Thread: MDF shooting boards ruins your planes

ok that makes sense in your ramped version what is the height dimensions of the ramp as I'm trying to replicate this.

The "height" of the ramp depends on how big you want to build your shooting board. What you want to do is build it around a ramp angle of 5 degrees.

Regards from Perth

Derek

The length of the board is 17 3/4" this is based off the LN drawings without the left wing.

If MDF has some metal in it as suggested, the SawStop manufacturer may have to add this material to the list of stuff you shouldn't feed into a SawStop table saw.

My men's shed took delivery of a SawStop saw, there is a list of stuff you shouldn't push through the system.

Wet wood (substantially wet that is, not dripping wet) conductive metal (timber with steel nails or screws embedded) etcetera.

Mick.

Originally Posted by Optimark

If MDF has some metal in it as suggested, the SawStop manufacturer may have to add this material to the list of stuff you shouldn't feed into a SawStop table saw.

My men's shed took delivery of a SawStop saw, there is a list of stuff you shouldn't push through the system.

Wet wood (substantially wet that is, not dripping wet) conductive metal (timber with steel nails or screws embedded) etcetera.

Mick.

I doubt there's enough metal in it to trip the sensor.

ElanJacobs, you may be right, but I wouldn't lay money on it.

At the last Melbourne Woodworking show, I watched at least 6 demonstrations of the SawStop unit doing it's stuff with a sausage sitting atop a piece of timber as the sacrificial human finger.

In one instance the sausage was not 90º to the saw blade, instead it was angled a fair bit to make the contact area quite small. The resulting damage to the sausage was contained to the sausage skin only, no internal sausage meat was touched.

This was, and considering that the timber was pushed into the saw blade quite fast, extremely indicative of how small a contact is required to set the defense mechanism off.

The damage inflicted to the sausage was about 1mm wide, by the depth of the sausage skin in this instance. There was no groove in the sausage meat from the corner of the blade tooth, a most impressive demonstration.

The various sausage damage from all of the demonstrations I witnessed, was incredibly small. Mostly the damage was approximately the width of the saw blade teeth, or a small fraction wider, by about 0.5 mm deep into the sausage meat.

Mick.

I've also seen the demos. A sausage is wet and has a high salt content and, therefore, will conduct very well - which is the whole point of the exercise. MDF is a) very low in moisture and b) essentially made of dust, so any metal in it is going to be so small that it will not be physically capable of conducting a meaningful amount of electricity.

Also, I can't imagine that SawStop would make something that can't be used with what is one of the most commonly used wood based construction materials in the world.

Originally Posted by DSEL74

If you do a google search you will find that MDF wheels are sold to grind/hone your tools to a nice sharp edge.

Yep, I use it to sharpen my blades with diamond paste and a very nice job it does I must say to the point I'm not going to change my method after trying the rest.

SB

Originally Posted by elanjacobs

I've also seen the demos. A sausage is wet and has a high salt content and, therefore, will conduct very well - which is the whole point of the exercise. MDF is a) very low in moisture and b) essentially made of dust, so any metal in it is going to be so small that it will not be physically capable of conducting a meaningful amount of electricity.

Also, I can't imagine that SawStop would make something that can't be used with what is one of the most commonly used wood based construction materials in the world.

I know this is getting a bit OtheT, but I've seen two online videos regarding the SawStop (even though it makes me a little ill - valuing fingers over fine machinery ) Matt VanDerList in particular, who gave a review after using it for 8 months or so.

The sausage only triggers the SawStop because a person is touching it. If you taped a sausage on top of some plywood and cut it wouldn't stop - unless sausage spray then came into effect. I'm sure he shows that. But also the SawStop has a procedure for starting it with the detection active but the safety activation disabled, so that a material can be test-cut to see if it would have triggered the saw.

Cheers,
Paul

Originally Posted by Optimark

If MDF has some metal in it as suggested, the SawStop manufacturer may have to add this material to the list of stuff you shouldn't feed into a SawStop table saw.

My men's shed took delivery of a SawStop saw, there is a list of stuff you shouldn't push through the system.

Wet wood (substantially wet that is, not dripping wet) conductive metal (timber with steel nails or screws embedded) etcetera.

Mick.

Have a look at earlier posts what was copied/pasted from wikipedia.

Sigh.

Repeat after me: "Wikipeida is not a primary source," and then add "and is often written or edited by morons who have no idea about what they are talking about"

Take the 'metal and glass' bit with more than the usual 'citation needed' for Wikipeida.

It's the urea-formaldehyde resin that causes the wear; similar to the way that paint can be bad news for thicknesser blades. Citation (with pictures): Why you shouldn't put plywood on a jointer

Originally Posted by Master Splinter

It's the urea-formaldehyde resin that causes the wear; similar to the way that paint can be bad news for thicknesser blades. Citation (with pictures): Why you shouldn't put plywood on a jointer

Nice to get some agreement on the resin (see post 11 of this thread)
As an aside, I could find no reference to metal in MDF on Google except for the un-sourced Wiki page

Urea formaldehyde isn't the only component that can scratch metal. Siliceous material is a 'natural' component, & some woods contain lots. It can do a right number on blade edges & any other metal that slides over it. I've often seen tiny sparks when sawing some types of hardwood (& it was fresh wood, no embedded nails!). I've also learnt through experience to very thoroughly clean the surface of any wood that has been sitting about, to remove the grit that deposits there so readily. Despite my care, all of my plane soles have tiny scratches on them. I think it's just an occupational hazard for planes. Although the scratches may be unaesthetic, & ruin your chances of selling it as a mint collectible, it would take a lot of scratches over many years before it would have any significant impact on function..

Cheers,

Whatever your shooting board is made of, I would keep it smooth and well waxed. If it's smooth and waxed, then your plane will be running on the wax, not whatever is in the wood. It will also be a lot easier to use, and more fun.

My SB is made from melamine, with hardwood edges to run against to stop abrasion and also to improve life and accuracy of the edges. The whole lot is waxed, and very slippery smooth to use.