Quick answer:

The lathe shown here does not have a Webster Whitcomb bed.

Reform series lathes were available in either Geneva pattern, or like this ^^^

MichaelG.

Apologies … I evidently mis-understood your opening post.

MichaelG.

One of my books has a chapter on lathe bed design, and, of course, I can’t find it!

From memory, there is no “right answer”, because each design balances pros and cons.  Typically: cost, strength (degree to which sag and twist are resisted), accuracy, precision, resetability, smoothness, and how well the saddle and tailstock are secured.   Multiple compromises possible, for many different reasons!   And some designs are proprietary, with a strong suspicion it was done for commercial reasons;  customers finding a few years after purchase that “only our accessories will fit”.

WW vs M – some thoughts

The book doesn’t get into Watchmaking lathes but looking at the WW and M bed profiles, I suggest:

• Both have similar strength and precision
• The WW style requires more machining than the M, hence more expensive.   Benefit is the bevels are further apart to resist rocking, and an accessory rail.
• The M-style bed is a valid simplification rather than a cheapening.   I guess the bevel position simplifies the design of the tailstock too, and anything else that clamps on to the bed.  Savings that can be passed on to the customer or added to the profits!
• Just a guess.  When these lathes were sold new:
  • traditionalists with plenty of cash would prefer the WW.
  • Cost conscious modernisers might prefer the M.

Other Examples

The book goes into flat-bed vs trapezoidal forms, and concludes flat-beds are inferior.  Originally flat beds were easier to make, but I think advances in grinding technology mean trapezoidal beds aren’t particularly difficult or costly today.

Also discusses gap vs girder beds.  Gaps add utility but weaken the structure, which needs to be strengthened underneath and this isn’t always done well.  Girder beds are stronger and easier to make, but they restrict the size of what can be turned.   Book concludes in favour of girders because they are more rigid.   Advice is buy a bigger lathe, don’t compromise with a gap.   But the book was written for manufacturing purchasers, not hobbyists, who might well vote “gap”.   What’s good and bad in lathes depends hugely on what they are used for.

If more is found about M vs WW I’d be interested to know.  Might be necessary to search the company archives for the paperwork.  Patents are often informative too. I struggle to find them, Michael is far better!

Dave

Thank You, rjenkinsgb

MichaelG.