Post base · 1-5/8 in. series
P2072 — 6 × 6 in. Post Base, Single Channel
A 6 in. square plate of steel with a 1-5/8 in. single-channel socket on it and four 3/4 in. anchor holes. It stands a length of channel upright on a slab, and it is the one fitting here where the standard 9/16 in. hole note does not apply.
By Alex · Last reviewed 2026-09-25 · Spec looks wrong? Tell us.
- Base plate
- 6 × 6 in. (152.4 mm square)
- Socket
- 1-5/8 in. (41.3 mm) — single channel
- Anchor holes
- 4 × 3/4 in. (19.1 mm) diameter
- Steel
- About 0.23 in. (5.8 mm) base steel before coating; a hot-dip galvanized part measures thicker; catalog reference part 1/4 in. (6.4 mm)
- Catalog ref.
- Unistrut® GEC no. 17, pp. 85, 113
Dimensions above are the catalog specification for the reference part; the steel line is our supply. Steel grade is confirmed at quotation.
P2072-EG — electro-galvanized, zinc plating to ASTM B633 Type III SC1. Smooth bright silver. Indoor and dry service. P2072-HG — hot-dip galvanized to ASTM A123 or A153. Visible spangle, heavier edge build-up. Outdoor, wet and coastal service. P2072-PL — plain, uncoated steel. For painting or powder coating after assembly, or dry enclosed runs. Stainless — the catalog offers stainless, aluminum and fiberglass on some part numbers but publishes no standard suffix for them and says to consult the factory. Quote as made-to-order. Powder-coated — powder coating to a customer-specified RAL color. Not a catalog finish, so it carries no catalog code — the color, which parts take it and the film build are confirmed at quotation. We publish no film thickness and no salt-spray figure, because we have not measured one.
Finish list: Unistrut® General Engineering Catalog no. 17, p. 85 — finishes note. Powder coating is our option, not a catalog finish. The catalog also lists GR against this series — not quoted, see Finishes.
Pack: Packed per order. Anchors are not supplied and are not a strut item — specify them against the slab, not against this part number.
Catalog figures for the reference part, with where each one comes from. Our supply thickness is in Supply summary.
| Dimension | Catalog value (reference part) | Source |
|---|---|---|
| Base plate | 6 x 6 in. (152.4 x 152.4 mm) | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Socket | 1-5/8 in. (41.3 mm), single channel | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Anchor holes | 4 holes, 3/4 in. (19.1 mm) diameter | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Plate thickness | 1/4 in. (6.4 mm) | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Steel | ASTM A575 / A576 / A635 / A36 | Unistrut® General Engineering Catalog no. 17, p. 85 — fittings material note — also meets the physical requirements of A1011 SS GR 33 |
| Anchor hole positions | not published | The drawing carries 3 in. (76.2 mm) and 7/8 in. (22.2 mm) dimensions on the anchor pattern, but p. 113 does not fix which centers and which edges each one runs between. It is therefore not restated here as a measurement — read it off the plan view, and ask the supplier for the drawing of the part they will ship before the anchors go in. |
| Socket height | not published | Not dimensioned on p. 113. |
| Weld detail between socket and plate | not published | Not specified on p. 113. |
Read the anchor hole line carefully. The P2072 drawing prints “4 Holes 3/4 in. (19.1) Dia.” verbatim, which overrides the 9/16 in. standard note in the p. 113 page header. The thickness on this part is dimensioned on the drawing itself rather than taken from that header note, which is why its source column says so.
The rest of the post base group
Four part numbers share the 6 in. square plate and the four 3/4 in. anchor holes. What changes is the socket: single or double channel, and a taller version of each. The catalog does not give the socket dimensions of the other three, so check the socket against the channel it has to take.
| Part | Socket |
|---|---|
| P2072 | 1-5/8 in. single channel |
| P2072A | single channel, taller — detail not transcribed |
| P2073 | double channel (P1001A) |
| P2073A | double channel, taller — detail not transcribed |
Source: Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing. The catalog also prints SQ variants of P2072 and P2072A on the same page; the catalog does not fix what the SQ suffix changes, so it is not described here.
What bolts through it, and where the published data stops.
What it anchors to. Four 3/4 in. holes take 5/8 in. anchors with clearance, or 1/2 in. anchors with a lot of it. Which anchor is correct is a concrete question, not a strut question: it depends on the slab, its thickness, its edge distances and what the post carries. The catalog publishes the hole and stops there, and so do we.
Why the standard hole note does not apply here. Every General Fittings page carries a header note giving 9/16 in. as the standard hole. The P2072 drawing overrides it in print. A supplier working from the page header rather than from the drawing will produce a base with 9/16 in. holes that no anchor pattern will fit, which is why this is the first thing to settle in writing on an inquiry.
Load rating. The catalog publishes no load figure for P2072, so neither do we. A post base is a connection where the governing capacity is usually the anchor and the concrete rather than the fitting, and neither of those is a number this page can supply. Have the base checked by an engineer for anything that carries.
What the published cross-reference tables print opposite P2072.
| Brand | Published cross-reference part number |
|---|---|
| B-Line | B279 [S1][S3][S4] |
| Superstrut | AP-231 [S1][S3] |
| Power-Strut | PS 3013 [S1][S3] |
| Haydon | B-619 [S3] |
Row note: S1 prints AP231 / PS3013 without spaces; same part.
A published cross-reference number is one thing only: a number a cited document prints opposite this one, as a candidate substitute in the same catalog slot. It carries no load rating, steel grade, coating thickness or third-party listing — each manufacturer publishes those separately and they do not travel with a part number. Source documents, access dates and what to measure before you fit a substitute: Unistrut P2072 cross reference.
Source: our cross-reference dataset, built 2026-09-09 from the documents listed below.
What a P2072 actually is
A flat 6 in. square of steel plate with a short length of channel-shaped socket standing on it, and four holes near the corners for anchor bolts. A cut length of 1-5/8 in. channel goes into the socket, the assembly is anchored down, and you have a free-standing post: the base of a guard rail, a pipe rack, a sign frame, an equipment skid.
The single-channel version takes one channel. The double-channel version, P2073, takes a back-to-back pair, and the taller A variants of each exist for a deeper socket. The plate and the anchor pattern are the same across all four, which means the hole layout you drill into the slab does not change if you later go from single to double.
The anchor pattern is the whole ordering problem
Everything else about this part is easy and this one thing is not. The plate is square and dimensioned, the plate thickness is dimensioned, the socket is the channel profile. But the holes have to line up with anchors that in most jobs are already set in concrete, and once they are set nothing about them is adjustable.
The catalog drawing carries 3 in. and 7/8 in. dimensions on the anchor pattern. The catalog does not establish which of those runs between hole centers and which runs from a hole to an edge, so we do not publish a pattern here at all — there is no version of guessing that ends well when the alternative is drilling a slab twice. Read it off the plan view in the catalog, and for anything you are buying, ask the supplier for the dimensioned drawing of the part they will actually ship and check it against the setting-out before the anchors go in.
The second trap on this part is the hole diameter. The page-header standard for the whole General Fittings section is a 9/16 in. hole; the P2072 drawing prints 3/4 in. in its own right. A substitute produced by someone reading the header and not the drawing is dimensionally plausible and completely useless.
Checking an incoming shipment
Three checks, and one of them is not a measurement.
1. Measure the plate: 6 x 6 in. (152.4 mm) and 1/4 in. (6.4 mm) thick. Both plan dimensions, because a plate that has been sheared out of strip can come out rectangular. Measure the thickness on a free edge away from the socket weld.
2. Gauge the anchor holes: four of them, 3/4 in. (19.1 mm). A 3/4 in. drill shank drops through cleanly. A hole that takes a 9/16 in. bolt and not much more is the standard-note mistake described above, and it is the single most likely thing to be wrong with this part.
3. Offer up a cut length of the channel you are actually using. It should enter the socket and sit square without persuasion. This is the check that catches a socket rolled to a slightly different profile, which no external measurement of the base will find.
Before any of that, lay the base over the setting-out or over a template taken from the anchors and confirm the pattern matches. Do it on the first piece off the first pallet, not after the pallet has been distributed around a site.
Related parts
- P1000 — The 1-5/8 in. channel that goes into the socket.
- P1026 — The two-hole 90° angle for the connections further up the post.
- P1064 — The flat plate that spreads a bolt across the open face of the post.
- All post bases — The base group on the fittings table.
- Finish options — PL, EG, HDG and stainless, and which of them we can supply.
What we can quote against this part number
We do not manufacture these parts and we are not Unistrut. We source them. The item we can quote against Unistrut P2072 is post base, 6 x 6 in. plate, single-channel socket — a candidate substitute made to order by a contract manufacturer, offered for inquiry, not an original-manufacturer part.
| Dimension | Value | Source |
|---|---|---|
| Base plate | 6 x 6 in. (152.4 mm square) | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Socket | 1-5/8 in. (41.3 mm), single channel | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Anchor holes | 4 x 3/4 in. (19.1 mm) | Unistrut® General Engineering Catalog no. 17, p. 113 — printed on the part drawing |
| Plate thickness | About 0.23 in. (5.8 mm) base steel before coating; a hot-dip galvanized part measures thicker. Steel grade confirmed at quotation. | Our supply specification — not a catalog figure |
These are the published Unistrut catalog dimensions we build to, each with the page it is printed on. The thickness row is the exception: it states what we supply, not a catalog figure. They are geometry only. No load, torque or listing figure is claimed for our part: none has been tested on it, and a figure published for a Unistrut part is evidence about that part, not about ours.
Supply summary
What is known about supplying this part number, and nothing that is not. Anything missing from this list is missing because we do not have it yet, not because it was left out.
- Reference part
- Unistrut® P2072, as published in the Unistrut® General Engineering Catalog no. 17
- What we quote against it
- post base, 6 x 6 in. plate, single-channel socket — a candidate substitute made to order by a contract manufacturer, offered for inquiry, not an original-manufacturer part.
- Plate thickness
- About 0.23 in. (5.8 mm) base steel before coating; a hot-dip galvanized part measures thicker. Steel grade confirmed at quotation.
- Finishes available
- Plain, EG, HDG and stainless, plus powder coating on request.
- Documents we can provide
- A dimension drawing traced from the catalog page cited above. A material certificate on request — availability and cost are confirmed at quotation, per mill.
- Lead time
- Production lead time: 5–7 business days, ex-factory. Counted from order confirmation and receipt of deposit (or drawing approval for custom parts, whichever is later). This does not include transit.
- How to confirm fit
- Measure the incoming parts against "Checking an incoming shipment" on this page, before the carton goes into stock.
Get this part number quoted
Answer the seven lines below and we come back with our part number, finish options, lead time, packing quantity and what documentation we can and cannot supply. There is no list price — it is quoted per mill, finish and volume. The form takes about a minute and already knows this part number. We reply within one business day (Asia/Shanghai, UTC+8).
- Unistrut part number — P2072
- The brand and part number you are replacing
- Finish
- Quantity
- Destination — country, and state or ZIP if US
- Application — general support, electrical, mechanical, seismic, or a listed assembly
- Whether you need submittal documentation
No minimum order · 5–7 business days ex-factory · Reply within one business day (Asia/Shanghai, UTC+8) · Finishes: plain, EG, HDG, stainless
Prefer email? Open a prefilled RFQ in your mail client, or write to contact@channelstrut.com yourself. If the part is going into a specification that names a brand, say so — a substitute has to be accepted in writing before it ships.
Trademarks and who we are
Unistrut, B-Line, Superstrut, Power-Strut and Haydon, and the part numbers published under them, are trademarks or trade names of their respective owners. ChannelStrut is not affiliated with, authorized by, endorsed by or a distributor for any of them. Those brand names and part numbers are used here only to identify the products referred to.
ChannelStrut is run by Alex, a hardware sourcing specialist based in Fujian, China. We do not manufacture these parts — we source them from the mills that produce them. More on how the data is built: About.
Sources
The cross-brand part numbers in the cross-reference tab come from S1, S3 and S4. Every dimension on this page comes from the Unistrut® General Engineering Catalog no. 17, and the page it is printed on is given beside it.
- S1
- Divspec - Strut Fitting Cross Reference (Divspec / B-Line / Unistrut / Powerstrut / Superstrut(Thomas & Betts))
http://www.divspec.com/strut-fitting-cross-reference/
third-party aggregator · accessed 2026-09-09 - S3
- Master Distribution - Part Number Cross Reference Guide (G-Strut / Unistrut / Powerstrut / Superstrut / Erico / B-Line / PHD / Haydon), 23 pages
https://masterdistrib.com/content/PDF/Masterdistrib_Part_Number_Cross_Reference_Guide.pdf
third-party aggregator · accessed 2026-09-09 - S4
- Cooper B-Line - Strut Systems Competitor Cross Reference (BF93XR): Unistrut pp.2-12, Power-Strut pp.13-19, Superstrut pp.20-29, Kindorf pp.30-34
https://usermanual.wiki/Pdf/499295Brochure.1451337879.pdf
manufacturer (Cooper B-Line, now Eaton) · accessed 2026-09-09 · link dead, no archive
Source link no longer resolves; we keep an archived copy.
Every source above was re-checked for reachability on 2026-09-15.
Unistrut P2072 cross reference — what the published guides print opposite it, and what to measure on a substitute, or the full 126 part-number table.