Guide · Measuring and buying
Measure your router table and router before buying parts
Five numbers decide most router table fits: plate outline, thickness, corner radius, miter slot and your router's exact model. How to record each, with a worksheet.
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Short answer
Five numbers decide most fits: the plate outline, the plate thickness, the corner radius, the miter slot's width and depth, and your router's exact model (which tells the lift maker its motor diameter). Record them before you shop, then compare each with the part maker's own figures.
Plate outline and thickness
Measure the plate you have, or the opening if the table has no plate yet: length, width and thickness. Do not assume a size. INCRA says its lifts and plates measure 9-1/4 x 11-3/4 in outside and 3/8 in thick, and that there is no industry-standard opening size.[1] INCRA also says openings in its own tables are about 0.020 in larger than the plate in each dimension; that figure is for INCRA tables only.[1] JessEm's Mast-R-Top is cut for a 9-1/4 x 11-3/4 x 3/8 in insert plate.[2] If your outline is closer to 8-1/4 in, read the plate sizes guide.
Corner radius
Corners differ from maker to maker. INCRA specifies a 0.750 in corner radius for its Mast-R-Lift II plate.[3] Kreg's plate instructions show 3/4 in radius corners for Kreg's own opening.[4] Neither is a standard. A radius gauge or a coin of known size held in the corner tells you whether yours is close; if it is not, ask the plate maker.
How the plate is supported
Look under the top. Kreg describes two ways to mount its plate: in a rabbeted opening, or in a straight-sided opening with its separately sold levelers.[4] INCRA says tables without a rabbeted ledge, such as Kreg and JessEm tables, need its CleanSweep Table Adapter to support its lift.[3] Measure the top's thickness too. Kreg says the screws supplied with its PRS3040 levelers are meant for tops at least 1 in thick.[5] Kreg lists its PRS1015 fence for tops 3/4 to 1-1/2 in thick.[6]
Inches and millimeters
Converting is arithmetic, not a tolerance. A nominal 9-1/4 x 11-3/4 in outline converts to 234.95 x 298.45 mm, and 8-1/4 in to 209.55 mm.[7] A nominal 3/8 in thickness is 9.525 mm, and a 4.2 in motor diameter is 106.68 mm.[7] Makers' metric labels may round differently, so compare like with like.
Your router's motor
Find the model plate on your router and write down the full model number. The lift maker's chart gives the diameter and clamp setting by model. JessEm's Mast-R-Lift II manual puts the Porter-Cable 7518 at setting A1 for a 4.2 in motor,[8] groups the Porter-Cable 690/890, Bosch 1617/1618 and DeWalt 610/618 at F4 for a 3.5 in motor,[8] and lists the Milwaukee 5615/5616/5619 at G3 with a 3.32 in diameter.[8] Those are JessEm's chart values for that lift. Do not measure the body and guess a clamp: use the model. The motor diameter guide collects the charts.
Unlisted router, blank plate
If no predrilled plate lists your router, a blank plate may. INCRA says its undrilled plate accommodates unlisted routers whose mounting fasteners sit fully outside a 2-1/16 in (53 mm) radius from the collet centerline.[9] That rule is INCRA's, for its plate. Follow the plate maker's own drilling instructions or template.
The miter slot
Measure the width at several points along the slot, then the depth, and check for a wider T-slot at the bottom. Bosch says the RA1181's slot works with most table saw miter gauges that measure 3/4 in wide x 3/8 in deep.[10] INCRA's checker gives a typical 3/4 in slot as 0.740 to 0.770 in actual width, at least 0.375 in deep, with an optional T-slot area 1/8 in high x 15/16 in wide.[11] INCRA states that its Miter 1000SE adjusts to actual widths of 0.740 to 0.765 in,[12] as does its Miter Slider SE.[13] Your reading has to fall inside the range of the gauge you buy. See the miter slot guide.
Your worksheet
Measure with your own tools and fill this in before you shop.
| What to record | Your reading | Compare with |
|---|---|---|
| Router make and full model (from its plate) | The lift or plate maker's list | |
| Plate or opening length x width | The part's stated outline | |
| Plate thickness | The part's stated thickness | |
| Corner radius | The part's stated radius, if any | |
| Ledge (rabbet) or levelers | The lift maker's support note | |
| Top thickness | Leveler screws and fence clamp range | |
| Ring system on your plate | The ring set's stated system | |
| Miter slot width (3 points) and depth; T-slot yes or no | The gauge maker's range | |
| Fence slot spacing or table width | The fence maker's range |
When the numbers fit nothing
Ask the part maker before you buy, with your router's model and these readings. A part that is not listed for your router or table is not confirmed, even if one number matches.
Parts that state their numbers
Picks that fit4 products
A 9-1/4 x 11-3/4 x 3/8 in opening and a Porter-Cable 690/890 or Bosch 1617: Kreg PRS4036, the predrilled version.
More on choosing
A router on Kreg's Pattern 1 or 2 list: Kreg PRS4038, the undrilled version. A measured 3/4 x 3/8 in slot: Kreg KMS7102 or POWERTEC 71391, after comparing your slot with the range each maker states. On Amazon, check that 'Ships from / Sold by' shows Amazon.com or the brand.
Predrilled for Porter-Cable 690/890 and Bosch 1617
Kreg PRS4036 Precision Router Table Insert Plate, predrilled for Porter-Cable and Bosch
Undrilled, with two marked patterns
Gauge with a long fence and swing stop
Gauge for slots with or without a T-slot
POWERTEC 71391 precision miter gauge system with 24 in multi-track fence and flip stop
Next
Questions
How do I measure my router table plate?
Measure the plate you have, or the opening if there is no plate: length, width and thickness, then the corner radius. Compare those with the part maker's stated figures. INCRA says there is no industry-standard opening size.[1]
How do I find my router's motor diameter?
Read the model number on your router's model plate, then look it up in the lift maker's chart. JessEm's Mast-R-Lift II manual, for example, lists the Porter-Cable 7518 at 4.2 in and the Milwaukee 5615/5616/5619 at 3.32 in. Do not guess a clamp size from a tape reading.[8]
How do I measure a miter slot?
Measure its width at several points along its length and its depth, and look for a wider T-slot at the bottom. INCRA's checker gives a typical 3/4 in slot as 0.740 to 0.770 in wide, at least 0.375 in deep. Compare your numbers with the gauge maker's stated range.[11]
My numbers don't match any maker's list. What now?
Ask the part maker before you buy, with your router's model and your measurements. A part that is not listed for your router or table is not confirmed to fit.