Routing Aluminum - DIY T-Slot Track

[marcros]

There was some 3/4 for sale on the forum the other day.
Alternatively I have some 1/2" which I could sell you. Mine is the rutlands stuff which I bought a pack of when it was on offer.

 

[Teejay]

I can't see 16 feet of t slot track on Rutlands any more, I need a couple of pieces which are about a metre long.

I also don't know what gauge size to get (1/2 or 3/4), which is more useful for a table saw?

The first might be because retailers do tend to change their product offerings over a five year time interval.

The second, slightly more serious, answer (from me) would be that very few people have ever made a "homebrew" table saw bench that's safe, reliable and accurate. If you do have the skills to do that, you probably don't need to buy aluminium extrusion T-track!

Bigger table saws use 3/4" slots; smaller saws tend to be non-standard (not 1/2"). I can't think of a reason, nor an easy way, to add a T-track to a saw table that doesn't already have one.

Anyway, you'd be better off with a sled: Do some Googling or use the search function on the forum for "table saw sled". It's an easy-to-make option that will give most of the function of a T-slot for accurate square cuts and mitres. Apart from holding down a guard, I can't think of other uses for a slot on a table saw (than a mitre fence).

E.

I have the following table saw which I really like:

The problems I have encountered are that 1. The fence does not travel far enough to the right to be useful and 2. I want the fence to span the entire length from front to back for accuracy 3. I have made a large plywood top for the saw with zero clearance so that there is more support for large wood cutting projects.

Thank you for your reply. I thought that aluminium t-track would be better (easier, cheaper and stronger) than buying a router bit and cutting out a track from the 1/2" plywood sheet I have put on top of my table saw for doing larger ripping projects like large sheet goods and the likes.

I would use the track for a mitre fence, featherboards and I was already wanting to make a table saw sled but this also requires t-track or some other slot to run along.

It sounds like 3/4" would be my best option?

 

[Eric The Viking]

You don't need track. A sled can run on the sides of the table.

The reason for a short fence is avoiding kickback. If all you ever do is cut man-made sheet materials on the saw, kickback is unlikely, but otherwise it's a real danger.

A short fence stops just after the leading teeth of the blade. The piece of stock between the fence and the blade is the main suspect for kickback, which happens when the rear or top teeth catch it and throw it with considerable force in unpredictable directions, but almost always towards vulnerable parts of the operator! It's not a neat trick - on small saws you can get quite serious injury, and on larger saws it can be a killer.

Three things minimsie the risk: (1) a good crown guard, (2) a properly set riving knife, (3) a short fence.

The short fence allows the stock to move sideways, away from the blade once the cut has been completed. It doesn't have to move far, just safely out of contact with the blade, so you can achieve the effect of a short fence with a thick facing (say 1-2cm) on the front part of a long fence, as long as it's well secured to the fence and can't itself move.

Get Steve Maskery's tablesaw DVD, which covers all this stuff (http://www.workshopessentials.com). He demonstrates kickback on it, ironically with man made board, and the example is somewhat shocking (well, it scared me!).

Even on a small saw, there is a surprising amount of kinetic energy available to be 'given' to a piece of stock in kickback, which is why it's so dangerous. You can calculate how much based on the diameter and mass of the blade and its rotational speed.

A few years ago I was trying to add an electrical brake to my SCMS, a project I haven't completed because it's more of a technical challenge than I expected. I did some experiments, dumping the energy of the blade into a mains electric lightbulb. It did work, but the first time I tried it the bulb just blew in one bright flash. And the second time too, using a much larger bulb (I'm not that dumb!).

In a table saw, a lot of that kinetic energy is available to create kickback, to which you can add energy from the motor (power in Watts multiplied by how long the kickback acceleration takes in seconds). Generally, the bigger the blade diameter the faster the exit velocity, too.

Regarding your own saw: the biggest single obstacles to accuracy are probably the alignment and rigidity of the fence. It must stay exactly parallel to the blade at all times (and that goes for the movement of a sled, too). Alignment will affect safety, how clean the cut is, and accuracy too.

If you can adjust the saw, align the blade to be parallel to one edge of the table (probably the left one) and then use that edge as your reference for the fence. We're talking about it being parallel to within 1/100ths of a millimetre ideally. If you can't adjust the saw, you will need to align the fence to it, and a sled is probably impractical. Truthfully, you may find it hard with the saw you have, as it's really intended for construction sites, where portability is important, and nobody needs accuracy to 1/2mm in OSB.

As mentioned earlier, Steve M. has a really good fence design, which, IIRC, uses a piece of angle as the rail to run it along. The rail can be as long as you like.

 

[Teejay]

Wow, thank you for the detailed reply. I would happily fork out for the DVD set which everyone raves about and Steve is a good guy who knows what he is talking about. My problem is that I am of the mindset that I actually would rather spend the money on components to complete the project, rather than buy the DVDs AND have to buy the materials as well unless by buying the DVDs I end up spending the same amount using cheaper materials to construct a better finished end product with the knowledge instilled by Steve. I expected this to be a challenge but it is becoming onerous. If I could see a picture of what you have described that would be a great help.

My plan was the build a bigger surface area for the reasons I listed before which would be used for cutting larger (heavier) materials down. I will use a sled for cutting smaller parts, particularly for the cabinets I plan on construction.

I constructed a frame out of CLS which I connected to the inner edge of the metal table supports using bolts to make the surface level and for added rigidity. When I checked the table for true in relation to the actual blade, it was out of true enough to be noticeable. I think that building a sled which runs along the existing edges is a bad idea, I was going to make someone similar to this: https://www.youtube.com/watch?t=36&v=grl-4G0qzuU once I got the track issue sorted out.

What type of rail were you describing and how is this incorporated?

 

[Teejay]

Is Steve's design like this one/the one you had in mind? http://vsctools.com/diy-table-saw-guide-rail-steps/

 

[Eric The Viking]

Not sure I see the point of the tube.

A fence would run on the angle iron alone just as well, and it's out of the way. I think he's trying to fit a pre-existing fence to the table.

Steve's only needs angle for the guide rail, IIRC.

 

[Teejay]

Are there any pictures of ones that people have made using Steve's DVD?