Technical Foundation
What Is a Trammels and Trammel Point Set?
Trammel points are a pair of adjustable clamping heads that mount onto a wood, metal or graduated beam, letting a user scribe circles and arcs with a radius far larger than a standard compass or dividers can reach. One point acts as the fixed center pivot while the other carries a scribe or pencil tip set at the desired radius along the beam; loosening and sliding the point changes the radius, and a graduated beam allows repeatable, precise settings without re-measuring each time.
Machinist-grade trammel points use a hardened steel scribe tip for marking metal layout lines with the same precision as a height gauge or scribe, while general layout trammel sets are built for pencil marking on wood, drywall or sheet stock. Beam length is the practical limit on maximum radius, and some sets support interchangeable or extendable beams for larger layout work such as floor templates or large sheet metal patterns.
Prefer a quick quote?
Get Trammels and Trammel Point Sets Pricing in Your Inbox
Skip the search — tell us the radius range and point type (pencil or scribe) and we will come back with pricing.
| Spec | What It Means | Why It Matters |
|---|---|---|
| Point Type | Scribe (metal marking) vs. pencil (wood/drawing) | Scribe points cut a fine visible line in metal; pencil points won't mark metal reliably |
| Beam Material | Wood, aluminum, steel, graduated steel rule | A graduated beam allows precise, repeatable radius settings without re-measuring |
| Maximum Radius | Limited by beam length, commonly 12 in to 6 ft+ | Beam length sets the practical ceiling on the largest circle or arc that can be scribed |
| Point Clamping Mechanism | Thumbscrew, cam-lock, or set-screw clamp | Determines how securely the point holds its radius setting under repeated use |
| Grade | Machinist/toolmaker grade vs. general layout grade | Machinist grade holds tighter radius accuracy for precision metal layout work |
Shop Trammels and Trammel Point Sets
Browse Trammels and Trammel Point Sets Sub-Categories
Organised by point style and beam configuration. Pick a sub-category, or describe the radius you're laying out and let ChatMRO match the set.
How it works
From Half-Remembered Part Number to PO, in Three Steps.
Ask
Type an MPN, paste a spec sheet, or describe the part in plain English. ChatMRO understands engineer-speak.
Compare
Side-by-side specs, cross-references, and equivalents from multiple sources — without the clutter of endless browser tabs.
Quote & Buy
Request a quote or add to cart. Volume discounts, VAT-aware pricing, and consolidated procurement — all in one place.
Applications
Where Trammels and Trammel Point Sets Get Used
Trammel points are specified anywhere a circle or arc needs to be laid out at a radius too large for a standard compass to reach.
Machine Shop Layout
Scribing precise large-radius arcs and circles on metal stock ahead of cutting, drilling or machining operations.
Sheet Metal Fabrication
Laying out large-diameter circular cutouts and patterns on sheet stock before shearing or plasma cutting.
Woodworking & Cabinetry
Marking large arcs and circular cutouts on panels, tabletops and curved furniture components.
Construction & Floor Layout
Scribing large-radius arcs directly on subfloor or drywall for curved wall and ceiling layouts.
Tool & Die Making
Precision radius layout on die blanks and fixture plates ahead of machining to final dimension.
Pattern & Template Making
Creating full-scale circular templates and patterns for foundry and fabrication pattern shops.
FAQ
Trammels and Trammel Point Sets Questions, Answered
What's the difference between trammel points and a compass?
A compass has a fixed, integral arm that limits its maximum radius to a few inches; trammel points are separate clamping heads that mount onto any beam, so the maximum radius is limited only by beam length, making them the standard tool for large-radius layout work that a compass physically can't reach.
Do I need scribe points or pencil points?
Scribe points have a hardened steel tip designed to cut a fine, visible line into metal for machine shop and fabrication layout. Pencil points hold a standard pencil or lead for marking wood, drywall, or paper templates. Using a pencil point on metal won't leave a durable or precise mark, and a scribe point will tear paper or soft material.
How accurate are trammel points for machine shop layout?
Machinist-grade trammel points with a graduated steel beam can hold radius settings within a few thousandths of an inch, comparable to other precision layout tools, provided the beam is rigid and the point clamps don't creep under use. General-purpose layout sets are less precise and best suited to woodworking or construction marking rather than tight-tolerance machine work.
What beam should I use with trammel points sold separately?
Any straight, rigid beam with enough length for your maximum radius will work — wood, aluminum bar, or steel rule are all common choices — as long as the trammel point clamps fit the beam's cross-section securely. A graduated steel rule beam is preferred when repeatable, measured radius settings matter.
Can trammel points scribe an ellipse, not just a circle?
Some trammel-based methods (the classic 'trammel of Archimedes') can generate an ellipse using two points sliding in perpendicular slots, but that requires a specialized elliptical trammel jig, not standard beam trammel points, which are built specifically for circular arcs and full circles.
Keep browsing
Related Categories
Explore More
Find Your Next Part Now.
Describe a part number, spec or what it does.