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View Full Version : Telescoping Taper Atch'mt - How'deywork?



lynnl
11-29-2013, 07:53 PM
I thought I understood the workings of a telescoping taper attachment; however, a couple of days ago when I set mine up for the first time in a long while, I found that it was tapering when I expected it not to.

Ordinarily for normal lathe use, I just have the clamp (for clamping to the bed) disconnected and hanging loose. So to set up for taper turning, I would (1) connect the clamp to the bed, and (2) tighten the bolt that locks the slotted slide/draw bar to the shoe which slides along the taper guide. I thought both of those steps were essential to force the cross slide to follow the taper. But my observations did not bear that out! The taper is being followed simply by clamping the apparatus to the bed.

So what purpose is really served by locking that slotted draw bar to the shoe? Is it simply to prevent me from inadvertently moving the cross slide with the hand crank? ...which it does when the bolt is tightened.

This is a 13" LeBlond Regal. I have the manual, which includes an exploded view of the attachment and another of the cross slide. But it's still not completely clear (to me) just what all is taking place. I'm probably just not connecting all the mental dots implied by the diagrams.

Where does the telescoping action of the cross feed screw take place? Is it on the hand crank side of the cross feed nut? That area is not visible without taking the saddle off, and the diagrams don't reveal that.

A picture (not great quality) can be seen on page 17, fig 17 here:
http://books.google.com/books?id=4QEYAAAAYAAJ&pg=PA17&lpg=PA17&dq=leblond+telescopic+taper+attachment&source=bl&ots=vwOdJYEeFu&sig=7qzCZOepNsp20oYtAc6aRGtMFeI&hl=en&sa=X&ei=mz6YUp-DB8v5kQelooCICA&ved=0CG0Q6AEwCQ#v=onepage&q=leblond%20telescopic%20taper%20attachment&f=false

Thanks for any insight to be forthcoming!

trackfodder
11-29-2013, 08:20 PM
I have considered building a simple one for years but (1) I don't have much application for one and (2) I would have to remove the bronze crossfeed nut to use it each time for a short application.

TriHonu
11-29-2013, 09:32 PM
From the 1951 LeBlond "Running A Regal" manual:

http://TriHonu.home.comcast.net/TaperAttachment.png

The telescopic taper attachment is ruggedly constructed and simple to operate. When the carriage is brought into position for the taper operation:
The bed bracket (1) is tightened on the flat bed way.
The swivel guide bar (2) is adjusted to the selected taper, which is marked in inches on one end of the lower bar and in degrees on the other end of the bar.

Adjustment for selected taper is made by loosening nuts (3) and moving bar (2) to the desired taper. The swivel guide bar is held secure by the screws (3). With the taper bar clamp nut (4) loosened and assuming that the shoe bracket gib and the carriage bracket gib are properly adjusted, the tool is brought into position and the nut (4) is tightened.

We are now ready to chase taper threads or to finish taper turn, or finish taper bore. When carriage feed is engaged, bed bracket and its connecting rod hold lower taper bar and adjustable swivel bar in a fixed position with relation to bed and work. Movement of carriage slides gibbed shoe (5) along taper bar.

With lights cuts, nut (4) need not be tightened, then the pull is on the cross feed screw and nut and the end of the screw telescopes in the cross feed telescopic bush, allowing the slide to move in or out.

With the nut (4) tightened, none of the pull is on the cross feed screw, but on the flat draw bar (6) shown
over the cross feed screw, which is connected to the bottom slide.

This relieves the cross feed screw of all strain and pull and wear, and insures longer life and retains the original accuracy of the screw.

Adjustment of the cut is made by loosening clamping nut (4) and setting tool to proper diameter and, of course, tightening nut again after adjustment is made.

Most adjustments of the tool are made by the compound rest. There is no necessity of adjusting clamping nut after taper is set, other than to adjust for depth of cut when using the cross feed screw. And this may be eliminated by using the compound rest screw.

Don Young
11-29-2013, 10:44 PM
The feed screw telescopes at the front between the handle and the nut. The screw is secured lengthwise at the back by the taper attachment and thus can move forward and backward as the taper attachment slides. This allows size adjustment by the hand wheel unless the top clamp is locked, the hand wheel can rotate the screw while still allowing it to move in and out.

lynnl
11-30-2013, 08:48 AM
Thanks guys!
Now it all makes sense. That's consistent with what I'm seeing.

I can't find any date on my xeroxed copy of the Running a Regal manual, but I looked through it again and it does not contain the info TriHonu posted above. In my copy the last numbered figure is 15 ("adjusting headstock spindle"); the exploded views of various components are not numbered.

I'm obviously missing some pages. Alternating pages of my book are hand numbered, where the copying process cut off the page number.

TriHonu
11-30-2013, 07:20 PM
I have copies of the 1931, 1948 and 1951 editions of Running A Regal in PDF format. If you want me to email you copies, just send me a PM with your email.

lynnl
12-01-2013, 09:11 AM
I have copies of the 1931, 1948 and 1951 editions of Running A Regal in PDF format. If you want me to email you copies, just send me a PM with your email.

Thanks, I would greatly appreciate that, Trihonu.
I sent you a PM.