# Adapter for table saw arbor?



## DennisCA

I read something in an old post here about making a sort of slip-over adapter for a smaller arbor so you'd be able to mount 30mm blades without using inserts. I got a 20mm arbor and while fiddling with the inserts isn't that bad I wonder if the idea is practical if I wanted to get a longer arbor though? I might as well turn it into a 30mm one then too. 







What I am thinking is a round 30mm piece with internal threads that simply screws onto the current arbor, this is then the new bigger arbor. Sounds pretty simple to me. But I am not sure if that would work or not, maybe I am overlooking something? Maybe there's a risk of the whole arbor coming loose (perhaps it's no bigger than the risk of the nut coming loose during regular operation) or something else I've overlooked?

Is there perhaps someone who does this kind of job routinely or would I have to start looking for local machinists?


----------



## wizard

Why would you want a longer arbour?


----------



## DennisCA

Because of something that causes lots of derails on this forum and that I wanted to avoid talking about for that reason. 

Let's just think of Norm for a hint.


----------



## wizard

So you do not want any help then


----------



## DennisCA

I just wanted to avoid the dado debate... There, happy? Dado, dado, dado, I said it three times and now we're done for!


----------



## wizard

well turnip you then


----------



## DennisCA

I answered all your questions despite your unpleasant tone and all you got in response is an insult. Well pineapple you, you foul language alert.


----------



## wizard

:lol:


----------



## Myfordman

It is a job for a machinist really as it is vital the adaptor is perfectly concentric with the original shaft.
The last thing you need is a wobble with a full stack mounted.
A good solid saw with plenty of power helps too.
Also helpful if there is no brake or only a gentle one on the spindle.

Nought wrong with a dado head sensibly used despite what most here will tell you.

MM


----------



## wizard

How can he be helped if he unwilling to say what he is trying to do, there is no way i am going to give advice on something that may be dangerous. Then there is the cost, is the motor of the right HP, is the shaft a motor shaft, if so it may be a problem. Is he planning on doing it himself? Hi might just as well have asked how long is a piece of string. I am willing to help where i can if the person wants help but not when i get a reply like that.


----------



## DennisCA

There's practically only one reason one would want a longer arbor and I suspect you know that, I preferred to just leave it unsaid because I've seen the drama that has erupted in the past on this board in those discussions. But I acquiesced and told you, in a joking manner to indicate there was no hard feelings despite this stubbornness, and then you told me what I assume was "f*** you".





As for relevant information to anyone who cares, the motor is ~3.3HP and 3-phase, the arbor is not directly connected to the motor shaft but uses a drive belt, the saw is an industrial machine from 1976 and given the time it takes to spin down I don't think it has a break.

If this where feasible I'd have a machinist do it, be nice if there was someone who had done it before and knew what it was for or about, then I wouldn't have to go hunting some local machinist (don't know anyone suitable locally), I wouldn't have issues handling such a thing online with a UK or german machinist or some other country. Of course it'd depend on what it would cost, too expensive and I might as well just keep saving for a router and build a table.

The idea I had though was if one would make it internally threaded so it'd screw onto the arbor the same way you screw on the nut, from what I saw in the older threads (and it was hard to visualize what people where talking about there) they had some different setup to achieve a diameter increase. I think my idea sounded simpler and the increase from 20 to 30mm in diameter ought to leave the arbor flange with a useful rim still, but it'd new need flanges to support the blades.


----------



## RogerP

It can be done but will need someone with a lathe and expertise. He/she might well need the shaft assemble to ensure it's concentric when fitted. It would cost quite a bit. As you inferred it's probably better to get a cheap router and make a simple table.

I've never seen such an item for sale.


----------



## MickCheese

I have no experience or expertise but just a thought, would it be possible to remake the whole assembly with a larger shaft? After all it's not part of the motor. Or is that just a stupid idea and likely to be very expensive?

I cannot help thinking that a sleeve over the existing shaft could be asking for trouble. 

Mick


----------



## wizard

Motor is big enough no problem there, all you need to do now is cut the existing thread to the full extent of the shaft, it should be a left hand thread, the extinction will have to be drilled and taped in a lathe again using a left hand thread. simples


----------



## seaco

I could possibly do this for you but I'd need some measurements and the thread size you have... I think to be on the safe side it would be an idea to add a grub screw that went through into your original arbor for added security...


----------



## DennisCA

I was hoping to avoid that to make any modification reversible. Could one use loctite or something instead, then it ought to be very firmly there. Perhaps red loctite which would require heating the part to get it off again.

That is also why I was thinking the internal threaded part would only be as long as the threaded part of the arbor, the rest would be smooth. I also don't want to be taking the arbor off the machine, that veers into too much work/effort to be worth it.


----------



## wizard

You seem to know what you want so just take it to a local engineer and get a quote simples, or have you nothing better to do and you just need someone to talk to.


----------



## monkeybiter

Maybe the OP is wondering if anyone has done a similar mod, to benefit from theyre experience. 

Or maybe just someone pleasant to talk to.


----------



## wizard

Maybe he should go and buy a lathe then he can do it just as he wants it :wink:


----------



## DennisCA

Is there something in the water in cornwall.


----------



## Spindle

Aluminium sulphate in Camelford :wink: 

http://en.wikipedia.org/wiki/Camelford_ ... n_incident


----------



## wizard

:lol: fish


----------



## seaco

DennisCA":1x6ufan9 said:


> I was hoping to avoid that to make any modification reversible. Could one use loctite or something instead, then it ought to be very firmly there. Perhaps red loctite which would require heating the part to get it off again.
> 
> That is also why I was thinking the internal threaded part would only be as long as the threaded part of the arbor, the rest would be smooth. I also don't want to be taking the arbor off the machine, that veers into too much work/effort to be worth it.



Dennis I must admit you do seem to know exactly what you want already so asking opinions on here does seem a little fruitless. I personally think a physical connection between the two arbors is a must but obviously your entitled to your opinion (sorry but I retract my offer to make it as I don't want your health on my conscience) if you get it made I'm sure members here would like to here the results...

I do use a dado on my Unisaw so an extended arbor doesn't bother me, your safety does... :wink:


----------



## wizard

It was nice of you to offer


----------



## DennisCA

seaco":1jyb2bka said:


> Dennis I must admit you do seem to know exactly what you want already so asking opinions on here does seem a little fruitless. I personally think a physical connection between the two arbors is a must but obviously your entitled to your opinion (sorry but I retract my offer to make it as I don't want your health on my conscience) if you get it made I'm sure members here would like to here the results...
> 
> I do use a dado on my Unisaw so an extended arbor doesn't bother me, your safety does... :wink:



I don't know what is safe or unsafe, I don't have experience to know that or not, my idea was just a suggestion I threw out so I could learn if it was good enough or not, obviously you don't feel it's good enough. I never said I'd refuse any other solution. But OK.


----------



## monkeybiter

Obviously after switching off the motor and as the motor/pulleys slow down, any cutter will try to unscrew it's self until stationary. Clearly for a single blade a tight nut is sufficient, even with any braking system. However with a more massive cutter the 'unscrewing forces' will be greater. As suggested earlier a positive mechanical lock holding the spindle extension and/or retaining nut would be inherently safer than a reversible bonded retention method. I'd go for grub screw breaking into the path of the threads as an easy and positive method that could be removed without removing any original function.


----------



## Spindle

Hi

Whilst I appreciate the concerns for the safety of the OP I have to point out that the torque at the spindle tending to tighten the LH thread during start up will be far greater than the torque tending to loosen experienced during run down on a non braked spindle.
Using a locking feature can actually be detrimental in that it prevents the spindle self tightening under start up.

Hence lathe chucks only needing to be positively locked if the lathe is run in reverse.

Regards Mick


----------



## monkeybiter

Good point, thank you.


----------



## doorframe

DennisCA":3s0qvmu0 said:


> Is there something in the water in cornwall.



Trolls.


----------



## seaco

Spindle":1yb7brec said:


> Hi
> 
> Whilst I appreciate the concerns for the safety of the OP I have to point out that the torque at the spindle tending to tighten the LH thread during start up will be far greater than the torque tending to loosen experienced during run down on a non braked spindle.
> Using a locking feature can actually be detrimental in that it prevents the spindle self tightening under start up.
> 
> Hence lathe chucks only needing to be positively locked if the lathe is run in reverse.
> 
> Regards Mick



Good point Mick but on the other hand a mechanical fixing will stop any movement in either direction so in my opinion would still be safer!


----------



## Spindle

Hi Lee

Each to their own - but have you ever considered why grinding wheel retention nuts aren't locked?

Regards Mick


----------



## seaco

Hi Mick

With due respect we aren't talking about a nut or a chuck for that matter we're talking about an adapted arbour sleeve when the new sleeve is fully tightened a mechanical fixing is the best way to stop any possible movement in either direction...


----------



## DennisCA

I was wondering about that, might the existence of such a screw contribute to a weight discrepancy and introduce possible vibrations? Perhaps if one made two screws 180 degrees opposite from each other? Or is it not large enough to be noticeable?

(disclaimer: this is just me asking a question, not me making my mind up or rejecting any counsel or advice).


----------



## Spindle

Hi Lee

It doesn't matter how you look at it - it is a screw thread which has been designed to have a natural tendency is to tighten in use, adding a locking feature will prevent it doing this. If a locking feature were necessary manufacturers would have fitted one, (I can't think of an instance where this is the case).

Regards Mick


----------



## pcb1962

wizard":1ndtadja said:


> Motor is big enough no problem there, all you need to do now is cut the existing thread to the full extent of the shaft



You don't want to do that, you need the existing plain section of the arbor to register with the extension to ensure concentricity, a thread cannot play any part in that.


----------



## heimlaga

pcb1962":22vq1qw1 said:


> wizard":22vq1qw1 said:
> 
> 
> 
> Motor is big enough no problem there, all you need to do now is cut the existing thread to the full extent of the shaft
> 
> 
> 
> 
> You don't want to do that, you need the existing plain section of the arbor to register with the extension to ensure concentricity, a thread cannot play any part in that.
Click to expand...


I agree. That longer thread would make the arbour useless. The flanges would start to wobble and even if this was resolved there would be a much higher risk for metal fatigue and a sudden break in the arbour.


----------



## DennisCA

This reminds me, while I need the smooth portion of the original arbor to index against, I noticed that on longer dado capable arbors they can mount the blades right on the threads, they use a thicker acme thread. I would need the same setup on the sleeve if I want to use this to mount a dado stack.

On my current arbor I believe the threading is M18x1.5 LH and it is smaller than the un-threaded part of the arbor, so you cannot mount the blade anywhere but on the smooth part. 

I am not sure if I should leave any un-threaded surface on the newer sleeve? Or should I got for threading all the way, like american TS arbors seem to be. The coarse acme thread seems sufficient for a mounting a blade.


----------



## Spindle

Hi

The only way to ensure the blade or dado stack runs concentrically is to mount it on to a matched plain arbor - if you mount it onto a threaded section the thread clearance will result in the blade / dado stack being a loose fit, the outcome of which will be a lack of concentricity and balance.

Regards Mick


----------



## DennisCA

American table saws seem to have no clearance from what I can gather and the acme style thread seems to be designed so a blade can be mounted directly on it without clearance. My euro arbor has clearance and so it can only be used on the plain section. 

This seems to me, to be the only way one could make an arbor that is both capable of taking just one blade as well as a dado stack, from what I can determine on ameican saws, the arbor is designed so it can take one regular blade + flanges on it's smooth portion, then the rest of the arbor as an acme thread without clearance that is capable of mounting more blades without the issues you describe, though apparently there can be issues with shims falling into the valleys of threads as is mentioned here:
http://newwoodworker.com/usngstkddados.html


----------



## Spindle

Hi

I'd go for a plain arbour and a cup washer system with a series of spacers to allow differing width of blades to be installed.

Hope the diagram makes sense






Regards Mick


----------

