Hi,
This thread has become a go-to search result resource for folks to get info on tapered dead centers for various older horological lathes. Awesome.
But, we
never went on to catalog anything, so I'd like to reinvigorate
"It would be a good idea if ones among us that are able to accurately measure tapers on their lathes and their accessories, would report the tapers measured so that a table of a kind can be produced that may contribute in correlating the tapers across various manufacturers."
If it's already been done, can someone please post a link? Maybe it's all listed in one of those great old lathe books?
If not, here's what I found for
Leinen (a.k.a.
Boley & Leinen --or B&L) sold in the USA by Henry
Paulson & Co., but mostly smaller units and a narrower range of add-ons. Other great German lathes
Wolf Jahn,
F. Lorch and
G. Boley (slightly different from Leinen - or B&L - often confused) are sadly no longer being made, though good info is available on
www.lathes.co.uk and youtube/sites, like Steffan Pahlow, Niels Machines, etc. But, the modern German firm Boley GmbH at
www.boley.de (no idea on the name there) still sells Leinen 8mm WW pattern lathes and components, and they also provide data on the tapers! The thing is...there are several different Leinen tapered components available today (and in the past) --and the angles do not appear to be cut from different axial sections of a single tapered cone.
Also, of many sites for folks working with machine tapers, a good one is
www.magafor.com/841/uk.htm And, to help out those who want to cut their own, RDG sells an affordable 8mm WW style live male center for G. Boley lathes that fits many other makes, which is great for cutting tapers. OK, so for
Leinen, B&L, and Paulson, there are (at least) four different kinds of tapered components:
1) the larger diameter (like 4mm-ish) and stubbier
3°30' components that fit into a) the Leinen (B&L) "a30e" crank tailstock, b) more recent versions of the 8mm "sleeve" tailstock runner, and c) a big-bore Leinen WW style 8mm collet. These components are like rose cutters, fine-work tips/points and the D bit countersinks/cutters/drills, as well as the drill pad, male and female dead (and now live) centers, etc. This taper value can be used to cut any "bigger" sized Leinen (B&L) component replacements folks may want. I don't have any newer/big G. Boley stuff, like the F1, but maybe those also use this same taper?
2) there are much thinner tiny bits (like, 2mm-ish) that fit into a center of the Leinen (B&L) WW style safety roller, and were (previously) also sold with an eccentric/offset 8mm runner for their sleeve tailstock. All bits were sold with their receivers in a set of 6 or 12, and tapered at
2°34' With this, we can make replacements, as these safety rollers are not hard to find used, but are usually missing the good stuff.
3) there are the pair of centers (m/f) that come with the Leinen (B&L) "Drive Plate," often with pig tails for ejection out via a finger. These are used with a carrier/dog, for turning between centers. These are part of the drive plate, but unlike the tiny inserts, the taper angles were
not provided at boley.de.
4) the typical "regular guy" long, thin (like 2 to 3.5mm) old-fashioned m/f dead centers which fit the old small-bore tapered hole/center collets. These collets and their centers are no longer sold by Boley GMBH, so they are obsolete. My
guess is these would have been copied exactly by Leinen from G. Boley a hundred or so years ago, and might be 1:12, as suggested in the post above. The Paulsons fit interchangeably in my Leinen's (and B&L's), but I am not 100% sure on Leinen being 1:12. According to the online calculator, and if I have it all right, 1:12 has a cone angle of
4°46' and I think this means the taper is losing/gaining 1mm in diameter for every 12mm of axial distance (or half that -- .5mm for every 6mm of travel, which is easier to measure on short components, like these old centers). Please correct me if I'm mistaken, as this is all new to me, I'm not an engineer, and my Leinen stuff is all mothballed in storage, so I also have no direct measurements.
As requested earlier, please jump in with anything that helps us all understand this stuff better?
All the best...