Technical - Workshop Notes
"Using a FENCE the correct way"
An unsupported job piece, is a common cause of a kickback.
This article attempts to outline ways that Members should consider how to use a FENCE, whether it be on a ROUTER table, a SAW BENCH or any STOP BLOCK approach.
It's not a matter of if a piece of wood will fly off the bench, but WHEN it will, and that can often be caused by either LACK OF SUPPORT, or incorrectly jambing a job between a fence and the blade.
Rotating machine saw blades and router bits have two impacts on a job. The rotating cutter either pushes the job down onto a support, or it tries to lift the job off, hurling it into the air. Support is needed, to hold a job down in place, whilst passing by the cutting blade/bit.
Trouble arrives, when trying to cut a job to an accurate size, by using a fence as the end-stop, and cutting the other end. So, let's investigate how this can be done correctly, in a number of machine scenarios.
1. TABLE SAW - bench top.
A table saw comprises a fixed saw blade, under a table top, with the cutting blade cutting towards the operator, who pushes a job into the blade, away from themselves, and out the far side. The initial cutting starts with a downward cut by the leading edge of the blade, pushing the job down into the bench, but as the job passes the back of the blade, which is rising up out of the table, then any lack of downward pressure (insufficient support), can allow the piece to lift off the table. KAOS!
Take a scenario where the FENCE is on the left side of the blade, and the distance between the fence, and the blade, represents the desired length of cut, whilst the remaining wood to the right of the saw blade is the offcut (regardless of size). Using a mitre slide, between the fence and the blade, with appropriate support (the wood held firmly to the mitre), can allow the job to pass right through and past the entire blade, taking care to stay clear of the spinning blade on the right of the operator's right arm/hand. Use a mitre or a sled, ensures the left end of the wood is supported (the piece being retained) so long as the job is held firmly against the mitre at all times, as well as applying downward pressure on the travel through.
By comparison, an incorrect method would be to push the job through with a mitre or sled on the right side of the blade, and not pushing all the way through. Any attempt to stop and lift out the desired end piece (on the left, cut to size), risks the pressure of the fence pushing the job against the spinning blade, to catch the piece and throw it to the air. (Kickback). With no real support on the piece, left of blade, it is at risk of catching, because it is not supported. It's the pressure between the blade and fence causing this, along with lack of any support to stop it flying.
A clever tactic, seen in this movie clip, is to put a spacer on the closest end of the FENCE (well before the cutting position is reached), for measuring/positioning the desired piece to be retained, hold firm on the mitre and push the job clear of the spacer well before the blade starts to cut. That way, the operator has the desired measurement to cut, but does not do any actually cutting whereby there is pressure or force between the rest of the fence and the rotating blade.
BEST SOLUTION: Use a SLED, that provides overall support of the job. A great example is one discussed by Phil Spencer in the JUNE 2013 edition of "Ingrained" at:
Bill Ireland has many too, well demonstratred in May 2019 edition of "Ingrained" on Page 9 at:
Thanks to Frank Collins, a real SLED affionado who showed his SLEDs in Sept 2019 "Ingrained" pg 6:
Gary Pope followed suit, with his attempt to make a SLED, outlined February 2020 "Ingrained pg 7:
2. SPIDA SAW - the ULTIMATE solution for docking lengths to size
A SPIDA saw, is the reverse of above table saw, as the saw blade hovers over the job, with the blade downwards, and the cutting pressure is pulling the job back towards the rear support of the bench. As the saw is pulled forward by the operator, the job is effectively forced down and backwards by the blade, where there is solid support. This is the 'go-to' machine for any docking of wood across the end-grain.
Cutting a piece to exact length is accomodated by using a tail stop, or a clamped block, up against which, the job is placed. True, in this scenario, the job is between the blade and a fence (be-it-all a STOP BLOCK). But due to the rotational force of the blade, pushing the job down and back against the rear wall, it is full supported. It is the SUPPORT aspect that ensures the job stays properly on the table. This is quite the opposite of the risks presented on a table saw.
3. COMPOUND SLIDING DROP SAW - (ie: pair of DeWalt units in the Sanding room)
These machines offer two basic cutting styles, irrespective of mitre angles or bevels being catered for.
(a) A straight vertical drop down technique, allows the operator to cut a thin piece of timber to size.
(b) But for wide planks, the technique is to pull the saw up and towards the operator first, then lower the blade into the close edge of the job (closest to the operator), and push the blade away to the far end. With the cutting teeth spinning into the job, the pressure of the blade pushes the job down and to the rear of the saw, against the rear support wall, thus ensuring the job is firmly supported during the cutting exercise.
The INCORRECT way to use the saw for wide planks is to drop the saw down and start cutting, followed by pulling the saw backwards towards the operator. That incorrect movement takes the pressure
away from keeping the job firm against the back support wall.
4. ROUTERS and use of the side fence.
For all outside routing of a job, an operator must stand at the right hand end of a router table, with the FENCE on the right hand side, containing the router bit spinning no more than 50% out from that fence. The picture below shows an ARROW indicating the direction that the job travels past the router bit. The job to be routed, is pushed away from the operator, past the left side of the router bit, which is spinning anti-clockwise. As the right side of the job is cut by the left side of the exposed router bit, the router is applying pressure on the job, towards the operator, who is pushing away from themselves against it, but holds the job down, and pushed away. Push sticks are the go here. The fence on the right, is acting as a straight guide to ensure a uniform router cut as the job is pushed all the way back, past the cutting bit.
*NEVER put the fence further right, and attempt to cut the outside of a job by passing the job in between the fence and the cutter. The anti-clockwise spinning router bit will pull the job right out of your hands and hurl it down the other end of the shed.
One exception: Routing the INSIDE of a job, like the inside edges of a photo frame or circular hole in the middle of a job. This is an INSIDE CUT. Here, the scenario is quite the reverse. The router bit is positioned far left of the fence, because the thickness of say, a picture frame, needs to pass between the router bit and the fence, whilst cutting the INSIDE of the frame. In this situation, the job needs to be placed slowly, but firmly down on the cutter, starting with a corner closest to the operator, and the job PULLED towards the operator, using the right side of the cutter, and leaning against the right-hand fence.
A STOP BLOCK at the far right end of the fence, is needed to ensure the starting cut point is where the operator drops the job down onto the cutter, without moving yet. A second stop block should be placed closest to the operator, aat a point representing where the cut will come to and end,, as the job is PULLED towards the operator to that stop block point. The job in cut by using a "PULLING CUT", between the two stop blocks, with pressure at all times to the right, against the fence on the right.
Take a rectangular photo frame, for instance. The first side to tackle would be the inside of the right side of the frame, cutting from the bottom right (inside) pulling the job down towards the operator, until the cutter reaches the top right corner of the job (of the inside cut). Repeat that four times, by stopping the machine and getting the next side to cut, placed again to cut a bottom right inside corner up to a top right corner, by pulling the job towards the operator. Note again, this INSIDE CUT procedure is the exact OPPOSITE of the best advice above for the more normal OUTSIDE cut process.