 2006)

not exactly sure what you want 

but - you should be able to angle the carriage to the desired angle.



tip - if you have a dial guage and a straight piece of stock, set the dial to run parallel to the stock, now move the carriage using the small handle, not the big wheel on the bottom. across the stock. verify that the carriage is parallel to the the stock, if it is, there is usually a flat area near the degree indicator. drill a 1/8 inch hole through the 2 parts. Now if you ever move the carriage to some other angle you can easily reset back to exact 0 by putting the back of the 1/8 inch drill through the hole.


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## PEU (Oct 11, 2006)

unnerv said:


> You can take the compound slide and set it to the desired angle to do a taper.



Ditto

if your tapper is larger than the compound slide movement, measure and repeat several times.

Or... use a CNC machine:









Pablo


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## Anglepoise (Oct 11, 2006)

On your lathe, I hope you have a carriage/saddle that moves length wise.
Then you have a cross slide that moves in and out 90 degrees to the carriage.
Sitting on the carriage is the Top slide or compound. This usually spins 360 degrees and can be locked in any position. It usually has a few inches of movement and this is what you use for short stubby tapers.


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## wquiles (Oct 11, 2006)

Perfect - I get it now. Thanks much for the tips/advice. I will play with this over the next weekend or two and see how it turns out 

Will


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## gadget_lover (Oct 11, 2006)

You'll find it's pretty painless, Will. Just make sure you do a dry run before you turn the lathe on. I once started out to taper a piece of tube (outside) and did not realize that I was taking a progressively larger bite. It finally jammed.

In your case (inside taper) you will want to start with the boring bar barely engaging the deepest part of the bore. Back it out using the compound. You then use the cross-slide to move the compound towards you the proper amount (.050 or so) and run the compound slide in again.

Did that make sense?

Daniel


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## wquiles (Oct 11, 2006)

Daniel,

Yes, it makes sense. Still, I need to now try it on my lathe. I will start with a scrap piece to practice, just like you taught me when I got started 

Will


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## McGizmo (Oct 11, 2006)

> if your tapper is larger than the compound slide movement, measure and repeat several times.
> 
> Or... use a CNC machine:



An other option for some lathes is a taper attachment. I have never used one nor have I guesed at how they work.


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## scott.cr (Oct 13, 2006)

wquiles, looks like your question has been answered, but then I see the mention of taper adapters.

Basically, to cut a long taper on the OD of a workpiece, you offset your tailstock. The workpiece is mounted between centers (driven by a lathe dog). The cutting tool still travels in a line parallel to the headstock/chuck axis, but now your workpiece is not parallel, it is at an angle to the chuck axis.

Even the lowly 7x10 mini lathe has a tailstock that can be offset to cut tapers... works real well as long as you know how much to offset!


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## wquiles (Oct 13, 2006)

Cool. Thanks Scott and Don. I guess there are various ways to do the same thing - so much to learn 

Will


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## will (Oct 13, 2006)

Keep in mind - if you offset the tailstock

you are actually bending the work in the chuck, unless you are using centers, which is unlikely with metal.

there is an adjustment on the bottom of my mini lathe tailstock. not the easiest to get back to center if you move it..


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## wquiles (Oct 13, 2006)

Don't worry will - for this being my first time I will be setting the angle on the compound. I will be taking baby steps 

Will


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## gadget_lover (Oct 13, 2006)

will said:


> Keep in mind - if you offset the tailstock
> 
> you are actually bending the work in the chuck, unless you are using centers, which is unlikely with metal.




I haven't used the offset tailstock for tapers, but the idea is that you do use centers to hold the work and a "dog" to keep it spinning. The dog clamps to the work near the headstock and engages (loosely) something on the spinde/faceplate/chuck to provide the movement.

A quote from littlemachineshop.com

"You can save a few bucks and make your own lathe dogs out of water pipe. If I need a lathe dog for a 3/4" diameter bar, I cut about a 1" length of 3/4" galvanized pipe. Then drill and tap a 10 - 32 NF hole and use a long screw to both clamp the workpiece and drive it from another bolt sticking out of the faceplate."

Micromark has a nice illustration of using a lathe dog at http://www.micromark.com/html_pages/instructions/82510i/lathe_dog.html

Daniel


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## vetkaw63 (Oct 20, 2006)

Don't worry about offsetting anything, just use the compound. Lathes are cheap, buy a decent one to start.
Mike


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