How to Adjust a Band Saw Upper Guide Height for Resawing
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Contents
Why Upper Guide Height Matters During Resawing
Resawing means cutting a board through its thickness to make thinner boards or veneers. Unlike ordinary ripping, the cut may be several inches tall, so the band saw blade is exposed to more sideways force. The upper guide assembly helps control that force, but only when it is set close to the work.
Set the upper guides as low as practical—normally about 1/8 inch above the board before the cut. This reduces the length of exposed blade, limits blade deflection, and improves safety. Raising the guides several inches above the stock may seem faster, but it gives the blade more room to twist and increases the chance of a wandering cut or broken blade.
Guide height is not the same as table height or fence height. You adjust the guide post or upper guide assembly so the thrust bearings and side guides stay close to the top surface of the board throughout the cut.
Prepare the Band Saw Before Adjusting
Disconnect power before placing your hands near the blade. Check that the blade is correctly tensioned, tracking near the center of the upper wheel, and suitable for the job. For most resawing, use a sharp blade roughly 1/2 to 3/4 inch wide with 2 to 4 teeth per inch. A wider blade tracks better, while a narrower blade may be easier to control on a smaller saw.
Make sure the table is locked and the blade is properly aligned with the fence. If the blade is dull, damaged, or incorrectly tensioned, changing guide height will not cure the problem. A dull blade often requires excessive feed pressure, which makes the blade bow away from the fence and can overload the guides.
If you are replacing the blade, a quality band saw resaw blade is usually a better investment than trying to compensate for a poor blade with tighter guide settings.
How to Adjust the Upper Guide Height
Raise or lower the guide post using the handwheel, rack-and-pinion control, or locking lever fitted to your machine. Move the assembly until the lowest part of the side guides and thrust bearing is approximately 1/8 inch above the highest point of the workpiece.
Use the actual board you intend to cut, not a thinner scrap. If the board is cupped, twisted, or has a raised corner, measure from the highest point that will pass under the guides. The guide clearance should remain small without touching the wood during normal feeding.
Lock the post firmly. Many band saws use a split clamp or locking knob, and a partially tightened clamp can allow the guide post to drop as vibration builds. After locking it, pull down lightly on the post to check for movement. Even 1/16 inch of unwanted movement can matter during a tall cut.
| Guide clearance | Best use | Likely result |
|---|---|---|
| About 1/8 inch | Normal resawing | Good blade control with enough clearance for the board |
| 1/4 to 1/2 inch | Uneven stock or rough setup | Acceptable, but more blade exposure and deflection |
| More than 1/2 inch | Generally avoid | Higher chance of wandering, vibration, and guide damage |
| Touching the work | Never use intentionally | Scoring, heat, stalled feed, or damaged guides |
Set the Side Guides and Thrust Bearing
Guide height alone is not enough. With the machine unplugged, position the side guides so they sit just behind the blade gullets. They should support the blade without squeezing its teeth or rubbing the tooth set. On many machines, the guides are set about 0.005 to 0.010 inch behind the blade body, roughly the thickness of ordinary paper or a thin business card.
Move the thrust bearing behind the blade with a similar small gap. It should not spin during free running, but it should contact the blade when feeding the board firmly into the cut. If the bearing is too far away, the blade can flex backward. If it is pressed against the blade continuously, it creates friction and heat.
After adjusting, rotate the wheels by hand and confirm that the blade does not strike the guides. Restore the guards, reconnect power, and run the saw briefly without stock. Stop immediately if you hear scraping, see excessive vibration, or notice the blade moving forward and backward in the guides.
Use the Correct Height During the Cut
Keep the guide assembly at the same height for the full cut whenever possible. Do not raise it midway to accommodate a thicker section unless you stop the machine, secure the stock, and reset the guides. On a long board, a high spot can catch the guide assembly if the clearance is too small, so flatten one face and one edge before resawing.
Feed the board steadily rather than forcing it. The proper feed rate depends on blade width, tooth pitch, motor power, and wood species. Hard maple, thick stock, and wet lumber usually require slower feeding than dry pine. If the blade begins to slow, pull the board back only if it can be done safely without twisting the stock. Do not push harder to recover speed.
A tall resaw fence or point-style fence can help maintain control, but it does not replace correct guide height. If you regularly cut boards 6 inches or taller, a band saw resaw fence may be worthwhile. For occasional resawing on narrow boards, the factory fence and a carefully adjusted guide post are often sufficient.
Troubleshoot Problems After Setup
If the cut wanders, first check the blade sharpness, tension, tracking, and fence alignment. A guide assembly set too high is one possible cause, but it is rarely the only one. A blade with too many teeth per inch can clog with sawdust and require excessive pressure. A blade that is too narrow may bend away from the fence on tall stock.
If the blade burns the wood, check for dull teeth, inadequate tooth clearance, excessive feed pressure, or guides rubbing the blade. If the blade breaks near the weld, inspect tension and alignment rather than simply lowering the guide post. Repeated breakage can also indicate a damaged wheel tire or a blade that has been kinked.
For occasional work, the cheaper option is fine: use the stock guide post, a sharp general-purpose resaw blade, and a stable fence. A taller aftermarket guide, upgraded thrust bearings, or ceramic guides make more sense when you resaw frequently, cut expensive hardwood, or need consistent veneer thickness. They cannot compensate for a twisted board, poor blade choice, or incorrect machine setup.
Final Safety Check
Before every resaw cut, verify that the guide post is locked, the guides clear the teeth, the thrust bearing is close behind the blade, and the blade guard covers as much exposed blade as practical. Keep both hands on the safe side of the blade and use a push device when your hands would approach the cutting zone. A 1/8-inch guide clearance is a useful target, but controlled feeding and a properly prepared board matter just as much.
