Line-and-Shaft vs. Electric Motors

nw-mailing-list at nw-mailing-list at
Thu Apr 20 12:37:53 EDT 2006


Changing the shop from line-shaft drive to electric motors at each
machine tool would need consideration of how the line shafting was
powered (steam driven? Or a very large electric motor?), what space was
available for the new electric motors, and whether the machine tools
could be converted easily to this new drive arrangement.

I used to work for the old LeBlond Machine Tool Company and used a 7 hp
Westinghouse AC motor that was made in 1910, if I remember correctly.
It was about 4 feet in diameter and about 3 feet in width. Using motors
of this size might have been inconvenient in the available shop space.
Electric motors got a lot smaller in the 1920's as the technology

Many line shaft machines used "cone drive' sheaves or stepped diameters
on the sheaves to achieve speed changes. The operator had a wooden
'pusher', much like a draw knife, to move the leather belt from one size
to the other. If the shop converted a machine form belt drive to
electric motor drive, some arrangement had to be made to the new drive
to retain the ability to change the driving speed.

As you can see converting a shop over is not very simple. Either new
machine tools need to be bought or some significant reworking of the old
machine tools was necessary.

It is more likely that the shop converted over by replacing old,
obsolete machine tools with new electric motor driven tools and wiring
the shop for that machine tool and dismantling the line shafting over
that tool. Over time, the shop would change out most of the line-shaft
drive tools until it became unfeasible to keep the line-shafting running
for the rest of the shop.

In the 'teens and '20's machine tool design and performance, horsepower
increases, tolerance capability and speed of production, increased
tremendously. Keeping old line shaft drive tools would deny the shop
these productivity increases. Management certainly would have
considered that in deciding what to do.

Also, line shafting and belting was DANGEROUS to be around as the belts
could not have guards around them due to the need to shift speeds by
shifting belts.

As to the horsepower that could be transmitted by leather belts, they
could be quite good as leather makes an excellent transmission belt.
50-75 horsepower was possible. Large planers and vertical turret lathes
and wheel lathes/ gap bed lathes would use that amount of horsepower.

In some shops using specialized machinery, line-shaft drive lasted into
the 1960's as replacing the special machines with new was not feasible,
i. e. no machine tool company made anything like them anymore!

Gary Rolih

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From: nw-mailing-list-bounces at
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Sent: Thursday, April 20, 2006 10:14 AM
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Subject: Line-and-Shaft vs. Electric Motors

Since we are now blessed with "East End Shop" representation on the
List, perhaps someone has information on the following topoc.

I've been wondering when Roanoke Machine Works/East End Shops made the
transition from "line-and-shaft" power to electric motor power for the
operation of its machinery.

By "line-and-shaft" I mean the old system of powering machinery in the
days before electric motors. In the line-and-shaft method, power is
distributed through a building from a stationary steam engine through a
system of rotating rods, gears and flywheels suspended from the roof
trusses. Individual machines are connected to this constantly rotating
system by a leather belt, which belt may be engaged or disengaged from a
flywheel on the line-and-shaft by use of a hand clutch lever.
Line-and-shaft systems were maintained by a craft called "millwrights."

Can you imagine trying to bore a large diameter hole or run a milling
machine using this old system?

The only line-and-shaft I know of that's still in existence is in the
old East Broad Top RR shop at Orbisonia, Pa., but, of course, it hasn't
operated in years.

I've always nwondered about when the transition to electric motors for
shop machinery took place, as my own great-grandfather was a machinist
at Roanoke Machine Works from about 1882 to 1934.

Has anyone seen any documentation on this major change in the way of
doing things?

-- abram burnett

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