Making wood spirals - could this be done?

[MadKad]

Hi

I am building a cnc machine, and I was thinking would these be able to be made on a CNC router

http://www.arka-shop.co.uk/acatalog/WMEX006.jpg

also these would need to be bang on mill sizes ie. 8mm at the biggest gauge point

Thanks

[ger21]

Holding them down will be the tricky part. That and keeping the points from breaking off.

[NEATman]

MadKad-
You may want to read up on steam bending of wood. That way you could form the wood in a "toothpick" shape, (tapered to a point on each end) then steam the wood in a straignt shape, then put them on a fixture of some kind to hold them in the spiral shape while they "harden".
http://www.allwoodwork.com/article/w...nding_wood.htm

NEATman

[greybeard]

Neatman's suggestion would also give you a much stronger spiral. You don't mention the use, but any strain would easily crack most woods across the short grain points, and you've got plenty of those.
John

[MadKad]

Hi thank you for your replies.

I thought of steam for them, but I then thought about the drying time after as it is hard wood and they are made for body jewellery (the ear)

the size has to be spot on to gauge, would steaming afect this? how long for drying after by air dry?

I have to think of all that, with a cnc I thought about the splitting, and thought that tacking a bit off at a time would be best, also for holding I thought that not cutting parts of it all the way down and just cuting them by hand after.

With something like this maybe doing both ways and finding what would be the better and best way would be the way to go, I was hoping that maybe some one had tried something like this

again thank you all for your time

[greybeard]

MadKad - Two questions -
I'm not too clear what you mean by 8mm at the biggest "gauge point". Does this mean, taken from your linked photo, that the overall size is about 60mm ?

Is this a limited quantity, just a couple of pairs, or are looking to produce a large number ? The final approach might differ, depending on quantity involved/budget etc.

While I like a challenge, I think the potential problem with losing a tip when you've got to a finishing stage, like polishing the surface, might be quite high if you cut them from the solid. Not so perhaps if you were working in lignum vitae, or similar
If you were looking at a reasonable number, then holding jigs for cutting and/or polishing might be worth considering.
Good luck,
John

[MadKad]

Originally Posted by greybeard MadKad - Two questions - I'm not too clear what you mean by 8mm at the biggest "gauge point". Does this mean, taken from your linked photo, that the overall size is about 60mm ? Is this a limited quantity, just a couple of pairs, or are looking to produce a large number ? The final approach might differ, depending on quantity involved/budget etc. While I like a challenge, I think the potential problem with losing a tip when you've got to a finishing stage, like polishing the surface, might be quite high if you cut them from the solid. Not so perhaps if you were working in lignum vitae, or similar If you were looking at a reasonable number, then holding jigs for cutting and/or polishing might be worth considering. Good luck, John

Hi

well there would be two sizes to take into account, and they are 1 the other all size the person would want like say 60mm lenght made into a spiral, then the gauge would be the other and lets say it had to be 8mm that would be the fattest part for the wood.

A polish would be needed, but if the end product was to a high standerd of finish then it wouldnt be that hard to get a polish.

As for amount, it would be alot over time and it lots of different sizes, so yes jigs would be a good idea but thinking what would be the best way I am unsure.

Maybe making a spiral in MDF like a mold idea so that the wood could sit in once one side of the main spiral was done

[greybeard]

If I read right, your customers are going to give you the length of the spiral they want ?
Good grief.
So potentially every one is different, so a spiral jig is out.
If you do go the cnc route, then I'd suggest using the outside "waste" area as a means of securing the block down to the machine base. (This at least could fit into a clamping jig if your blanks were all the same size.)
Then leave small "tabs" at intervals across the spiral to support them when you cut the second side. Remove these by hand as part of the finishing process. You would also need to leave just a few small tabs on the outside to secure the spiral to the waste wood, rather than try cutting it out completely, with disastrous results.
John

[MadKad]

Yer that is what I was thinking, if they was going to be the same lent but I was just going to use different hard woods and do say different main gauges like 6mm for 1 then 7mm, 8mm etc

what do you think would be the best way to hold the work?

Thanks

[greybeard]

Start with the blank piece of hardwood. Around this is a square frame, thicker than the thickest blank, with set screws mounted through the sides to lock the blank in place.
This is gripped by a clamping vice mounted on the cnc machine base.
Correctly set up, the frame plus work, can be turned over in the vice, and registration for the second side will line up with the first.
John