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Two micro-adjustable box-joint jigs

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Anonymous

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I recently acquired some plans of a micro-adjustable box-joint jig put out by ShopNotes, which is designed to be attached to a mitre gauge, which can be used either with a dado set on the table saw, or on a router table, if your table includes a mitre-gauge slot. At first sight, this jig seemed ideal, since it was micro-adjustable both for the width of the index pin and for its distance from the cutter. Pictures of the jig attached to a mitre gauge are at

http://f2.pg.photos.yahoo.com/ph/dldund ... /my_photos

Unfortunately, I found that the jig had some major drawbacks; the slight amount of play of the mitre gauge in my table saw's slot led to some imprecision, and so did the fact that the L-shaped bracket which formed one side of the adjustable index pin tended to flex, giving rise to further inaccuracy. To produce well fitting joints, a box-joint jig needs to be able to ensure that the index pin is adjusted so that the index pin is exactly the same distance from the cutter as the thickness of the pin. Any inaccuracy is cumulative, and unless the two parameters are identically matched, the joint will not fit. I found that, because the Shopnotes jig lacked any measuring device, the micro-adjustment was almost as hard to fine-tune as a jig without any micro-adjustment system.

In order to overcome the limitations of the ShopNotes jig, I decided to build a different version which would address its shortcomings. My jig, of which pictures are given at the same location as given above, is attached to a miniature crosscut sled, which has runners fitting into both slots of my table saw, effectively eliminating the sloppiness that results from a loose-fitting mitre-gauge bar. My jig has a solid, fixed-width, but interchangeable, index pin, and it incorporates a dial-gauge in the micro-adjustment system, making fine-tuning of the jig's adjustment quick and easy.

Since dado sets are apparently illegal in the EC, my jig would need to be adapted by EC users to have only a single runner for use on a router table.

I am hoping to publish an article on my jig in Australia, and perhaps also in the US, but I would be happy to e-mail a copy of the article to any forum member who may be interested, if they message me with their e-mail address

Rockerau
 

devonwoody

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Hi Rocker

I have had a look at the webpage and congratulate you on a very wellset out site. Dado sets are OK if used in an home setting providing no commercial use is being made with the equipment according to an article posted on this site sometime ago.
I hope oneday to graduate to your standard so keep up the good work.

John
 
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John,
Thanks for your kind remarks about the photos that I have put up on the Yahoo site. Hopefully the site is not infested with viruses, like the previous site I was using apparently was.

From what you say, it seems I am misinformed about the legality of dado sets in Europe. But I seem to remember someone saying on the Australian forum that table-saws over there are sold with short arbors, which cannot accommodate dado sets; no doubt there are plenty of older saws about that were sold before this regulation came in.

Rockerau
 

Adam

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Provided no other method is viable, and an approrpriate safety gaurd is in use, I beleive they are legal even in a commercial shop. I'm sure you buy a dado head for a felder - even when used in commercial premises?

Anyway, in answer to your question, in general, most saws are produced with an arbour that is too short to take a dado set, although Scheppach seem to be incorporating longer arbours on their latest cast iron tables, to allow a "moulding" head to be fitted.

Adam
 

Dewy

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They became illegal in commercial shops on 1st January Adam.
Many who have used them for years had to scrap their saw benches before the new safety laws came in.
Rockerau, you can use dado heads if the saw was made with a longer arbor & has no electric brake.
All saws made here for years have been unable to accept them.
The only cure, I'm afraid, is to buy an older saw for use with dado head cutters.
I think it was 1998 that saws started fitting blade brakes so most saws before then could use them.
Radial arm saws are the only ones made now that will accept dado heads.
 
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It seems a bit ridiculous to ban dado sets; I can't see that they are any more dangerous than an ordinary saw blade. I can understand why the UKIP seems to be making some headway in Britain, if the EC is imposing this sort of legislation. But I suppose this is not really a suitable place to discuss politics.

Rocker
 

Adam

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Dewy,

When I read the regs in detail, all I could see was that it was illegal to use them if another safer method was available. Also, it mentioned you must have an appropriate gaurd. Like I said, Felder do a long arbour, as to Scheppach now - I'm sure neither of these companies will have failed to check out the guidelines, perhaps you just need an upgraded brake to ensure it comes to a stop in under 10 seconds?

Is there a specific place where this is detailed in the regs I missed?

Adam
 

Dewy

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Adam,
I learned most from a commercial woodworking employer with large shop, apprentices etc on another forum.
You can also see how the HSE affect the use of dados on the Great British Woodshop site after David Free was using them in his imported Unisaw. Click here for GBW safety page.
 

Adam

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My intpretation of the information from that site (and I've seen it before) is as I said, there is no requirement for a commercial shop not to use a Dado head, merely that the "duty of care" means thay'd be hard pushed to justify a Dado had if they had a router. Provided the arbour meets the 15.5mm abour length requirement, and it has an appopriate gaurd and it stops within 10 seconds it's all fine, even on commercial premises (is how I read it still)

Did you read that site differently to me?

Adam

A quick look at the "Safe Working Practices - Circular saw Benches" - which is on the HSE website says

"A circular saw should not be sued for cutting a rebate or groove unless the blade is effectively guarded. This is because the normal saw guard cannot be used. Suitable alternative guards and fixtures are neccessary. Figure 7 shouws an example of one methods for rebating or groocing using Shaw gaurds. Where practicable the tunnel formed by the pressure pads should be designed to meet the requirements of Table 4 of BS EN 294: 1992(6)"

Given HSE applies to commercial shops (and not withstanding my comments on duty-of-care above) in the strictest sense, does that not say you can use a dao-head, with the appropriate guard?
 

Alf

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I know we've been through this before (I can't be bothered to search for it today) but I have a vague idea that braked saws were a no-no with dado heads. So wouldn't that mean you'd have to be breaking the, er, braking rules to have a saw capable of safely taking a dado head anyway? Or maybe not. Never mind; I'm sure I shall regret getting involved in this anyway... :roll:

Cheers, Alf
 

Adam

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Ahh, HSE also says you don't need a braked machine if in doing so causes a danger to the operator OR your guards are sufficient to eliminate any possibility of the operator coming into contact with the blade, in which case you have no restrictions in stopping time. I wondered if it's this mechanical limitation, which means only on a Felder can they afford to have some sophisticated braking mechanism?

Adam
 

Adam

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Alf":1927tv7y said:
Never mind; I'm sure I shall regret getting involved in this anyway... :roll: Cheers, Alf
Of course you will, but you've typed it, so are obligied to continue in the discussion :wink: :shock:

Adam :roll:
 

Alf

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asleitch":35or41cw said:
Ahh, HSE also says you don't need a braked machine if in doing so causes a danger to the operator OR your guards are sufficient to eliminate any possibility of the operator coming into contact with the blade, in which case you have no restrictions in stopping time.
Aaaarrgh! So the one point about which I was certain, isn't. Good grief, I imagine the lawyers could have a field day with this lot just deciding what constitutes "sufficient guarding". :roll:

Cheers, Alf
 

Chris Knight

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The one good thing you can say about the rules and regulations that issue from Brussels, and Westminster (like the dado thing) is that - apart from engendering a burning passion (in my case a desire to see the perpetrators hanged, drawn and quartered), it encourages versatility.

If you can't find a dado head to break the law with (or not, but who cares - if you haven't got one anyway?) then you will fiind a way to use a tailed router, a mulitplicity of saw cuts, an old woman's tooth, a tenon saw and cranked paring chisel, a plough with nickers and so on.

A small prize will be offered to the person declaring the most ways to circumvent the problem. Quality of prize dependent on quality of answers so you have a nice trade-off here. Ten thousand rubbish answers (which I suspect is enough (numerically) to win) may get you a splinter of some exotic wood dipped in?? whilst a dozen really good answers (if it were enough numerically to win) may get you something you won't throw in the trash. The prize will come from my very own workshop.

The first to respond might like to start a separate thread entitle prize dados or something similar - as I suspect we have rather departed from the original thread designation! Closing date for this super comp is 48 hours from time of this post.
 

Dewy

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The Wolfcraft router table, that is availible at many outlets has pictures & instructions for using a model that can be used for making box joints. I phoned about the extras needed & was told that they are illegal to sell here. It was only an aluminium bar screwed to the table that you used to slide the workpieces accross. I made one myself & found it so unsafe to use that I ditched it and have started making a box joint jig to fit in the mitre slot of the table. Being just a small bar on th table, there was no means of holding the work so the cutter snatched at the piece which could have dragged my fingers into the cutter. A purpose made jig will have the ability to clamp the work to the jig hopefully overcoming this problem.
 

Adam

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waterhead37":35c2g3lc said:
A small prize will be offered to the person declaring the most ways to circumvent the problem. Quality of prize dependent on quality of answers so you have a nice trade-off here. Ten thousand rubbish answers (which I suspect is enough (numerically) to win) may get you a splinter of some exotic wood dipped in?? whilst a dozen really good answers (if it were enough numerically to win) may get you something you won't throw in the trash. The prize will come from my very own workshop.
Well how about...

A) Just use a dado head and have done with it
B) Use a moulder head, and with some clever profiles, you get either a dado, or something pretty close
C) Use multiple sawblades, shimmed with some pukka spacers from your local engineering shop
D) Disconnect the electronic brake, and have it on a switch so you can have a slow run down on the saw when using dado head
E) Buy a milling machine, and get precision X-Y trenches
F) Run it through a spindle moulder
G) Run it through a router table
H) Use a router with a fence
I) Use a router with straight edge
J) Use a router with home-made jig
K) Use a tooth plane
L) Use a shoulder plane
M) Use a rebate plane
N) Use a bullnose plane
O) Buy a woodrat (very effective this - I've done trenches across a bookshelf side :twisted: )
P) Buy a Leigh dovetail jig - the bloke doing the demo said is was possible anyway
Q) Use an angle grinder/arbotech - bit rough but works well on garden furniture
R) Use a mafell chain morticer type thingy - but only a shallow cut
S) Use a mafell/festool hand-held circular saw
T) Use a chisel
U) Use a drill and clean up afterwards with a chisel/plane
V) Use a notched draw-knife
W) Use a morticer
X) Fake it, using a couple of dowels and an accurate 90 degree joint
Y) Put short blades in an electric planer
Z) Cover with a metal plate with just a small slot and leave for several months where green woodpeckers are known to be active :shock: Ok ok, running out of alternatives now...... :lol:

Hows that for starters?
 

Chris Knight

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Adam,

Not a bad start with 26 and all - but a trifle repetitive in parts (router and a fence, router and a straight edge) wouldn't you say a straight edge is a fence in this case or vice versa? And a bit weak at points - a chisel? Well yes but why not a pocket knife or a bodkin?

And what pray is a notched drawknife? Now a toothed drawknife, I could understand..
 

Adam

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waterhead37":2vqw4mka said:
Adam,

Not a bad start with 26 and all - but a trifle repetitive in parts (router and a fence, router and a straight edge) wouldn't you say a straight edge is a fence in this case or vice versa? And a bit weak at points - a chisel? Well yes but why not a pocket knife or a bodkin?
I consider a straight edge, and a fence to be very different, but yes it was clutching at straws slightly,

waterhead37":2vqw4mka said:
And what pray is a notched drawknife? Now a toothed drawknife, I could understand..
Doh, I'm getting muddles up between notches and tooths, toother drawknife is what I mean
 

Adam

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And Chisel isn't too far fetched, as it's a good emergency back up...

A1) Just thought of using a template and a bearing guided cutter
 
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