Dado set for 20mm bore

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Peter G Denmark

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First of all - pardon my English – I am from Denmark, so bare with me.

I found a Wadkin AGS 10 for £170 - very dirty, and with some rust on the table, but otherwise perfect, and fitted with the long right hand extra table.

Only drawback is, that the arbor is 20mm and i really like dado sets (i know that dado is an American term, but the Wadkin instruction manual calls it dados - so what are you gonna do?).

Now - before the hecklers take a bite out of me, i know there are risks using a stacked dado set, and there are more elegant ways of cutting grooves etc.
But the Wadkin doesn't have a brake, so the inertia from the extra weight of the dado stack, that can cause the arbor nut to loosen, isn't a problem. I've used dado sets before, and i just find them handy, and if it's good enough for Norm - it's good enough for me.

Living i Sweden, is like living in a developing country wood working wise. The lumberyards only sell plywood up to 12mm, the solid wood you can get is mostly spruce and pine, no sharpening service, so you have to try and fix your blades and router bits yourself… You can order things special, but then you get ripped off (60£ for a 1200x2400 18mm low rent plywood at my local marked).

With that in mind, it’s hard to find a solution when looking for a dado set with 20mm bore. The idea was to buy a set with 5/8 bore and have it custom bored up to 20mm. But a typical dado set has 2 outside blades minimum 5 chippers, a couple of spacers and some shims. I need it all the adjustability I can get, because plywood here is metric, so even the shims has to be fixed.

That’s a lot of items that has to be precisely bored, and out of the 32 machine shops I contacted, only one would take the job – for 10£ pr. item that had to be bored. That’s at least 100£ - just for the custom bore.

I found a place in America that will sell me at 6 inch dado set with 20mm bore (http://ridgecarbidetool.com) for 175$ plus another 50$ for shipping, which is ok, but the taxes here are so, that before I have it in my hand, the blades would cost me 350$ for at set of blades that's worth 109$. I don’t mind paying for blades, if I get what I pay for, which is not the case here.

Can anybody help me with some ideas, that don’t involve me buying from the states, or having to rely on some local machinist? Hyperlinks, skilled persons, emails, anything – pleaaaase?

I suppose if anyone had a used 5/8 inch wadkin arbor I could by, I would be golden :D .

Thank you.
 
Make an adaptor for your 20mm spindle to take it up to 30mm and use a standard set

You will possibly need two adaptors of different length to cover the range of thicknesses

This would be a very straightforward machining task for a metal turner.

Bob
 
Thanks Bob - good suggestion, but it won't work.

The arbor is 31mm long, and with dados you don't usually use a flange. If i make some kind of adaptor, the nut and flange would take up 19mm of the arbor, and only leave me with 11mm space for a dado stack. I would like to have 19mm space.
 
My Wadkin is also 20mm. I bought a Freud set from Freud (at one of the Axminster shows) and as a special they bored a 5/8 inch set to 20mm for me and shipped it to me within a week.

I would have thought the best option would be to do the same - maybe somebody with metalworking facilities would possibly be able to offer help :-"

Misterfish
 
I don't see a problem either. I have an old Kity K5 which I've kept and still use. 20mm spindle and I use 30mm bore blocks.

All I did was get somebody to make me a couple of sleeves and made sure that they were fractionally less in depth than the blocks I use which means they dont need flanges as the clamping nuts with largish washer bear down on the block not the sleeve. Used these successfully for 20 years and they cost very little to have made.

There's always a way

Bob
 
Ok . the nut is 11mm wide and the flange is 9mm wide. This would leave 11mm on my arbor. The "diameter" of my arbor nut is 33mm. This would mean, that without the flange, the nut would only grip 1,5mm of the blade.

Maybe one of yuo could take a picture of your setup, since i might have misunderstood somesthing?

Best
Peter
 
Surely to use a sleeve with a dado set you would need a number of sleeves of different lengths to accomodate all the possible settings of the stack - long enough to hold the components centrally on the spindle but short enough to allow the arbour nut to tighten against the stack.

I suppose another alternative would be to have a series of 30 to 20 mm bore reduction rings, one for each component of the blade - I do use these with some 'ordinary' blades for the table saw.

Misterfish
 
Here are some pictures of my rebored Freud SD208 20 mm set along with the 'documentation' showing the wide variety of width settings that can be attained. (Requested by Peter)

dado1.jpg


dado2.jpg


dado3.jpg


And this compares the original size bore (that I use on my RAS) and the 20mm rebore as undertaken by Freud

dado4.jpg


To use sleeving on the arbour with a 30mm bore set I would need sleeves in a variety of lengths to allow tightening from 1/4 inch up to about 3/4 inch.

Misterfish
 
Thanks Misterfish.

As mentioned. Using sleeves would be a problem since the arbor bolt is to small to properly hold the blades without the flange. With the flange, only 11 mm would be left for blades on the arbor - not enough for a lot of applications.

When i find a solution, i will post again, to let people who find this post via google know what i came up with.

Thanks everybody :)
 
Peter G Denmark":1wz0uuly said:
Thanks Misterfish.

As mentioned. Using sleeves would be a problem since the arbor bolt is to small to properly hold the blades without the flange. With the flange, only 11 mm would be left for blades on the arbor - not enough for a lot of applications.

When i find a solution, i will post again, to let people who find this post via google know what i came up with.

Thanks everybody :)

Peter.

Without seeing photos of the set up it's difficult to know what shape the flange is, but being simplistic - why can't you replace the flange with a similar thickness but wider one? That way you wouldn't sacrifice any depth.

Series of different lengths to suit the dados isn't a problem surely for anyone with a decent engineering shop. When I got mine he cut an overlegth tube into the lengths I needed.

The guy used oversized section off the shelf with 20 bore (though they could bore out round or square section in the shop) and turned the outside to 30mm then parted it off in sections. He didn't charge anything so I gave him a fiver for a drink.

My neighbour had a Myford ML7 and made all his own arbours and sleeves etc very easily. I still don't see the problem though you might have fewer oportunities in your part of the world.

Bob
 
I'd go for a set of tubular spacers that are nearly as long as the dado stacks you want as Lons suggests.
The spacers should pass through the outer dado blade by at least half its thickness

As you want up to 19mm dado stack on 31mm spindle, I suggest a new flange, the same diameter as your current one but with a threaded bore, tightened by a pin spanner and for extra security locked by the standard nut which is some cases wont thread on all the way hence the threaded flange.

You might have trouble finding someone in Denmark to cut an imperial thread it the spindle has one, but you can buy LH thread imperial taps from Tracy tools online. You only need a carbon steel one to cut a single thread - these are cheaper.

Bob (another one)
 
@ Bob

What a great website (Tracy Tools), and your idea i a good one.

My arbor is a left hand 20 mm metric, with a 1,5mm pitch, but i can't seem to find one on their site. I've written them an email asking their advise.

If they can get me that 20mm tap, i might as well ask them if they can get me a LH 30mm DIE nut. That way i could thread 20mm inside, and cut 30mm on hte outside of a spindle, and get a 30mm arbor nut. That way i would effectively have converted my saw to a 30mm for good. Hope they can help me.
 
Tracy's pricing is all multiples of the basic tap or die price

left hand (tap or die) +200%
HSS or ground thread taps & dies +200%
Extra long taps +100%
Dienuts +100%

I have been trading with them since 1970s and have found them very good indeed.
They are only just getting into online sales so that might be a little flakey as they find their (web?) feet.
Bob
 
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