Home made table saw.

[caretaker]

http://www.youtube.com/watch?v=f92MIxp9jTM

See this on utube what do you think, I have the saw, is there a better plan, any advise for me?

 

[RogerP]

No emergency stop, no riving knife/splitter, no guard. Very dangerous! Don't even contemplate it

 

[AndyT]

Ok, I know that back in the 70s Black and Decker sold accessories that did something just like this, using a circular saw attachment on an electric drill. THAT DOESN'T MEAN IT'S A GOOD IDEA.

The "table saw" shown has

- No Guard
- No riving knife
- No easily accessible off switch
- No dust extraction
- A fence that continues past the back of the blade.

What's more, the manoeuvres shown in the video - where he pulls the cut piece back past the still-revolving blade - is just asking for the wood to be thrown across the room.

He'd be better off buying or making a straight edge guide and using his saw the right way up.
(Actually he'd be better off with a handsaw.)

 

[andersonec]

If that fence is not parallel to the blade and with no riving knife he is going to get smacked in the face by a piece of flying wood very soon, that is if it has not already happened which I expect it has.

 

[Racers]

He was about to pivot that piece that was aganst the fence up to remove it and I gasped, luckly he didn't.

Pete

 

[baldpate]

I'm not sure there's anything wrong, IN PRINCIPLE, with making a table saw this way, and with using it in reasonable safety - although it is obviously difficult to incorporate ALL the safety feature which are present (by H&S mandate, I suppose, rather than buyer pressure) in even the cheapest modern products.

The problem with a video like this is that it suggests that once you've stuck your circular saw up through a sheet of wood & clamped to it a roughly-parallel bit of wood as a fence, you've cracked the problem. There's no understanding of the risks. No discussion of what safety features are missing, why those features are put in place on commercial products, and where the dangers lie; no discussion of what you can do to improve personal safety and reduce risk.

The user in this case obviously doesn't understand what he's doing wrong, nor WHY ! He only admits in subsequent dialogue that it's best to use a push-stick - I don't think he really believes how quickly the wood he's cutting can be whipped away leaving his fingers sliding into the blade. I imagine he doesn't understand that kick-back can happen with any wood (even mdf) if you do anything to force the cut against the rising teeth, and how (for example) the use of a short fence can help minimize the risk.

I will admit bias here. I have one of those B&D accessories + 5" circular saw which AndyT mentions, embedded in a larger home-made table. I do this from necessity. My loft workshop space is *severely* limited, so the 'table saw' is clamped in a workmate, where it can be swapped out for a home-made router table as needed. I don't use the table saw often, but I'm very careful when I do and to be honest, although it's only a 5" blade (1" cut at max) it scares me sh**tless. I only ever use a half-length fence and I'm very careful to clamp the main fence parallel to the blade. I never stand in line with the cut unless I absolutely must. If I stand in-line, I try to clamp a feather-board/hold-down aft of the cut to limit the effect of possible kick back. I use push sticks if there is any chance my hands will get within 6/7" of the cut; I will NEVER reach across the spinning blade except with a stick.

I believe (repeat, believe) I understand the risks I'm running (no riving knife, no crown guard, for example); I accept them, and minimize them. I do so out of necessity.

It's not the tool that at fault, it's the user ! But I suppose I would say that, wouldn't I :wink:

Chris

 

[andersonec]

I've put this up on here before now but it is the best explanation of how 'kick back' occurs and what causes it, http://www.dailymotion.com/video/x7d2vt ... _lifestyle

And this is the worst demonstration, after this you will see why you need a riving knife. http://www.youtube.com/watch?v=u7sRrC2J ... ure=fvwrel and he knew it was coming!!!!

Chris,
Even if you just cut a little groove into the table top and hammer in a thin sliver of wood, it's got to be better than nothing.

Andy

 

[AndyT]

Going back to what the OP wants, rather than what is on the video, if you want to get a way of power sawing smallish bits of wood but don't have a lot of cash to spend, I would strongly recommend that you look out for a cheap bandsaw. I have an old Burgess 3-wheel model from the 70s which soldiers on being really useful, and is far more versatile and a lot less dangerous than a diy tablesaw would be, and cut thicker sections too. (The main safety difference is that the blade pulls the work down onto the table, so if anything goes wrong there is no likelihood of the wood being thrown at you. )

Looking at eBay, bandsaws like this seem to go for £25 or less and attract very few bids, so it's just a case of watching for one to turn up near you. I expect the old ones are more solid than the current Clarke / NuTool / Power + branded equivalents.

 

[baldpate]

@Andy (andersonec),

thank you for that first video - it has added to my understanding, particularly of the way that the work piece can be spun off to the left (relative to the operator): also added to my fear of the little so-and-so. Unfortunately, my little B&D CS came without its riving knife, but you've persuaded me that it's definitely worth looking for a replacement part, or an equivalent saw with the knife, or some sort of substitute.

The only thing I can say about that second video - apart from the fact that it confirms the dynamics of the first (the way the blade spins the work piece away back in an arc ) - is that the man is a complete idiot to have used a push-stick/plate where the grip requires your hand to be so close to the peak of the blade. I use a home-made stick with the a high handle, well back from the blade (a bit like a hand-saw handle).

I also notice that he isn't using a half-length fence, which must surely add to the risk?

@Andy (AndyT) : I have toyed with the idea of a small three-wheel band saw for some time. The doubt I have is this : can it ever cut as straight as as a table saw (however small and crude, such as mine)? I'd love to be convinced, because I'm sure it would be a safer and more pleasant to to use than a TS. But straightness is paramount!

PS : apologies to the opening poster - I don't mean to take over your thread - I hope this discussion is useful to you. If not, just jump in and get us back on track!!

 

[AndyT]

Re: straightness of cut - to be fair, if you just push the wood along the fence, no you won't always automatically get a straight cut as you might with a circular saw. However, if you learn to follow the way the saw works, you can always follow a line accurately, but I would always expect to plane afterwards.

But then, you'd need a proper table saw with a good blade to not have to plane afterwards, as even though the cut would be straight it would not be very smooth - not smooth enough to glue to or paint.

 

[baldpate]

That's right - I certainly expect to plane afterwards with my set-up too, since it's not a proper table saw - something like a few strokes with a No. 7 to get a glue-ready surface.

Let's see what he opening poster thinks

 

[jimi43]

.......@Andy (AndyT) : I have toyed with the idea of a small three-wheel band saw for some time. The doubt I have is this : can it ever cut as straight as as a table saw (however small and crude, such as mine)? I'd love to be convinced, because I'm sure it would be a safer and more pleasant to to use than a TS. But straightness is paramount

Just to dispel this myth...I show this every time it comes up...Andy is spot on..my old Burgess 3 wheel bandsaw WITH a Tuffsaw blade and LV guide blocks..and zero clearance insertion plate cuts perfectly straight...

...and a table saw doesn't cut curves like this either...

The table saw in that video is blinkin' lethal...forget that idea would be my recommendation.

If you want to cut huge panels...get a guide rail system for a circular saw or a cheap long clamp. Even a batten clamped to a panel would be a better idea.

Jim

 

[caretaker]

Thanks all for adivise and comments, it's back to my trusty safe hand saw.
Reg

 

[Eric The Viking]

@ baldpate:

Actually a short fence is considerably safer than the full-length front-to-back type.

If you set it up properly, it finishes just behind the front teeth of the saw. Any work running along the fence is then released as it passes the front teeth. Unless something else intervenes, such as an inexperienced operator, there's nothing to cause it to be pushed into the back teeth, causing kickback.

In contrast, a long fence with toe-in (easily mis-adjusted that way on smaller, cheaper saws) will promote kickback: once cut, the wood pinches the blade.

 

[baldpate]

Since I always listen carefully to what you guys have to say, I decided that some safety improvements to my home-made table saw were overdue. Here's what I have added as a result of your comments (except the short fence, which I was already using).

This is the riving knife I made from 2mm mild steel. I was advised in another thread that tool steel would have been a better choice, and I agree, but this is what I had to hand. This seems to work OK, probably because this is only a small saw, so any pressure tending to deflect the knife is exerted no more than a few inches from where the riving knife is clamped below the table, and the pressures aren't great with the sort of cuts I make.

Next, an NVR switch (this will serve my new router table too, which can be mounted instead of the saw table).

The crown guard isn't clamped to the RK (which only rises to the apex of the blade, not above) but is linked indirectly to the fence. The transparent part of the guard is a bit messy - my first attempt at weld-gluing plastic - but quite solid. I think it will protect me from many accidental contacts with the blade, and from a lot of flying debris.

Finally, the detachable short fence (inspired by Steve Maskery's design, but much more primitive).

The one thing I haven't addressed is improving dust extraction. I just don't have the space or power for a proper system in my loft workshop. Most of the debris seems to end up in the collector box fitted under the saw, and for the rest I rely on a half-face mask. Not ideal, but at my age I'll probably snuff it from something else before the residual dust gets me!

All in all, I think this is now a safer saw, although still not as flexible as real table saw. I hope also it adds some weight to my thesis that a home made table saw isn't intrinsically an unsafe tool.

Chris

 

[Hardwood66]

Home made machines! That makes my skin crawl, give me a wadkin over plodkin anyway