This is a pretty nifty tool to keep on hand! 

 

Grab the Drillpro 200/300/400mm Stainless Steel Precision Marking T Ruler from Banggood for just $17.99 -- normally $28.00!

 

Description:
Drillpro 200/300/400mm Stainless Steel Precision Marking T Ruler Hole Positioning Measuring Ruler Woodworking Scriber Scribing Tool
- Independent and innovative design, specially designed for positioning and marking of woodworking tennon and mortise, convenient and precision.
- Horizontal line, vertical line, long line, short line, parallel, right angle, let the scribing do whatever you want, satisfy all the scribing needs.
- Fine marking holes and slots at every 1mm, 0.5mm, 0.25mm scale position, make the operation accurate.
- Combination square for marking with perfect, instant accuracy.

Specification:
Material: Stainless Steel
Color: Silver
Size: 200/300/400mm
Hole diameter: 0.5mm
Fit for refill: 0.5mm
Every hole and slot distance: 1mm, 0.5mm and 0.25mm

Features:
1. Made of stainless steel, the scale is clear and accurate, CNC machining, comfortable texture.
2. Vertical knurled nut is made of pure copper.
3. Precise, versatile, and easy to use.
4. Let the scribing do whatever you want, satisfy all the woodworking scribing needs.
5. Provides you 200/300/400mm size for choosing.
6. Locate your sharp 0.5mm pencil or scribe with absolute precision

Package Included:
200mm A:
1 x 200mm Marking T Ruler
1 x Pencil
1(set) x Refill

200mm B:
1 x 200mm Marking T Ruler

300mm A:
1 x 300mm Marking T Ruler
1 x Pencil
1(set) x Refill

300mm B:
1 x 300mm Marking T Ruler

400mm A:
1 x 400mm Marking T Ruler
1 x Pencil
1(set) x Refill

400mm B:
1 x 400mm Marking T Ruler