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Counter Questions

The questions we answer at the counter every day — in plain English. If yours isn’t here, call or bring the part in; we’ve probably answered it before.

Fifty years behind the counter means we hear the same good questions over and over. Here are the most common ones, answered the way we’d answer them in person — no jargon, no judgment. Tap a question to open it — most answers come with a picture.

Sizing & measuring

How do I figure out what size bolt I have?
lengthdia.threads per inch

Three measurements get you there — the diameter (across the shank), the thread pitch (threads per inch), and the length. Length is measured differently depending on the head, so check yours. Or just bring it in and we’ll size it in seconds. How to measure a fastener →

It looks like a ¼″ but won’t thread — could it be metric?
5/16″M8line upout of step → binds
Drawn to scale: nearly the same size, but the threads drift out of step.

Very likely. A few sizes are near-twins — an M8 is almost exactly a 5/16″, and an M6 is close to a ¼″. They start, then bind. If a bolt threads a turn or two and fights you, stop and check the system. Metric vs. inch →

Do I measure the length from under the head or the whole bolt?
lengthHEX, ROUND, PANlengthFLAT (COUNTERSUNK)

For a regular hex, round, or pan head, measure from under the head to the tip — the head sits on top and doesn’t count. For a flat (countersunk) head that sinks flush, measure the whole thing, head included. Measuring a flat-head →

What size wrench does this bolt take?
¾″ wrench½″ bolt
Wrench size = across the flats, not the bolt’s diameter.

The wrench size is the distance across the flats of the head, not the bolt’s diameter — a ½″ bolt takes a ¾″ wrench. The matching nut takes the same size. Wrench & socket chart →

Threads

Is this a coarse or fine thread?
coarsefine1 inch
Count crests over one inch: fewer = coarse, more = fine.

Count the threads against a ruler over one inch — fewer is coarse, more is fine. Each diameter only comes in a couple of pitches, so once we know the size we narrow it fast. Or drop it on our thread gauge. Thread pitch chart →

I need to tap a hole — what drill do I use?
tap drill holetap cuts threads out to bolt size

It depends on the thread. Our chart gives the right tap drill for a clean, strong thread at every common size. Thread pitch & tap-drill →

Strength & grades

What do the lines on the bolt head mean?
Grade 2no linesGrade 53 linesGrade 86 linesA325letters

They’re the grade — how strong it is. No lines is a Grade 2, three lines is a Grade 5, six lines is a Grade 8; structural bolts carry letters like A325. Higher grade = stronger bolt of the same size. Bolt grades chart →

Is a Grade 8 always better than a Grade 5?
✓ Match itThe safe move is to match the grade you’re replacing.
~ Step upOnly when a design calls for it. Grade 8 is stronger, but harder, a bit more brittle, and pricier.
✗ Step downDropping to a weaker grade is how joints fail.

Stronger, yes — but harder, a bit more brittle, and pricier. Thread, grade & finish →

What nut goes with a Grade 8 (or A325) bolt?
Grade 8 boltGrade 8 or A563 DH nutA325 / A490 boltDH or 2H heavy hex nut

One at least as strong as the bolt — a soft nut strips before the bolt does its job. Grade 8 wants a Grade 8 or A563 DH nut; A325 and A490 want a DH or 2H heavy hex nut. Nut compatibility →

How tight should I tighten it?

It depends on the bolt’s size, grade, and lube. Our torque estimator gives a starting point — but if a manual or gasket calls out a torque, always use that. Torque estimator →

Finish & rust

What’s the difference between zinc and galvanized?
Zinc platedthin & shinyHot-dip galvanizedthick & roughsteel

Both are zinc coatings — zinc plating is thin and shiny for indoor/light use, hot-dip galvanizing is thick and rough for outdoor and structural work. Finish guide →

Can I put a stainless bolt with a regular steel nut?
✓ Match metalsStainless with stainless, steel with steel.
✗ Mixed in a wet spotStainless and plain steel together can speed up corrosion.
~ Stainless on stainlessCan gall (seize) if run fast and dry.

Best to match metals. Mixing stainless and plain steel in a wet spot can speed up corrosion, and stainless-on-stainless can gall (seize) if run fast and dry. Tell us the environment and we’ll match the set. Nut compatibility →

Will these rust if they’re outside?
Plain steelrusts outsideHot-dip galvanizedoutdoorsStainlessoutdoors

Plain steel will — the finish is what fights rust. For weather and outdoor work, you want hot-dip galvanized or stainless. Finish guide →

Anchors, flanges & specialty

Which anchor do I use for concrete?
Solid concreteHollow blockDrywallwedge · sleeveconcrete screw (lighter)toggletoggle

It comes down to the base material and the load — wedge and sleeve anchors for heavy holds in solid concrete, concrete screws for lighter removable work, toggles for hollow block or drywall. Choosing an anchor →

My self-tapping screw just spins and won’t bite — why?
STEEL TOO THICKthreads hit first → spinsPOINT BREAKS THROUGHthen threads bite

Usually the steel is too thick for that screw’s drill point, so the point never breaks through before the threads hit. Step up the point size, or pre-drill and use a thread-cutting screw. Tapping screws →

How many studs and nuts does my flange take?
nutnuttwo nuts per studstud count set by size + class

That’s set by the flange size and pressure class. Our chart gives the stud count, size, and nut count (two per stud) for Class 150 and 300. Flange stud & nut chart →

How do I get this security screw out — I don’t have the bit?
pin-in Torxspannertri-wingone-waybuilt not to come out

Most tamper-resistant drives (pin-in Torx, spanner, tri-wing) just need the matching security bit, which we can identify and supply — bring the screw or a photo. One-way screws are the exception; they’re built not to come out. Drive & security ID →

About J&E

Can you make a bolt I can’t find anywhere?

Often, yes — that’s what the machine shop is for. Send us a print, a sketch, or the broken part and we’ll quote it. Custom machining →

Do I have to buy a whole box, or can I get just one?

If you truly need just one, we’ll break a box and sell you one — we’re not going to send you down the road over a single bolt. Here’s the honest tip, though: the package (standard) quantity is where the best price is. A full box or carton has the lowest cost per piece, while ones and twos take more to pull and ring up, so they cost more each. If you need more than a handful, ask for the package count — it’s almost always the better buy.

Didn’t see your question?

Bring the part or a photo to either counter, or give us a call. Fifty years in, there’s a good chance we’ve answered exactly your question before.

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