When you're holding a worn part and the machine's ID plate is gone, identification works backwards from the part itself: determine which system it belongs to, then measure the one or two specs that make it unique — thread size, mesh count, or orifice diameter. The single most useful fact for airless gun parts: Graco, Titan, Amspray, and roughly 99% of post-1998 SprayTech and Wagner guns use a 7/8-inch thread. Pre-1998 guns may use 11/16-inch, which isn't interchangeable without an adapter.
Most parts guides assume you already know your model number. This one assumes you don't — that you're holding a worn component, the ID plate is illegible or missing, and you need to figure out what it is before you can order a replacement. That's a solvable problem, and it takes about ten minutes with basic tools.
1. Step One: Identify the System
Before measuring anything, determine which functional system the part belongs to. This alone eliminates most of the catalog:
| If the part is… | It belongs to… | Key identifying spec |
|---|---|---|
| A small mesh cylinder or cone | Filtration | Mesh count (60, 100, etc.) |
| A hardened insert with a tiny oval opening | Spray tip | Stamped 3-digit number |
| A threaded metal fitting | Hose / fluid connection | Thread type and OD |
| A rubber or PTFE ring | Seals / O-rings | ID, OD, cross-section, material |
| A hardened ball or seat | Valve assembly | Ball diameter, seat material |
| A stack of layered seals | Pump packings | Rod diameter it fits |
2. Thread Size Identification
For gun-side components — tip guards, extensions, tip bases — the thread standard is the deciding factor, and there are really only two in common use:
Graco, Titan, Amspray, and roughly 99% of SprayTech and Wagner guns made after 1998. If your gun is reasonably modern, this is almost certainly what you have.
Found on older guns manufactured before 1998. Still special-orderable, but not interchangeable with 7/8-inch components without an adapter.
Telling them apart is usually possible by eye once you've seen both, but a ruler across the gun head or tip base settles it definitively. When a listing offers a thread-size choice, measure rather than guess.
Measuring an unknown thread properly
- Measure the major diameter with calipers — the outer diameter across the thread crests for a male thread, or the inner diameter for a female one.
- Determine the pitch using a thread pitch gauge: hold each blade against the thread until one meshes perfectly, then read the TPI from the blade.
- Check whether it's straight or tapered. Pipe threads (NPT) taper; fastener threads are straight. This is often visible by eye along the thread length.
- Cross-reference diameter and pitch together against a thread chart. Neither number alone is sufficient.
- Verify by hand with a known fitting — carefully.
If a known fitting doesn't thread on smoothly by hand, it isn't the right size. Forcing damages both parts and makes future identification harder — and it can create a false sense of confirmation on a joint that will leak under pressure.
3. The NPT Look-Alike Trap
This one catches experienced people regularly, so it's worth stating plainly:
A thread pitch gauge cannot distinguish between them — both read 18 threads per inch. You need the outside diameter measurement to tell which one you're holding. Measuring pitch alone and assuming you've identified the fitting is one of the most common causes of an ordered fitting that doesn't fit.
A related quick test when you're unsure whether a thread is metric or imperial: measure the major diameter and check whether it lands on a clean metric number (6.0, 8.0, 10.0 mm) or a clean fraction (1/4", 3/8", 1/2"). If it lands cleanly on neither, you may be dealing with a British standard thread rather than either.
4. Filters: Reading Mesh Count
Filters are among the easiest parts to identify because mesh count is usually the only variable that matters, and higher numbers mean finer filtration.
| Mesh | Typical Application | Example Part |
|---|---|---|
| 60-mesh | Standard latex, general contractor work | 288749 gun filter 243080 manifold filter |
| 100-mesh | Fine finish coatings, lacquers, varnish | 288750 gun filter 238562 tip filter |
| Inlet screen | Coarse bucket-side filtration | 288716 3/4-inch inlet strainer |
The internal filter cavity is standardized across nearly every current Graco gun model, which makes gun filters one of the few components you can order confidently even with incomplete machine information — you mainly need to know whether you want 60-mesh or 100-mesh.
5. Tips: Reading the Number Stamp
Spray tips carry their own identification stamped directly on them, which makes them the easiest part on this list to identify — assuming the stamp is still legible.
The three-digit code is readable without any tools: the first digit doubled gives the fan width in inches, and the last two digits give the orifice size in thousandths of an inch. A tip stamped 515 sprays a 10-inch fan through a 0.015-inch orifice.
| Stamped Number | Decodes To | Order As |
|---|---|---|
| 515 | 10" fan, 0.015" orifice | LTX515 |
| 517 | 10" fan, 0.017" orifice | LTX517 |
| 519 | 10" fan, 0.019" orifice | LTX519 |
| 415 | 8" fan, 0.015" orifice | LTX415 |
| 310 | 6" fan, 0.010" orifice (fine finish) | FFLP310 |
Don't guess from the physical opening — a worn orifice reads larger than its original size, which is exactly why the tip needs replacing. Work from the coating you spray and the surface type instead, and treat it as choosing a new tip rather than matching the old one.
6. The Full Identification Workflow
Categorize before measuring
Filter, tip, fitting, seal, valve, or packing? This narrows thousands of parts down to dozens before you pick up a caliper.
Look for existing markings
Tips carry stamped numbers. Filters often have mesh printed on the housing. Check the part in good light before assuming it's unmarked — and remember that numbers cast into metal are usually foundry marks, not orderable part numbers.
Measure the defining spec
Thread parts: major diameter plus pitch. Seals: ID, OD, and cross-section. Packings: the rod diameter they fit. One accurate measurement usually beats three approximate ones.
Photograph the part next to a ruler
If you end up calling for help, a photo with a visible scale reference lets a parts advisor identify most components in under a minute. This is by far the fastest path when measurement is ambiguous.
Confirm against the compatible-models list
Before checkout, check the listing's compatibility section against whatever machine information you do have — even a partial model name is a useful cross-check.
Still Not Sure What You're Holding?
Call 713-931-4102 with the part in hand, or browse the interactive diagram if you know your machine model.
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Frequently Asked Questions
What thread size do airless spray gun tips use?
Most modern airless guns use a 7/8-inch thread — Graco, Titan, Amspray, and roughly 99% of SprayTech and Wagner guns made after 1998. Pre-1998 guns may use 11/16-inch, which isn't interchangeable without an adapter.
How do I identify a paint sprayer part with no model number?
Work from the part itself: measure major diameter and thread pitch, note material and any mesh or orifice markings, and identify which system it belongs to. A category plus one measured spec usually narrows to a single part number.
Why can't I tell 1/4-inch and 3/8-inch NPT apart by thread pitch?
Both have the same 18 threads per inch, so a pitch gauge can't distinguish them. You need the outside diameter measurement to tell which one you have.
Is it safe to test-fit a part to confirm the thread size?
Only by hand, and only gently. Stop immediately if you feel resistance — forcing a mismatched thread damages both parts and makes future identification harder.