engineer / fabricator for table saw gear wheel inner sydney

[jbarch]

G'day
im new to this side of the fence - wood is my fix.

i have an SCM table saw with a damaged wheel on the "rack and pinion" that allows the saw blade to rise and fall.
i cant get a replacement.
can anyone suggest a fabricator local to inner sydney if possible.
it is a steel disc with a raised spiral that fits into a rack with curved teeth.

thanks

Jbarch

IMG_1641.jpeg

[Michael G]

A few extra photos so we can see the detail required and a measurement or two would be good. A commercial shop will cost you an arm and a leg, so the more detail you can supply the more likely someone here may stick their hand up to help.
The raised spiral thing sounds unusual. Please make sure that is detailed. If it really is a spiral then it may be something that has to be done on a universal dividing head or CNC mill.

Michael

[jbarch]

been a little busy lately, but i still need to attend to this.
some photos below.
the saw works terrifically except no rise and fall, so worth getting this repaired.

it seems to me that since there is a spiral slot cut into the disc, a spiral could be made up and braised in the slot. the piece would need to be about 4mm high x 1.2mm wide and tapered.

any thoughts, suggested fabricators or offers to make this up much appreciated.

Jason

IMG_1643.jpgIMG_1644.jpgIMG_1645.jpgIMG_1646.jpgIMG_1647.jpgIMG_1648.jpg

A few extra photos so we can see the detail required and a measurement or two would be good. A commercial shop will cost you an arm and a leg, so the more detail you can supply the more likely someone here may stick their hand up to help.
The raised spiral thing sounds unusual. Please make sure that is detailed. If it really is a spiral then it may be something that has to be done on a universal dividing head or CNC mill.

Michael

[PDW]

been a little busy lately, but i still need to attend to this.
some photos below.
the saw works terrifically except no rise and fall, so worth getting this repaired.

it seems to me that since there is a spiral slot cut into the disc, a spiral could be made up and braised in the slot. the piece would need to be about 4mm high x 1.2mm wide and tapered.

any thoughts, suggested fabricators or offers to make this up much appreciated.

Jason

IMG_1643.jpgIMG_1644.jpgIMG_1645.jpgIMG_1646.jpgIMG_1647.jpgIMG_1648.jpg

4 axis CNC mill or powered rotary table geared to table travel, plus a custom ground cutter, looks like to me.

I personally wouldn't touch a job like that with a barge pole. If I absolutely had to quote on it, I'd quote so high that you'd think I was out to bankrupt you.

But then I don't have a 4 axis CNC mill - should be a relatively trivial job on one of those. I think.

you have found an example of something that can be mass produced reasonably cheaply because it's worth setting up to make hundreds, but is quite difficult to make as a 'one off' in the average well equipped machine shop. And - I have a rotary table with input drive shaft that can be coupled to my mill's travel.

I'd look at some other way of dealing with rise & fall. It will be a lot cheaper and simpler. All you really need is a length of threaded rod and a bit of fabrication - that's what I did when I built my own big table saw some 25 years ago.

PDW

[SurfinNev]

Maybe a crazy idea here but could you convert to a normal rack and a gear to suit? Probably need some way of locking in position one height is set I would imagine.

Nev.

[RayG]

I don't think that would be too hard to repair, the raised portion looks like it's a separate piece pressed into the spiral slot. If the old spiral can be easily removed then it would be just a matter of winding a new spiral and pressing it into place... brazed into the slot would be sensible.

If no-one else wanted to try, I'd give it a shot...

Ray

[Stustoys]

Thanks Ray I'd been looking at that picture but it kept doing my head in. Its all cleared up now
Stuart

[BaronJ]

I've seen this sort of thing before ! It works in exactly the same way as the scroll spiral in a self centring three jaw chuck. In fact I would bet that an old chuck scroll might even work.

[jhovel]

I think that would be a great challenge to hand to Harty or Jason in Horsham! I would imagine they would do it on one of their CNC vertical mills with the scroll wheel clamped to the mill table in two or three passes. Neither old have any trouble writing the G code for it either.
How about I you two????

jbarch, does the rack have angled teeth an the spiral is parallel sided, or are the edges of the spiral parallel and the scroll is tapered? Hard to tell from the photos....

If the scroll is parallel, then the gap or the tooth width of the rack would be the cutter diameter to use - or smaller....

[jbarch]

glad to hear this is not straight forward but has excited a few folk.... i think.

re the rack, in plan the 'teeth' are curved, in section they are triangular, but tapering to one end.
the scroll appears to be tapered, but this may simply be due to wear. i would think that a 1.2-1.5mm thick parrallel spiral pressed into the recess would probably do the trick.

it is similar to a scroll chuck plate, though deeper.

if anyone is keen to have a crack at this i would appreciate it.

I think that would be a great challenge to hand to Harty or Jason in Horsham! I would imagine they would do it on one of their CNC vertical mills with the scroll wheel clamped to the mill table in two or three passes. Neither old have any trouble writing the G code for it either.
How about I you two????

jbarch, does the rack have angled teeth an the spiral is parallel sided, or are the edges of the spiral parallel and the scroll is tapered? Hard to tell from the photos....

If the scroll is parallel, then the gap or the tooth width of the rack would be the cutter diameter to use - or smaller....

[BaronJ]

glad to hear this is not straight forward but has excited a few folk.... i think.

re the rack, in plan the 'teeth' are curved, in section they are triangular, but tapering to one end.
the scroll appears to be tapered, but this may simply be due to wear. i would think that a 1.2-1.5mm thick parrallel spiral pressed into the recess would probably do the trick.

it is similar to a scroll chuck plate, though deeper.

if anyone is keen to have a crack at this i would appreciate it.

The teeth on the rack would have a similar form to the teeth on the back of a chuck jaw. You might find that the rack is quite worn as well as the scroll. From memory the one I dealt with had quite a high loading, lifting both the weight of the motor and that of the saw blade and spindle. I think that the motor was 2 or 3 Hp. I'm trying to remember the makers name...