Heat Controlled to 3 Degrees

Results Positive. Steel hardened at point of greatest efficiency. No breaking in hardening. No warping. Absolute uniformity. GEO. NASH & COMPANY

24 So. Clinton St., Chicago,

217 Pearl St., New York City.

JESSOP'S HIGH GRADE TOOL STEEL

Fills the Circle of Your Requirements

It possesses characteristics

that recommend it to all users of High

Grade Steel For lathe tools it is unexcelled

giving a cutting edge that will stand the highest rate of
speed with no more regrinding than is necessary with high
grade Carbon Steel-It goes through hard spots and scale
with the greatest ease.

We constantly carry in stock:

Best Tool and Die Steel-Annealed and unannealed

"Ark" High Speed Air Hardened Steel

Rock Drill Steel

Composite Die Steel

Self-hardening Steel

Double Shear Steel

Special Steel for Twist Drills

Sheet Steel of all Gauges and Qualities

Truss Spring Steel

Sheet Steel

Stéel Circular Saw Plates

Double Refined Steel

Genuine (L) Blister Steel

Importation orders taken for grades and sizes not

carried in stock.

Send for Catalogue.

Wm. Jessop & Sons, Ltd.

91 John Street, New York

W. F. Wagner, General Agent

Manufactory, Sheffield, England Branch Warehouses throughout the United States and Canada

'

PUBLICATIONS OF

The Derry-Collard Co.

NEW YORK.

PRACTICAL PAPER SERIES

TURNING AND BORING TAPERS.

Fred H. Colvin.

A plainly written explanation of a subject that puzzles many a mechanic. This explains the different ways of designating tapers, gives tables, shows how to use the compound rest and gives the tapers mostly used. (25c.)

DRAFTING OF CAMS.

Louis Rouillion.

The laying out of cams is a serious problem unless you know how to go at it, right. This puts you on the right road for practically any kind of cam you are likely to run up against. And it's plain English, too. (25c.)...

COMMUTATOR CONSTRUCTION.

Wm. Baxter, Jr.

The business end of a dynamo or motor is the commutator, and this is what is apt to give trouble. This shows how they are made, why they get out of whack and what to do to put 'em right again. (25c.)

THREADS AND THREAD CUTTING.
Colvin-Stabel.

This clears up many of the mysteries of thread cutting such as double and triple threads, internal threads, catching threads, use of hobs, etc. Contains a lot of useful hints and several tables. (25c.)

BRAZING AND SOLDERING.

James F. Hobart.

A complete course of instruction in all kinds of hard and soft soldering. Shows just what tools to use, how to make them and how to use them. (25c.)