M3–M16 metric
Mild steel, SS, ali
In-house
Tapping, made in Bolton.
Clean metric threads in pre-punched or drilled holes — M3 to M16. Done in-house alongside your punching and bending so there's no second supplier and no second delivery.
Secondary machining
Threads cut in-house — no second supplier.
Tapping converts a plain hole into a threaded one. It sounds simple, and for the most part it is — but it needs to be done in-house to keep your job in one place. Sending parts to a sub-contractor just to add threads means a second collection, a second delivery, a second invoice, and more time before anything gets assembled.
We run two dedicated tapping machines alongside our punching and bending operations. The SFX SFX-M16R automatic tapper handles volume work cleanly and repeatably up to M16. The Fobco Emuge GR3 is a precision bench tapper used for smaller batches, tight-tolerance positions, and anything requiring care. Both machines use the same taps — coarse metric, standard pitch, M3 to M16.
If you're sending a job for punching or bending, tapping can run in the same order. One quote. One delivery. Parts arrive with threads in.
Capability
Tapping specifications.
What we can cut and on which machines. Coarse metric as standard — call us for fine pitch.
MachinesSFX SFX-M16R · Fobco Emuge GR3
Thread rangeM3 – M16 metric coarse
Fine pitchAvailable on request — confirm at quote
In-turret tappingAvailable on Amada EMZ 3510 (punch press)
Thread typeThrough and blind holes
MaterialsMild steel · Stainless steel · Aluminium · Galvanised
Min. sheet thicknessTypically 2× thread pitch — confirm at quote
Lead time5 working days standard
Tap vs alternatives
When to specify tapped holes.
There are three ways to get a threaded hole in sheet metal. Here's the honest split.
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Tapping — thick material or post-bend
Use tapping when the material is thick enough for solid thread engagement (typically 3mm or more for most M-sizes), when existing drawings already specify tapped holes, or when the feature needs to be added after bending and the turret punch can't reach the position. Our drill presses can also pre-drill for tapping in the same operation.
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In-turret tapping — flat parts, volume runs
If your part is flat and the tapped holes are punched in the same operation, in-turret tapping on the Amada EMZ 3510 is faster and more cost-effective for volume. The turret forms the thread without a separate operation. Best for M3–M10 in material up to about 3mm.
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Clinch fasteners — thin material, high loads
For thin sheet (under about 2mm) where tapped threads won't give enough engagement, self-clinching nuts give full thread depth regardless of sheet thickness. If you're not sure which is right for your application, send the drawing — we'll specify correctly.
For your quote
What to send for a quote.
The more clearly the threads are called out on your drawing, the faster and more accurate the quote.
- A DXF or dimensioned drawing with hole positions and sizes — we need to know where each thread goes and what diameter to pre-drill.
- Thread spec — M-size and whether it's coarse or fine pitch. Coarse is standard; call out fine pitch specifically.
- Through or blind — through is standard. Blind holes need a depth specified.
- Material and thickness — affects minimum engagement and whether in-turret is possible.
- Quantity — and whether this is a one-off or a repeat order.
File formats accepted
DXF
DWG
STEPPDFSketch
No DXF? A dimensioned PDF or a sketch with thread sizes called out is fine. We'll work with what you have.
Why BSM
Secondary machining in-house.
Secondary machining in-house.
Not outsourced.
Punch, bend and tap under one roof
Tapping runs in the same production order as punching and bending. No second supplier, no transit between processes, no second delivery date to manage.
One quote covers the full job
Send the drawing once. We price the punching, bending and tapping together — one number, one lead time, one invoice.
Correct thread spec, confirmed at quote
We confirm pre-drill diameter, tap size, engagement depth and feed rate at quote stage — not on the shop floor where problems are expensive.
The family trade since 1979
Sheet metal runs in the family. Bolton Sheetmetal Ltd since 2011, family-run, debt-free. Documented processes and first-off sign-offs in place — working towards ISO 9001 certification.
FAQ
Tapping, asked & answered.
What thread sizes do you cut?
M3 to M16 metric coarse as standard. Fine pitch is available on request — if you need a specific pitch, call it out on your drawing and we'll confirm.
Can you tap after bending?
Yes. Post-bend tapping is one of the main reasons to use a dedicated tapping machine rather than in-turret. Once the part is folded, our bench and automatic tappers can reach positions the punch press can't. You'll need to confirm there's access to the hole on the folded part.
What's the thinnest material you can tap?
Generally you need at least 2× the thread pitch for useful engagement — for M5 coarse (0.8mm pitch) that's 1.6mm minimum material thickness. In practice, if the sheet is under about 2mm, a clinch nut gives better results than a tapped hole. We'll tell you which to use at quote stage.
Do you do blind or through holes?
Both. Through tapping is standard and most common. Blind holes need a depth specified on the drawing — state minimum full thread depth and we'll confirm the pre-drill depth and tap approach.
Can you supply parts that are punched, bent and tapped in one order?
Yes — that's the standard workflow for most jobs. Send the complete drawing and we route it through punch, bending and tapping in sequence. One quote, one lead time, one delivery.
Ready when you are
Need threads in your sheet metal parts?
Send us your drawing with thread sizes called out and we'll come back with a price within the working day.