What is the "tailstock offset method" of turning a taper?

[Nelson]

Can someone explain the steps necessary- photos would be even better.

Thanks.


Nelson

 

[chief]

Nelson do you want to know why you would want the off set??

 

[Nelson]

Nelson do you want to know why you would want the off set??

Say I want/need to make an arbor for my VN #12 mill- I would need a method to make the taper.
The arbors go for $150 or so each WHEN you can find them. When my lathe is working, I would like to try to make one.

:tiphat:Nelson

 

[Nelson]

Here you go, scroll th 64-2.

"Billy G"

https://docs.google.com/viewer?a=v&...YEzAoG&sig=AHIEtbSTHJCY4ClOsv31nUsC-6FEtGn3cA

Very nice article! Thanks!

Nelson

 

[PurpLev]

Very nice article! Thanks!

Nelson

yes -very nice article indeed - short and to the point.

 

[ScrapMetal]

The version I learned from...





From SB's "How to Run a Lathe"

-Ron

 

[Tony Wells]

Tapered arbors can be turned with that method only if they are not so long that the total offset required exceeds the distance the tailstock will set over. Some people adapt a boring head with a center that allows more travel in some cases, and does not require the realignment of the tailstock after the taper is finished.

 

[irishwoodsman]

see if this works

 

[jgedde]

To really get an accurate taper, one wouldn't use the ruler method in the book. I mount a dial indicator in my tool post and another indicator against the carriage. The latter is held with a magnetic base indicator holder. Then, by moving the carriage a known distance, say 1.000", I see how much the toolpost mounted indicator has moved. By simple trig, you can determine the precise angle, or by multiplying the toolpost deflection by 12/carriage_travel, you can determine taper in inches per foot (often how tapers are spec-ed).

If you have only one indicator, you can use your compound (set at 90 deg) to set the longitudinal travel...

Remember, tapers are specified using the included angle, so you need to machine it so that your tailstock is set to give 1/2 this angle.

To set up the taper initially, I assume my tailstock is aligned to the headstock (it is). Then, using an toolpost mounted indicator, I offset the tailstock 1/2 the required taper.

Also, with a taper, surface finish is important. CRS is tough in that department... For me, I'd use 303 SS (I have a lot) and live with the galling that could occur.

BTW, when are you gonna show us your projects? Don't be ashamed!

John

 

[ScrapMetal]

Thought I'd share this little gadget for assisting with this kind of taper operation.



Don't know much about it other than it's from Hemingway Kits: http://www.hemingwaykits.com/acatalog/Set_over_Centre.html

-Ron