How to Build a Jointer Infeed Support for Long Lumber
What's inside
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A jointer can flatten a board beautifully, but long lumber creates a leverage problem. As the board leaves the infeed table, its weight can pull the leading end downward. That changes the cut, makes the board harder to control, and can produce a tapered or uneven face. An infeed support keeps the incoming board level with the jointer table so you can maintain steady pressure without wrestling the stock.
Contents
What the Support Needs to Do
A useful infeed support must be level, rigid, and adjustable. It should carry the board before it reaches the jointer without lifting the board above the cutterhead. The support also needs enough width to prevent a narrow board from tipping sideways.
For most 6-inch to 8-inch jointers, a support surface 18 to 24 inches wide and 30 to 48 inches long is practical. The exact length depends on your shop and the lumber you normally handle. A longer support helps with 8-foot boards, but it takes more floor space and is more likely to sag unless it has a solid frame.
Measure the jointer’s infeed table height from the floor, not from a nearby bench. Check this measurement with the cutter guard in its normal position. The top of the support should finish approximately 1/32 inch below the jointer table. Slightly low is safer than high; a high support can lift the board into an inconsistent cut or interfere with the cutterhead.
Materials and Hardware
The least expensive version uses a plywood top on a folding work stand. A 3/4-inch plywood panel is adequate for a support up to about 24 inches wide. If the support is longer than 36 inches, add a pair of 2×4 rails underneath or use a torsion-box construction to prevent sag.
For a top that rolls easily, install several low-profile ball-bearing rollers. A smooth plywood surface is cheaper and works well for dusty stock, but rollers reduce pushing effort on heavy oak, maple, and construction lumber. Look for woodworking ball-bearing rollers with a load rating comfortably above the boards you handle.
| Support type | Best use | Advantages | Limitations |
|---|---|---|---|
| Plywood platform | Occasional use and lighter boards | Cheap, stable, easy to build | More friction; can swell if it gets wet |
| Ball-bearing rollers | Long or heavy lumber | Low pushing force and smooth feeding | Need accurate height adjustment; debris can affect rollers |
| Folding roller stand | Small shops and temporary setup | Stores easily and is widely available | Can shift or rock under side pressure |
| Fixed cabinet support | Frequent jointer use | Most rigid and stable | Takes floor space and costs more to build |
You will also need two adjustable mounting points, four carriage bolts or knobs, washers, and locking nuts. Threaded inserts or T-nuts make height adjustment easier if the support is removed regularly. A pair of adjustable machine leveling feet can stabilize the frame, but ordinary threaded bolts with jam nuts work just as well.
Building the Platform
Cut the plywood top to the size you need and ease the front corners and edges with a router or sanding block. Sharp corners catch clothing and can snag the edge of a board. If using rollers, mount them in two or three rows with their axles perpendicular to the feed direction. Keep the roller tops in the same plane; a roller that sits even 1/16 inch high can lift the board and change the cut.
Build the frame from straight 2x4s or hardwood. Use one crossmember near each end and at least one in the middle. For a 48-inch support, the middle crossmember is important. Without it, a heavy board can deflect the plywood enough to make the support effectively low in the center.
Attach the platform to a folding stand, a pair of sturdy sawhorses, or a dedicated frame. A folding stand is fine when the jointer is used occasionally, but add non-slip pads and clamp the stand to the jointer if possible. The support must not roll away as you push a board across it.
Making Height Adjustment
The simplest adjustment uses slotted mounting holes. Cut 1/4-inch-wide slots vertically in two mounting brackets, allowing at least 1 inch of adjustment. Bolt the brackets loosely, set the support height, then tighten the hardware. Use large washers so the bolts do not pull through the slots.
A more precise option uses threaded leveling feet under the frame. Put one adjuster near each corner, then use a straightedge spanning the support and jointer table. Raise or lower the support until the straightedge passes smoothly across the joint with no visible step.
Test with the longest and heaviest board you expect to joint. Place the board on the support and check again. The weight can flex both the support and the stand. If the infeed end drops more than about 1/32 inch under load, add a brace or raise the outer end slightly. Do not compensate by making the whole support high.
Using the Support Safely
Before starting the jointer, confirm that the support cannot contact the cutter guard, cutterhead, or fence. Keep the support below the table and leave enough clearance to operate the jointer’s controls. Never reach over the cutterhead to correct a board that has shifted.
Support the board near its leading end as it approaches the cutter, then move your hands onto the jointer table according to the machine’s normal feeding procedure. Keep downward pressure over the infeed table until enough stock has passed to transfer pressure to the outfeed table. The support is there to reduce leverage, not to replace proper hand placement or push blocks.
Inspect the setup whenever you change board thickness. A support adjusted for a 1-inch board may be wrong for a 2-inch slab, particularly if the rollers are fixed-height. For occasional work, a plywood platform on a solid stand is the sensible cheaper option. If you regularly joint long hardwood, the extra cost of adjustable rollers and a braced frame pays off in steadier feeding and fewer damaged boards. A ready-made heavy-duty woodworking roller stand can also be a reasonable shortcut, provided it locks securely and adjusts low enough to match your jointer.
