The JIS Drawing Checklist to Run Before You Send an RFQ

Drawings / 13 Sept 2026

A firm quote and a vague one are usually produced from the same drawing. The difference is whether the shop had to assume anything.

Every assumption a shop makes gets priced. Either it prices the risk in, which makes the quote high, or it prices the easy interpretation, which makes the quote low and the first article wrong. Neither helps you.

This is the checklist. Twelve items, ten minutes, and it works on a drawing you did not draw.

1. General tolerance class

Find the title block note. It will look like JIS B 0405-m or ISO 2768-mK.

Present? Good. State it in the enquiry email anyway.
Missing? This is the single most expensive omission on any drawing. Decide the class and say it explicitly. Medium is the sensible default for most machined parts.
Too tight for the part? A blanket fine class on a bracket costs money on every piece forever. If three features need precision, tolerance those three and set the general class to medium.

The values are in the general tolerance guide.

2. Geometrical tolerance class

The letter appended to the same note, H, K or L, points at JIS B 0419. It applies whether or not any geometric symbol appears on the part.

The H class run-out limit is 0.1 mm and the H class flatness on a 200 mm face is 0.2 mm. Both are tighter than people expect from a note nobody reads.

3. Projection symbol

JIS B 0001 specifies third angle projection, the same as ASME. Most European drawings are first angle.

Check the truncated cone symbol is present in the title block. If it is not, add a note. A shop that habitually works to first angle drawings can place a feature on the wrong side of the part, and that survives all the way to inspection.

4. Material designation and what you will accept

SUS316L alone leaves the shop to decide what it buys. Better:

SUS316L per JIS G 4303
EN 1.4404 or ASTM A276 Type 316L acceptable

If no substitution is acceptable, say that instead. Silence gets read differently by every shop. The equivalents table has the mapping.

5. Product form

The grade designation is the same for bar, plate and sheet. The standard differs, and so does the price and the grain direction.

If the part must come from bar, say so. If plate is fine, say that too, because it may be cheaper in your size.

6. Certificate level

State it explicitly:

No certificate
Mill certificate
EN 10204 type 3.1
Heat lot traceability required
First article inspection report
Full CMM dimensional report

Each is real cost. Asking for all of them by default on a bracket is money spent on paperwork. Asking for none on a part that will be audited is a problem later.

7. Surface finish call-outs

Check what is actually on the faces.

Ra or Rz values? Clear, no action needed
Triangle symbols? Legacy notation. Get the intended Ra confirmed in writing before anyone quotes. See JIS surface finish symbols
A blanket note applying a tight finish to everything? Split it. General finish once, exceptions on the features that need them

8. Thread call-outs

Every thread needs size, pitch and class:

M10 x 1.25 - 6H, thread depth 20 min, drill depth 25 min

M10 alone gets you coarse pitch and whatever class the shop’s tap happens to cut. Details in the thread callout guide.

9. Surface treatment

Passivation, electropolishing, bead blasting, plating, anodising on adjacent parts. Each is an outside process with its own minimum lot and lead time.

Passivation on stainless is normally specified to ASTM A967 or AMS 2700, even on a JIS drawing, because JIS has no equivalent in common use. Give the method as well as the standard: nitric or citric.

If electropolishing is specified, give the target Ra. Otherwise every shop assumes a different one.

10. Heat treatment and sequence

If the part is hardened or aged, the sequence is part of the specification:

Supply in condition A
Harden to 58 to 60 HRC after rough machining
Grind critical diameters after heat treatment

Without this, a shop can legitimately quote machining the part complete and heat treating it last, which will not hold your dimensions. See SUS630 machining and SUS440C and SUS420J2.

11. Quantity, and whether it repeats

Not a drawing item, an enquiry item, and it changes which shop should quote.

Below about 20 pieces, setup dominates and a small shop is usually the right fit
A few hundred and dedicated tooling becomes justifiable
A repeat annual volume changes the pricing conversation entirely

Give the real number. A shop that quotes 500 and receives an order for 5 will requote, and the second number will be higher.

12. Anything the drawing does not say

Three things live outside the drawing more often than they should:

Magnetic permeability. Cold work raises permeability on austenitic grades. If the part goes near a sensor or into a vacuum chamber, put the limit on the drawing, for example mu below 1.05, not in an email after the quote.

Cosmetic requirement. Ra is a roughness number, not an appearance specification. If a face has to look a particular way, describe it and supply a boundary sample.

Packaging. Stainless parts that arrive scratched are rejected as often as parts that arrive out of tolerance. Individually bagged, interleaved, or bulk in a box are three different costs.

The short version

Before the drawing leaves your desk, you should be able to answer these without looking:

What general tolerance class does it carry, dimensional and geometrical?
Which grade, which standard, and will I accept an equivalent?
What certificate do I need?
What surface finish, on which faces?
Are the threads fully specified?
Is there a treatment or a heat treatment, and does the sequence matter?
How many, and does it repeat?

If any answer is “the shop will work it out”, that is the item to fix first.

Want it checked by someone else? Get a quote. An engineer runs this list before the drawing is placed with a shop, and comes back within 24 business hours with either a priced quote or the specific questions that need answering first.

Questions

How long does this checklist take?

Ten minutes on a drawing you already have. It is faster than one round of quote clarification emails, and much faster than a first article that fails.

Should I fix the drawing or just add notes to the enquiry?

Notes in the enquiry work for a one off. If the part will be reordered, fix the drawing. Every future enquiry inherits the fix.

What if the drawing is not mine to change?

Then send it as it is and put your clarifications in the enquiry email, clearly marked as clarification rather than as a change. Never redraw someone else's drawing to make it easier to quote.

Which item causes the most trouble?

The general tolerance class, by a wide margin. It is one line in the title block and it governs most of the dimensions on the page.

Have a drawing for a stainless part?

Send it and an engineer reads the title block, quotes it within 24 business hours, and if you order we place, manage, inspect and ship the parts on one PO and one invoice.

Get a quote