Alternative guarding for TS200 when tenoning.

[Rhossydd]

One of the things I really wanted to be able to do when I bought a table saw was cut clean tenon shoulders. With the standard guarding on the Axminster TS200 that's impossible.
So a new steel riving knife made to just below the maximum height of the cut was relatively easy. Guarding seemed more complicated.
What I thought might work nicely is shown below. An A4 sheet of 6mm thick acrylic sheet bolted onto the top of the standard fence.

I'd expect to use this in conjunction with the sliding table fence seen in the bottom of the shot, so the rip fence is just being used as a guard support.
There are still some refinements to complete, rounding off the edges and corners, but the whole assembly is remarkably solid.
Any comments on this ?

Even at maximum height the blade is just clear of the guard, so it could be used for more than just tenoning. The clear screen would certainly make seeing what you'd cutting much easier. It will obviously need a cunningly shaped push stick to work through under the panel if I choose to rip anything with it on.

 

[Tim_H]

I have done something similar but with clear acrylic mounted on a stand alone met mount held down with magswitches. I think I borrowed the idea from Steve Maskery.
It gives you a bit more flexibility in placement.

I will see if I have can load a picture later.

 

[Rhossydd]

magswitches.

That's a good idea, a bit pricier than four M6 bolts ;-)

 

[Noel]

Looks well but bear in mind acrylic is less impact resistant than polycarbonate which, I think, is the preferred material used for machine guards.

 

[Tim_H]

Varnished MDF, with 6mm acrylic A4 sheet screwed on, a couple of holes drilled in with a Forstner bit for the magswitches.

It would be better with Perspex, which is more impact resistant, however it is not designed to come into contact with the blade just keep your hand away from the blade. I really need to build a suspended guard that is not mounted to the riving knife, another on my list of things to do!

Obviously not needed here as the blade guard is,still in place and a magswitch is removed for illustration purposes.

 

[woodbrains]

Hello,

Perspex IS acrylic and neither are impact resistant, they are brittle and shatter with impact. As Noel said you should use polycarbonate. Industry mandates its use (or similar) and does not allow acrylic. You are not compelled by industry standards, but just so you know. A guard that can shatter in your face is less than useless!

Mike.

 

[Noel]

Yep, look for the likes of Lexan or Makrolon, two brands (although slightly different in composition) of polycarbonate. Acrylic is for greenhouses, baths and watches, not guards IMO. Simply not worth the risk. The above guard may not be designed to come into contact with the blade but ..............

 

[Tim_H]

Materials not quite right, design could do with height adjustment as well as replacing the acrylic with polycarbonate, I may well change it over.

My mistake I did mean polycarbonate rather than Perspex, (I can not even blame my slightly odd spell checker on this one). Perspex which is also known as polymethylmethacrylate or PMMA was good enough for spitfire canopies and shatters nicely which is how hard contact lenses came to replace glass ones but that as they say is another story!

 

[Rhossydd]

Yep, look for the likes of Lexan or Makrolon, two brands (although slightly different in composition) of polycarbonate. Acrylic is for greenhouses, baths and watches, not guards IMO. Simply not worth the risk. The above guard may not be designed to come into contact with the blade but ..............

OK, taken your advice there and changed the acrylic sheet for Lexan.
Although I wonder what would have to go wrong to shatter 6mm acrylic in this particular situation, it's pretty tough stuff.

 

[woodbrains]

Yep, look for the likes of Lexan or Makrolon, two brands (although slightly different in composition) of polycarbonate. Acrylic is for greenhouses, baths and watches, not guards IMO. Simply not worth the risk. The above guard may not be designed to come into contact with the blade but ..............

OK, taken your advice there and changed the acrylic sheet for Lexan.
Although I wonder what would have to go wrong to shatter 6mm acrylic in this particular situation, it's pretty tough stuff.

Hello,

It is not what you can think of that causes accidents, but what you can't!

I know it being picky with semantics, but acrylic isn't tough, in the accepted sense of the word. It is hard and it is brittle, which precludes toughness. If you look at your design, which is good BTW as a functioning guard, but introduces a row of stress raisers ( the drilled holes for fixing the plastic to the wood) in the case of an impact, such as an off cut flying, or bashing it with a length of wood, it would crack disastrously and likely fly off back at you. Better safe than sorry!

Mike.

 

[Rhossydd]

It is not what you can think of that causes accidents, but what you can't!

The skill in risk assessment is to imagine all possible problems and weigh their likelihood and consequence.

but introduces a row of stress raisers ( the drilled holes for fixing the plastic to the wood) in the case of an impact, such as an off cut flying, or bashing it with a length of wood, it would crack disastrously and likely fly off back at you.

The second issue is a non-starter in my workshop as I never pass timber above a moving blade. Also the fence clamp would probably fail before the acrylic would break.
Whether the little TS200 is capable of punching out an off cut with sufficient force to shatter 6mm acrylic is more debatable. It may not fit a precise definition of 'tough', but just try breaking a bit with a small piece of timber, it's not easy.

It's also worth keeping in mind just how thin and lightweight the original guard on the saw is too, just a couple of mms of thin plastic.

Better safe than sorry!

As I said I've changed the material anyway. Lexan is not only a more suitable material for this type of guard, but it's also easier to work and cheaper too.

 

[woodbrains]

The skill in risk assessment is to imagine all possible problems and weigh their likelihood and consequence.

If you could actually do that, a guard would be obsolete! I'm thinking 'TITANIC'.

Mike.