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How to use a dowel jig so the joint actually closes

Updated: 22 October 2026

You have an 18 mm shelf, a drill, and a jig that will put the holes in the wrong place if the depth is wrong or the gauge moves. This is how to use a dowel jig so the pin does not bottom out and the two faces meet. The sequence that fails least often is: set the depth, drill one side, transfer the pattern, clamp whatever the reviews say will wander, then dry-fit before glue. Which jig to buy is on the [dowel jig comparison](/hub/screws-and-accessories/dowel-jig) and the [dowel jig buying guide](/hub/screws-and-accessories/dowel-jig/sub/dowel-jig-buying-guide). The worked depths below are Wolfcraft’s, for their gauge, not a British Standard.

You have an 18 mm shelf, a drill, and a jig that will put the holes in the wrong place if the depth is wrong or the gauge moves. This is how to use a dowel jig so the pin does not bottom out and the two faces meet.

Our top picks

Wolfcraft Wolfcraft Dowelmaster 4640000

Best overall

Wolfcraft Wolfcraft Dowelmaster 4640000
8.6/10about £12.96
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Wolfcraft Wolfcraft Dowelmaster set 4645000

Best value

Wolfcraft Wolfcraft Dowelmaster set 4645000
7.8/10about £28.30
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Idong Idong 3-in-1, 6/8/10/15 mm

Alternative

Idong Idong 3-in-1, 6/8/10/15 mm
6.8/10about £31.99
View offer
On this page
  1. 1.Set depth before the first hole
  2. 2.Drill one side and transfer
  3. 3.Hold the jig still
  4. 4.If it will not close

Set depth before the first hole

A centred hole still fails if the dowel is longer than the two holes. For a corner or T joint in 18 mm board with a 40 mm dowel, Wolfcraft puts at most 12 mm in the face, and 30 mm in the end: 28 mm of dowel plus 2 mm of glue space. Stay at or under two thirds of the thickness so you do not break the show face. For an edge-to-edge joint the same page says about half the dowel plus about 2 mm a side, so a 40 mm pin wants about 22 mm each way. Prove the collar in scrap. On the Idong block, UK reviews say the collars loosen.

Drill one side and transfer

Use the same reference face on both boards. Drill the first holes, then transfer. Measuring both halves with a tape is how a 2 mm error becomes a gap. Wolfcraft’s sequence glues the dowels into the first piece, then sets the guide slot on those dowels. The 4645000 set also includes six centre points, so you can mark the second board while the joint is still dry. Use the dry mark on a piece you cannot scrap. On the GQGP 8/10/15 mm listing, UK reviewers say the 10 mm bit has no collar. If the bush is missing, stop.
Wolfcraft Wolfcraft Dowelmaster 4640000

Testsieger

Wolfcraft Wolfcraft Dowelmaster 4640000
8.6/10about £12.96
View offer

Hold the jig still

UK reviews say the Dowelmaster moves while the bit is in the wood. A UK Workshop note says a handheld Wolfcraft vibrates and the collars slip on 18 mm MDF. That is a forum note, not a test of your parcel. Clamp the gauge before the drill starts, and keep your fingers off the bush. NIYATA’s reviews say you reposition the block for every hole. Idong’s reviews prefer the clamp, better on an edge than on a face. On MDF and chipboard, do not sweep the dust. HSE’s hardwood limit at work is 3 mg/m³. Use extraction, or a mask at APF 20 such as FFP3.

If it will not close

Dry-fit before any glue. If a pin needs a hammer, the hole is tight or the dowel is swollen, and forcing it splits chipboard. A plain pin in a tight hole can hold the joint open. If the dry fit gaps, the dowel has bottomed out, the second board was measured instead of transferred, or the hole is not square. Wonkee Donkee, a UK tool guide, says an off-square hole needs redrilling, not more clamp pressure. If the first dowels are already glued, you cannot move them. A chair, a stair or a bed rail is where you get a joiner. The clamp-versus-gauge difference is on the self-centring dowel jig page.

Common questions

What order do I drill?
Set the depth collar on scrap first, then drill one board, then transfer that pattern with a centre point or with Wolfcraft’s guide slot. Drill the mating holes only after the mark is there. Glue is last, after a dry fit closes with hand pressure. Measuring both boards from a tape, then hoping, is the order that opens a gap.
How deep for 18 mm board and a 40 mm dowel?
Wolfcraft’s example for a corner or T joint is 12 mm in the face and 30 mm in the end. The 30 mm is 28 mm of dowel plus 2 mm for glue, and the face hole stays at or under two thirds of the 18 mm thickness. For an edge-to-edge joint the same source says about half the dowel plus about 2 mm each side. Copy those figures only when your pin is 40 mm and your board is 18 mm. Then prove them in scrap.
Do I glue the first dowels before the second holes?
Wolfcraft’s Dowelmaster text does. You glue the dowels into the first piece, then locate the guide slot on those dowels to drill the mate. That is their sequence. Centre points, which are in the 4645000 box, let you mark the second board while everything is still dry. On a piece you cannot afford to scrap, the dry mark is the more forgiving of the two.
Why will the joint not close?
The usual causes are a dowel that has hit the bottom of a short hole, two patterns that were measured separately, or a hole that is not square to the face. Clamp pressure will bend a thin board and still leave the glue line open. Dry-fit, find which of those three it is, and redrill in scrap rather than on the show face. A tight pin that needs a hammer is a split waiting in chipboard.
When do I stop and get a joiner?
Stop when the joint is a chair, a stair or a bed rail, or any other joint that can injure someone if it fails. Stop when the show face is already broken through, and when a fitted cabinet has to hit existing 32 mm hardware. A first shelf in 18 mm board is still a DIY job if the dry fit closes. A joint you are being paid to install, in dust you are not controlling, is not.

Related pages

Dowel jig vs pocket hole

Dowel jig

Best dowel jig: one gauge, and the set that fills the box

Dowel jig buying guide: match the board before the brand

Self-centring dowel jig: jaws, pins, and a false mark

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are the amazon.co.uk listings stored for this comparison. HSE wood-dust limits apply as workplace exposure figures. They are not a certificate for a domestic jig.

  1. Wolfcraft Dowelmaster (retrieved 22 October 2026)
  2. Wolfcraft universal dowel set (retrieved 22 October 2026)
  3. HSE wood dust (retrieved 22 October 2026)
  4. HSE WD0, wood dust (retrieved 22 October 2026)
  5. HSE cutting and sanding wood (retrieved 22 October 2026)
  6. Consumer Rights Act 2015, section 22 (retrieved 22 October 2026)
  7. UK Workshop, dowel jig thread (retrieved 22 October 2026)
  8. amazon.co.uk, Wolfcraft Dowelmaster 4640000 (retrieved 22 October 2026)