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Dead-Center Dowel Joints. Zero Clamps.

Cosari CenterLine Pro

Set the two steel pins across your board, twist until they touch both faces, and drill.

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  • ±0.02mm self-centering accuracy
  • HRC 58–62 hardened steel bushings
  • No clamps, one-hand operation
  • Fits 3/8" to 2-3/4" stock
Cosari CenterLine Pro
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Built Like a Machinist's Tool

Every part that touches the bit or the board is metal, machined to hold tolerance for years.

Twist-to-Center Geometry

Two steel pins close on opposite faces of the board as you rotate the jig, putting the bushing on the midline every time. No knobs to balance.

Hardened Steel Bushings

HRC 58–62 tool-steel bushings thread into the body, so the bit never touches aluminum. No wallowing, no chatter.

Solid 6061-T6 Aluminum

CNC-machined from one billet with Type-III matte red anodizing. 420 grams of rigid metal that can't rack or crack.

One Hand, No Clamps

The tapered arms give you leverage to hold the jig steady while you drill. Move to the next mark in seconds.

How the CenterLine Pro Works

Straddle and twist

Straddle and twist

Set the pins on either side of the board and rotate the jig. When both pins touch the faces, the bushing sits on the exact center.

Drill straight down

Drill straight down

Hold the arm with one hand and drill through the hardened bushing. It guides the bit at a true 90 degrees.

Join flush

Join flush

Glue in your dowels and bring the boards together. Centered holes mean the faces line up without sanding.

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Cosari CenterLine Pro

CNC-machined aluminum self-centering dowel jig with hardened steel bushings. Twist, drill, done.

Backed by our 30-Day Money-Back Trial & Full Cosari Guarantee.

$59.99 $119.99 Free Tracked Shipping (5–7 Days) Included

In Stock: Delivers in 5–7 Business Days. Free insured US delivery with tracking.

30-Day Money-Back Guarantee plus a full 2-Year Warranty.

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Description

Description: The Cosari CenterLine Pro is a self-centering doweling jig machined from solid 6061-T6 aluminum. Two steel locating pins straddle the board, and a simple twist centers the hardened steel bushing on the edge. It drills perpendicular dowel holes in stock from 3/8" to 2-3/4" thick, with no clamps and no measuring.

Materials & Build: CNC-machined 6061-T6 aluminum body with Type-III matte red anodizing. Hardened Cr12MoV tool-steel bushings (HRC 58–62). Dual 12mm steel locating pins with diamond-knurled thumbscrew caps.

Shipping & Returns: Free tracked shipping on every order. Covered by a 30-day money-back guarantee with no restocking fee.

5–7 Day Shipping & 30-Day Returns

Free 5–7 Day US Shipping: Every order ships free with full tracking and delivers in 5 to 7 business days.

30-Day Trial: Try it at home for 30 days risk-free. Need help? Email us anytime at support@buycosari.com.

2-Year Warranty: If anything goes wrong within 2 years, we replace it free of charge or refund your order in full.

Why Choose the Cosari CenterLine Pro?

Cosari CenterLine Pro Detail

Flush seams, less sanding

Centered dowels register both boards at the same height, so glue-ups come out flat.

Removable pins

Unscrew the knurled pins and the flat body becomes a 90-degree surface drill guide.

Three bit sizes

1/4", 5/16" and 3/8" bushings cover drawer boxes through workbench tops.

Cosari CenterLine Pro vs. Ordinary Alternatives

Cosari CenterLine ProStandard Competitors

FeatureCosari CenterLine ProStandard Competitors
Center the hole on the boardTwist until pins touch, doneMeasure, mark, balance two clamp screws
Hold position while drillingOne hand on the armF-clamp or C-clamp every hole
Guide bushing materialHardened HRC 58–62 steelBare aluminum, soft steel or plastic
Finished jointHidden dowels, flush facesOval pockets, plugs, possible lippage
Cost per jointA few cents in dowelsPocket screws plus plugs
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What's Included

In the Box
  • 1 × Cosari CenterLine Pro aluminum doweling jig with 2 knurled steel locating pins installed
  • 1 × 1/4" hardened steel drill guide bushing
  • 1 × 5/16" hardened steel drill guide bushing
  • 1 × 3/8" hardened steel drill guide bushing
Technical Specifications
  • Body: CNC-machined 6061-T6 aluminum
  • Finish: Type-III hard matte red anodizing
  • Centering accuracy: ±0.02mm (0.0008")
  • Bushings: Hardened Cr12MoV tool steel, HRC 58–62
  • Bushing sizes: 1/4", 5/16", 3/8" (approx. 6mm, 8mm, 10mm)
  • Locating pins: Dual 12mm steel with diamond-knurled thumbscrew caps
  • Stock thickness: 3/8" to 2-3/4" (10mm to 70mm)
  • Weight: 420 g
Care & Safety
  • Blow out chips and dust from the bushings after each session. A drop of light machine oil on the pin threads keeps the thumbscrews turning smoothly.
  • Wipe the anodized body with a dry cloth. Avoid harsh solvents, and store the jig on a hook or in a drawer so the bushing threads stay clean.
  • Backed by our 30-Day Money-Back Guarantee & Full Cosari Warranty
  • Customer Support: support@buycosari.com
In the Box Cosari CenterLine Pro

From Box to Flush Joint in 3 Steps

Swipe left for steps 2 and 3

  1. Place and twist
    1

    Place and twist

    Set the jig over the board's edge with a pin on each side. Twist until both pins touch and the scribe line meets your pencil mark.

  2. Drill
    2

    Drill

    Hold the arm with one hand and drill through the center bushing. No clamps needed.

  3. Dowel and join
    3

    Dowel and join

    Tap in glued dowels and press the mating board home for a flush, hidden joint.

Verified Customer Reviews

What 200+ Verified Buyers Say About the Cosari CenterLine Pro

Excellent Trustpilot
4.8
Based on 247 verified reviews
5 Stars
212
4 Stars
25
3 Stars
7
2 Stars
2
1 Star
1
97% of buyers recommend the Cosari CenterLine Pro
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Mark H.3 days ago

Passed the flip-board test on 4/4 hard maple

Tested this right out of the gate using the flip-board trick on 4/4 hard maple and couldn't catch a fingernail on the seam—dead center to the thousandth. No matter how tight I used to clamp my plastic pocket jig, the screw always pulled the joint 1/16" out of flush at the last turn. With this red aluminum jig, you just twist the two steel pins against the board edges and drill. Best shop upgrade I've bought all year.

Verified Purchase · Grand Rapids, MI · Cosari CenterLine Pro

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Dave R.6 days ago

48 holes in white oak in under 10 minutes

Drilled 48 dowel holes for a white oak tabletop glue-up in under 10 minutes using just one hand to pivot the tapered arm tight against the stock. Not having to mess with twin clamp screws saves me easily 20 minutes per panel. Plus wooden dowels cost pennies each and don't leave ugly pocket-screw craters underneath the tabletop.

Verified Purchase · Bend, OR · Cosari CenterLine Pro

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Greg S.1 week ago

Feels right on par with my $180 layout tools

My garage drawer is a graveyard of cheap stamped-steel and plastic dowel jigs that racked out of square after two projects. This solid CNC aluminum bar physically cannot rack. The bead-blasted matte red anodizing and knurled stainless thumbscrews feel right on par with my Woodpeckers layout squares at a fraction of the price.

Verified Purchase · lancaster, PA · Cosari CenterLine Pro

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Kenneth W.1 week ago

Zero drill chatter and zero bushing wear

I was skeptical at first that a brad-point bit might chew up the guide sleeves, so I ran over 120 holes through kiln-dried red oak for a bookcase build. The threaded hardened steel bushings have zero slop, don't chatter at entry, and still look untouched inside.

Verified Purchase · Austin, TX · Cosari CenterLine Pro

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Brian K.2 weeks ago

Bonus trick: unscrew the pins for 90-degree bench dog holes

Figured out a great bonus use in the shop—unscrewing the two cylindrical steel locating pins lets you lay the flat aluminum body right on top of a workbench slab to drill dead-plumb 90-degree holes anywhere in the middle of a panel. Zero plastic parts to crack in an unheated garage either.

Verified Purchase · Spokane, WA · Cosari CenterLine Pro

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Paul M.2 weeks ago

Laser center line hits pencil tick marks dead on

Why spend $170 on a fussy multi-rail contraption when simple lever geometry centers the guide bushing automatically in one twist? The laser-etched scribe line is crisp against walnut and cherry pencil marks, and even on narrow 3/4" poplar face frames the rounded center disc gives plenty of bearing surface so the drill never tips.

Verified Purchase · Raleigh, NC · Cosari CenterLine Pro

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steven_l3 weeks ago

Rock solid accuracy, just grab good stop collars

The jig itself is dead accurate and built like a tank. Only reason for 4 stars instead of 5 is I wish I had ordered two right away so I could leave different bushing sizes threaded in during cabinet builds. Make sure you use split-ring stop collars on your drill bits so you get repeatable depth to match the dead-on centering.

Verified Purchase · Columbus, OH · Cosari CenterLine Pro

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Arthur D.3 weeks ago

Retired my pocket-hole setup for face frames

Built six shaker vanity frames over the weekend and didn't have to sand a single stepped joint. Normally pocket screws creep just enough on maple stiles that I spend an hour hitting the joints with 80-grit. Every rail and stile slid together flush with light mallet taps.

Verified Purchase · Manchester, NH · Cosari CenterLine Pro

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Chris V.1 month ago

Heavy, grippy, and dead simple

No tiny hex wrenches to lose in the sawdust whenever you switch board thickness. Whether I grab rough-milled 7/8" stock or standard 3/4" plywood, pivoting the two silver pins centers the guide hole automatically. The knurling on the thumbscrew caps is sharp enough to tighten easily with dusty hands.

Verified Purchase · Fort Collins, CO · Cosari CenterLine Pro

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Tom B.1 month ago

Saved a walnut dining table glue-up

Edge-gluing eight-foot walnut boards without alignment biscuits or dowels is a nightmare once the Titebond makes them skate around. Popped a dowel every 14 inches with the TruAlign Pro and the whole panel clamped up flat enough that a few passes with a card scraper finished the seams.

Verified Purchase · Duluth, MN · Cosari CenterLine Pro

Stop Sanding Out Lippage. Start Drilling Dead Center.

$59.99 $119.99 Free Tracked Shipping (5–7 Days) Included

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Frequently Asked Questions

Are the guide holes lined with hardened steel, or does the bit cut the aluminum?

The bit runs through threaded hardened tool-steel bushings rated at HRC 58–62. The aluminum body never touches the bit, so the holes don't wear oval.

What drill bit sizes does it support?

It takes 1/4", 5/16" and 3/8" bushings (close to 6mm, 8mm and 10mm). All three bushings are included in the box.

What board thicknesses can it center on?

From 3/8" (10mm) drawer stock up to 2-3/4" (70mm) slabs.

How do I space holes along a long tabletop edge?

Mark your hole locations with a pencil, then line up the laser-etched scribe line on the jig's flank with each mark, twist to center, and drill.

Can I remove the locating pins?

Yes. The knurled thumbscrew caps unscrew by hand in a few seconds, and the flat body can then be used as a 90-degree drill guide on a surface.

Will the red finish rub off on light woods like maple?

No. It's a Type-III hard matte anodized finish, which is part of the metal surface rather than a paint, so it doesn't transfer or mark the wood.

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