ian maybury
06-05-2015, 3:57 PM
The details of this DIY sub fence are fairly self evident, but it may perhaps be of interest to a few. It's not been used much yet, so there's no claims made regarding the safety or usefulness of the design. So far so good - but use your own discretion if heading down a similar road.
One downside of the stock Incra TS LS/rip fence is that it's quite high, and can't be flipped to a low setting like some. The height is essential in some situations, but less so when wanting to rip low and narrow pieces. The combination of the relatively wide connection to the modded dust hood on my Hammer K3 and the high Incra fence made access difficult - even with pushers. I also found myself thinking that there were times that a short/retractable fence that could safely be used as a cross cutting stop from behind the saw blade would be useful too - especially if it (as this does) read from the same datum/zero position every time on the Incra positioner.
The material is 3 x 3 x 1/4 in 6082 T6 square edged aluminium angle (a similar high strength grade to 6061 T6 in the US). The vertical flange was ripped down on the saw using a non ferrous blade, both edges were then smoothed using a car body file, engineering files and a progressively finer wet sanding block. The rounded corners prevent damage to work. There's a bit of filing technique in prepping the edges to avoid the various files scratching the surfaces - a few trial runs before touching the final item might be wise. The final polish used a steel wool pot scouring pad. Then natural anodised - essential as uncoated aluminium marks wood and wears quickly. There's a strip of UHMW/slick tape on the inboard (mounting side) full length along the bottom. The knobs are spare Incra 1/4-20 female with stainless socket head screws permanently fitted using high strength Loctite. T nuts in the slots in the Incra fence extrusion enable removal or re-positioning of the sub fence in a moment.
Check that the piece of aluminium angle is a good one before doing anything, they are often dinged, nicked, gouged and/or slightly bent. Straightness is dependent on not disturbing a fairly delicate balance of internal stresses in the metal. Anodising fortunately seems to present no problem, but heating is a no-no.
There are some important considerations. It's got to be accurately parallel within a thou or two viewed from above so that the toe out setting of the main fence is accurately replicated. The working edge must be dead smooth so that work slides easily along it. Think about how it will be used when retracted or pushed forward before deciding a length or drilling the holes for the mounting knobs. I set mine up so that it can be used as ether a Euro short fence terminating before the back edge of the blade, or pushed forward if needed - but bear in mind that my Incra fence is over length to the infeed end. (which gives great support on certain cuts, and allowed more freedom of layout) The extra hole at one end allows it to be hung up when not in use...
315094
One downside of the stock Incra TS LS/rip fence is that it's quite high, and can't be flipped to a low setting like some. The height is essential in some situations, but less so when wanting to rip low and narrow pieces. The combination of the relatively wide connection to the modded dust hood on my Hammer K3 and the high Incra fence made access difficult - even with pushers. I also found myself thinking that there were times that a short/retractable fence that could safely be used as a cross cutting stop from behind the saw blade would be useful too - especially if it (as this does) read from the same datum/zero position every time on the Incra positioner.
The material is 3 x 3 x 1/4 in 6082 T6 square edged aluminium angle (a similar high strength grade to 6061 T6 in the US). The vertical flange was ripped down on the saw using a non ferrous blade, both edges were then smoothed using a car body file, engineering files and a progressively finer wet sanding block. The rounded corners prevent damage to work. There's a bit of filing technique in prepping the edges to avoid the various files scratching the surfaces - a few trial runs before touching the final item might be wise. The final polish used a steel wool pot scouring pad. Then natural anodised - essential as uncoated aluminium marks wood and wears quickly. There's a strip of UHMW/slick tape on the inboard (mounting side) full length along the bottom. The knobs are spare Incra 1/4-20 female with stainless socket head screws permanently fitted using high strength Loctite. T nuts in the slots in the Incra fence extrusion enable removal or re-positioning of the sub fence in a moment.
Check that the piece of aluminium angle is a good one before doing anything, they are often dinged, nicked, gouged and/or slightly bent. Straightness is dependent on not disturbing a fairly delicate balance of internal stresses in the metal. Anodising fortunately seems to present no problem, but heating is a no-no.
There are some important considerations. It's got to be accurately parallel within a thou or two viewed from above so that the toe out setting of the main fence is accurately replicated. The working edge must be dead smooth so that work slides easily along it. Think about how it will be used when retracted or pushed forward before deciding a length or drilling the holes for the mounting knobs. I set mine up so that it can be used as ether a Euro short fence terminating before the back edge of the blade, or pushed forward if needed - but bear in mind that my Incra fence is over length to the infeed end. (which gives great support on certain cuts, and allowed more freedom of layout) The extra hole at one end allows it to be hung up when not in use...
315094