Unipart Profile Categories
The U-numbers can be found in my book, Collector's Guide for Porcelain Insulators. U-Chart represents all the various unipart U.S. pin-type insulator styles and is separated into the categories below. Some examples are shown for each category.
U-2 to 43 - Pony
U-46 to 76 - Exchange
U-81 to 85 - Duplex
U-89 to 100 - Mine
U-104 to 121 - Toll
U-132 to 160 - Beehive
U-164 to 172 - Haystack
U-173 to 175 - Dry-spot
U-180 to 180B - Stovepipe
U-181 to 187 - Self-Tying Patent Top
U-189 to 189B - Vertical Conductor
U-190 to 190B - Dummy Pothead
U-191 to 219A - One-Part Transposition
U-220A/B to 225A/B - Two-Part Transposition
U-228 to 274C - Signal (Skirt rest hat)
U-277 to 337 - Signal (Petticoat rest hat)
U-339 to 339C - Ring Top (no-tie)
U-342 to 344B - Curved Wide Hat
U-348 to 351 - Grooved Hat
U-353 to 363 - Mushroom
U-366 to 370 - Straight Wide Hat
U-372 -Provo
U-376 to 376D - Etheridge Patent
U-377 to 383 - Roman Helmet (no inner skirt)
U-384 to 390 - Roman Helmet (double petticoat)
U-392 to 394 - Minnie Mouse
U-395 - Mickey Mouse
U-396 to 400B - Loop
U-401 to 401C - Fay Clamp and Clamp Top
U-402 to 414 - Heavy Cable Top
U-416 - Under Cross Arm
U-418 to 419 - Fog Bell
U-421 - Rugged Bell
U-425 to 433B - Pin Post
U-436 to 452 - Straight Cable
U-457 to 497B - Straight Cable (extended inner skirt)
U-498 to 503 - Truncate Cable
U-506 to 534 - Feeder Cable
U-537 to 579 - Curve Cable
U-581 to 596A - Pogo
U-597 to 622 - Crown Cable
U-623 to 625A - Peaked Crown Cable
U-626 to 699 - Curve Cable
U-701 to 718 - Triple Petticoat Cable
U-720 to 774 - Triple Petticoat Cable (extended inner skirt)
U-776 to 779 - Hi-Top (Side Tie)
U-780 - Lapp and Pinco Transposition
U-782 to 805 - Hi-Top Cable
U-807 to 818 - Fog Type
U-819 - Helical
U-820 - Spiral
U-821 to 844 - Fog Type
U-846 to 861 - Fog Bowl
U-864 to 864B - Fog Type
U-865 to 909 - Two Skirter
U-912 to 913 - Three Skirter
U-922 to 969 - Early Classics (1895 -1907)
U-970 to 990 - Threadless (1850 -1880)
U-995 - Graniteware (circa 1905)
