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Why do welding tables have holes? Welding tables have holes so you can lock clamps, stops and squares into a fixed grid and hold your parts in the same spot every time. The holes turn a flat steel top into a modular fixture system.
On a plain top, you clamp to the edge and hope the part stays put. On a holed top, you drop a stop into any bore, push the part against it and clamp it down in seconds.
We cover what the holes do, the common sizes from 16 mm to 28 mm, the grid patterns, and how to choose a system for your shop.
Why Do Welding Tables Have Holes: The Short Answer
Welding tables have holes to give clamps, bolts and stops a fixed, repeatable place to lock in. That lets you square, hold and repeat a setup without tack welding jigs to the top.
Strong Hand Tools, writing in The Fabricator, sums up the main benefits of modular fixturing as adaptability and repeatability. Here is what that means at the bench:
- Clamp anywhere: a clamp can go into any bore on the top, so you are not limited to the table edge.
- Fast square setups: 2 stops in the holes form a fixed right angle. Push both parts against them and check square before you tack.
- Repeat parts: the same hole positions give the same part every time, which helps on batch work and one-off jobs alike.
- Less distortion: parts clamped down hard move less as the weld cools.
- 3D setups: many fixture tables have holes in the side walls too, so you can build fixtures off the edge and up from the top.
What Goes Into the Holes
The holes are only half of the system. The other half is the tooling that locks into them.
- Clamping bolts: they hold stops and squares tight to the top. Siegmund sells its bolts in 5 different designs.
- Stops and fence blocks: fixed edges to push parts against. Fireball lists a 100 x 50 x 25 mm fence block for its FM19 tables.
- Fixture clamps: Strong Hand FixturePoint clamps and components insert straight into the 16 mm holes on its tabletops.
- Squares and angles: bolt-on corners for 90 degree and angled frames.
- Spacers and shims: they lift the work off the top so less heat goes into the table.
Common Welding Table Hole Sizes and Grid Patterns
Most fixture tables are sold by bore size. Siegmund puts it simply: the system is defined by the borehole size. These are the published specs from the makers we checked.
| System | Hole diameter | Grid | Top thickness | Maker’s intended use |
|---|---|---|---|---|
| Strong Hand FixturePoint (36 x 24 in) | 16 mm (0.63 in) | 2 x 2 in | 0.16 in | Light work, 500 lb static load |
| Siegmund System 16 | 16 mm (0.63 in) | 50 mm (about 2 in) | 11.5 to 13 mm | Light to medium work, precision fixtures |
| Fireball FM19 | 19 mm (0.75 in) | 50 mm (about 2 in) | 12 mm or 25 mm, cast iron | Standard Duty and Heavy Duty tables |
| Siegmund System 22 | 22 mm (0.87 in) | 100 mm or diagonal | 17 to 19 mm | General metalwork, moderate distortion |
| Siegmund System 28 | 28 mm (1.10 in) | 100 mm or diagonal | 24.5 to 27 mm | Multi-ton parts, high distortion forces |
Siegmund rates its System 28 tables for loads up to 6,000 kg (about 13,228 lb), System 22 up to 3,000 kg and System 16 up to 2,000 kg. Those figures are Siegmund’s recommended loads, so check the rating on the exact table you buy.
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How Hole Size and Grid Change What the Table Can Do
Siegmund says to pick a bore size by the weight of your parts and the distortion forces you expect. Bigger bores take bigger bolts, and those bigger bolts resist more pull from a cooling weld.
16 mm Holes
The 16 mm size fits small shops, light frames and precision fixtures. Siegmund pairs it with a 50 mm grid, which gives you twice as many clamping spots as a 100 mm grid.
22 mm Holes
Siegmund calls System 22 its all-rounder for general metalwork. It uses a 100 mm grid or a diagonal grid on a thicker top than System 16.
28 mm Holes
The 28 mm size is the heavy-duty choice for structural work and big weldments. It uses heavy-duty bolts on a top close to 1 inch thick.
Square vs Diagonal Grids
A square grid puts holes in straight rows. Siegmund’s diagonal grid adds holes between them, which doubles the clamping options for parts set at an angle.
Fireball takes a middle path with 19 mm holes on a 50 mm grid. Fireball says that layout gives 2 times the holes of a 28 mm table.
Tool Compatibility Between Brands
Bore diameter decides which tools fit. Strong Hand Tools says its BP16 tools fit any welding table with 16 mm boreholes from any maker.
There are exceptions. Strong Hand also says its BP16 tools do not fit its own FixturePoint tables, which use a separate clamp line.
Watch the inch sizes too. A 5/8 inch hole is about 15.9 mm, close to 16 mm, but Strong Hand sells 5/8 inch and 16 mm tools as separate systems. Check the fit chart before you mix them.
Holes, Spatter and Table Life
Holes do not make a fixture table weak. The load ratings in the specs show holed tops carrying several tons when the plate is thick enough.
Spatter is the bigger day-to-day issue. Fireball says its gray cast iron top resists spatter and does not form burrs. Steel tops can take spatter on the surface and in the bore edges, so keep the holes clean or tools will not seat flat.
Strong Hand also suggests raising the work on spacers. That cuts the heat going into the tabletop and helps the top last longer.
When a Holed Fixture Table Makes Sense
A fixture table pays off when you build frames, brackets, gates or anything that has to come out square. The Fabricator piece lists prototyping, one-off jobs, high-mix work and repeat production as good fits.
For the odd repair weld, a solid steel top and a few C-clamps can be enough. Many home welders also drill a hole grid into a thick plate to get some of the same benefit.
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Tips for Using a Welding Table With Holes
- Buy tools for your exact bore size, not the closest one.
- Set 2 stops first, then check square before you tack.
- Clamp the part down after it touches the stops. A stop alone will not hold it.
- Lift the work on spacers to keep heat out of the top.
- Clean spatter out of the bores so bolts seat flat.
- Start with a small kit of stops, squares and clamps, then add parts as jobs need them.
Safety note: parts and fixtures stay hot long after the arc stops, so wear welding gloves when you move clamps. Large steel and cast iron tops weigh hundreds of pounds, so move them with a lift or a helper.
Frequently Asked Questions
What Size Are the Holes in a Welding Table?
Most fixture tables use 16 mm, 22 mm or 28 mm bores, and Fireball uses 19 mm. Siegmund sells all three metric sizes. The 16 mm size suits light and medium work, and 28 mm suits heavy parts with high distortion forces. Buy clamps and stops that match your bore.
Are 16 mm and 5/8 Inch Welding Table Tools the Same?
They are close but not identical. A 5/8 inch hole measures about 15.9 mm, and Strong Hand Tools sells its 5/8 inch and 16 mm tools as separate systems. Check the maker’s fit chart before you mix pins, bolts or clamps between the two sizes on your table.
What Is the Hole Spacing on a Welding Table?
Siegmund lists a 50 mm grid for System 16 and a 100 mm grid for Systems 22 and 28, with a diagonal grid as an option. Strong Hand FixturePoint tables use a 2 inch grid. A tighter grid gives you more spots to place a stop or clamp.
Can You Drill Holes in Your Own Welding Table?
Yes, many home welders drill a grid into a thick steel plate. The result is only as good as your hole spacing and diameter. Use a drill press or mag drill, mark the grid carefully, and size the holes for the clamps you plan to buy.
Is a 16 mm or 28 mm Welding Table Better?
Neither size wins for every shop. Siegmund rates its System 16 for light to medium work and precision fixtures, and its System 28 for heavy, multi-ton structures. Pick by the weight of your parts and how hard the welds pull on them as they cool.
Final Words
Welding tables have holes so clamps, stops and squares can lock into a fixed grid. That gives you faster setups, square parts and the same result on every repeat.
Pick 16 mm for light and precision work, 22 mm for general fabrication and 28 mm for heavy structures. Then buy tools that match your exact bore, and keep those holes clean.
