Tri Scribes Multifunction Marking Tool

hand tools

drill bits

vacuum systems

How many different marking and cutting devices to you have lying around your shop? Aside from a coffee mug, cigar box, or drawer full of pencils, how many Xacto-type knives, marking and cutting knives, scribes and gauges, compasses of various sizes, etc., are cluttering up your bench, drawers, and every other nook and cranny that can hold such a device? And for all that clutter and wasted space, how many of them are really accurate enough to be worth keeping around? Sure, some of them are, but the few that are usually aren't versatile because their accuracy is at least in part dependent upon a rigidly limited design with a single task in mind. As is always the case when we spot this kind of scenario, we looked for relief and couldn't find it, so we created it, for our use and yours.

What's in a name? We call them "Tri Scribes" because we originally designed them to go with our three-dimensional try-square, which we jokingly dubbed our "tri-square" before naming it the M3, and kept the name after deciding to make them available for any flat-bladed rule and discovering a "bazillion" other uses for them. Simplicity itself, the Tri-Scribes set consists of a left and a right unit, each with a removable scribe post. Each unit has a large brass pinch bolt above a "C"-shaped mounting slot that enables you to lock the unit in position on any standard steel or rule. The units have angled necks with a smaller brass pinch bolt on the side that holds a scribe post, a pencil or a Tri-Blade cutting post securely at the required depth. The angle of the neck unit provides optimum contact and alignment between scribe point and the surface of the workpiece.

Ready for some magic? Not necessary when good old-fashioned physics can be made to work in your favor. The flat-lying base plate is angled to transfer the weight of the unit forward onto the scribe point, pencil or blade, making their tip the primary load point and keeping the blade upon which they ride flat and more rigid than traditional trammel points, providing a much-needed level of stability, even when drawing long arcs, that you will find delightful.

Stock Fence Contact and Stability

Have you ever considered the geometry of a marking gauge or cabinet maker's scribe? It's no wonder they are so unstable. Think of the fence as a "tic-tac-toe" board, divided into nine roughly equal areas. The post comes out of the middle square, and the workpiece rides along the bottom three squares. Hence, only 1/3 or less of the surface contact area of traditional marking gauge fences is actually touching the workpiece. The depth-range to fence-width ratio is also poor. Ordinarily the rule of thumb here is your fence-width should have at least 1/1 ratio with the depth-range. Beyond that range the fence-width does not provide enough guaranteed stability for precision accuracy. At 2¼" fence-width most marking gauges will be prone to wobbling at just over 2¼" deep, and that's if you're working a material that is perfectly consistent in texture, which by its very nature, wood is not.

Also note that a marking gauge is configured as a lever, with both the fence and scribe point as potential fulcrums. As long as the fence is the fulcrum, everything is fairly smooth, but if the scribe point digs in enough to become the fulcrum, a series of disastrous events ensue where the force oscillates between sheer (pushing or pulling in line with the mark, with the fence as the fulcrum) and moment (pushing or pulling in an arc, at odds with the line, with the scribe point as the fulcrum) until forces regain balance or you react reflexively and stop the cut. What a mess!

By attaching the Tri Scribe unit to a try-square or combination square you increase the fence-width and also the contact area with the workpiece, and you guarantee that the force applied will be parallel to the desired mark. This makes marking more stable, precise and easier for you to do accurately.

Trammel Bar Compass vs. Flat Lying Compass

Let's compare. Have you ever tried to draw an arc or circle with a radius nearly as long as your reach with trammel points? Due to the vertical orientation of traditional trammel points, while marking or scribing an arc or circle they must be held perpendicular (90-degrees) the workpiece at all times to ensure accuracy and precision, and if the blade to which you've secured them flexes a bit, your arc or circle is no longer true, and if the blade lays over (such as when you're off-balance from having over-extended your reach) you may get a wild mark or no mark at all as the blade flexes and the focal trammel point slips out of its hole. Unless you have really long arms and a super-rigid rule, it's usually tedious, aggravating, and inaccurate.

Can you see where laying the rule's blade flat to the table top would solidify both the length and position of the marking apparatus? M.POWER's Tri-Scribes have been designed to lay flat on the workpiece, making them inherently stable, consequently giving you much more precise and consistently accurate marking of arcs and circles.

Large and Small Circle Marking

How big or small do you need to go? Tri-Scribes attach to any standard steel or aluminum rule; hence, the size of the radius you can mark is only limited by the length of your rule. Simply lock one scribe unit in place, measure out the required radius between the scribe point and pencil point and lock the second scribe unit.

Marking Gauge

We all like marking gauges until they slip in soft grain or spalting or stick in a knot and make a wild mark, at which point we realize that it's not the gauge we like, it's only our expectation of the gauge.(Sounds like dating, doesn't it?) The problem with standard marking gauges is that you apply force perpendicular to the pivot point created by the gauges scribe, which is supported by nothing but the resistance of the wood to the scribe point, so if the point buries and sticks, your hand has a tendency to keep moving. Simply put, they wobble, are difficult to master, and don't make woodworking easy or fun because the leverage is all wrong and the scribe point is unsupported, so a material flaw or an untimely sneeze can quickly make a mess of your workpiece. Adding a Tri-Scribe unit to a standard try-square or combination square transforms it into a very accurate and stable marking gauge because the forces in the marking unit are now parallel instead of perpendicular. Since the Tri Scribe will hold your choice of a scribe, pencil or blade, it is a both a marking and cutting tool, versatile, accurate, and simple to use.

Mortise Gauge

Need two parallel lines? Precision in joinery is key so why not use a tool you know will give you the most precise results? Attach both Tri Scribes to your try-square or combination square as a mortise gauge. Again the strengths of the Tri Scribes over a traditional gauge hold true, offering increased stability, accuracy and ease.

Panel Gauge

Do you use much sheet stock? These days it's difficult to avoid, because the materials are of such good quality and being able to design a table or panel without having to leave slop in your design to allow for wood movement is just too good a prospect to pass up most of the time. Most traditional marking gauges have a limited maximum range (6"-7" / 150mm-180mm) which means you must also have a panel gauge should you need to do any deep-range marking. Aside from the tendency of panel gauges to have all the weaknesses of a marking gauge amplified in their larger size, this is an additional cost and tool to store in the workshop or carry on site. By attaching the Tri-Scribes to a longer blade try-square or combination square you can mark panels with the same accuracy and ease that you mark mortises, tenons, rabbets, etc., and you don't have to buy, store or carry an extra tool to do so.

Cutting Gauge

Do you sometimes need, or simply prefer, a blade instead of a scribe? We've got you covered there, too. The addition of the Tri-Blade post to the Tri Scribe creates a cutting gauge that can cut parallel lines and circles. Add one to each Tri Scribe for Japanese-style mortise marking with a knife. Ideal for trimming veneers and cards precisely, the Tri-Blade also allows very fine and accurate marking lines to be cut. This ability can be very useful when marking across the grain where a precise cut is more appropriate than a torn scribing line.

The versatility, accuracy, and ease of use of the Tri-Scribe and Tri-Blades are truly marvelous. Clear out the clutter and drop a set in your tool box right now. Buy one now from a supplier near you!