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ticklingmedusa
30th August 2006, 05:12 PM
I live in Southern California and in just over two years of spinning wood I have tried a fair number of exotic timbers. I'm extremely fortunate to have a fairly large variety of species and number of exotic wood dealers in my area.

Katalox or Swartzia cubensis could be one of the hardest most dense materials I've ever worked with... .I know you turners down under are accustomed to hard timbers and I've worked with a few from oz but this is almost like stone.

Try the link for a factsheet & images http://www.hobbithouseinc.com/personal/woodpics/katalox.htm

Because I have some problems with my hands I use a 4 screw faceplate instead of single screw chuck to initially mount my bandsaw-rounded blanks and rough turn and then shape a tenon for reverse chucking into a talon 4 jaw scroll chuck.

I drilled pilot holes into my Katalox blank and used a 1 1/2 inch wood screw and broke a couple of the screwheads off with my cordless drill and #3 phillips bit.

After a few choice expletives I realized one mistake I made ( and should have known better ) was using screws that were previously used.

Metal fatigue.

A dab of beeswax is something my grandfather used and something I should have remembered to use.

I'm trying to figure out what else I might do when I retry screwing on the faceplate.

Maybe I should just glue a wasteblock on.

I'm still stuck with the problem of extracting the broken off shanks of the screws.

The Katalox was touted as an economical substitute for ebony... but time wasted and wear and tear on hardware and yours truly kind of balances things out in the long run.

Thanks for any ideas,

tm

Don Nethercott
30th August 2006, 05:28 PM
Hi ticklingmedusa,
I always use 4 screws on the faceplate to turn my blanks. However I never use wood screws, I use selftappers. Of course these vary in quality - go to a tradesmans supplier and get really good quality screws. The screws I use are usually only 25mm (1 inch) and I've never had a screw break of or lost a blank,

Pre drilling would help with very tough wood, but don't make the hole too big so the screw could come loose.

We have a wood here called Gidgee. Hard as nails and just as rough on the tools. Often get it as old fenceposts - so hard even the termites won't touch it.


When I turn I do the bottom first, right up to sanding and poliching. Cut a recess in the bottom so I can turn it around and mount in the check then do the inside.

Have fun
Don

Auzzie turner
30th August 2006, 05:37 PM
Where can you get that timber?

rsser
30th August 2006, 05:41 PM
If the screws are big enough you can drill into the broken shank and use what we call an 'Ezy-out' to insert and get a grip on for removal. Otherwise try and core the centre out with a good parting tool, or of course a bowl saver if you have one.

I'm a fan of Robertson screws for this kind of work - square socket head things. Last for ever. Draw each through your hair (if you have any left!) for a bit of lube if you're worried about removal - but the ones I buy are coated anyway.

ticklingmedusa
30th August 2006, 05:53 PM
Where can you get that timber?

Joash, try sending my friend Mitch Talcove an email, he may know of someone in your area that can get it.

http://www.anexotichardwood.com/turning.html

If that fails send me a pm.
tm

Skew ChiDAMN!!
30th August 2006, 05:53 PM
Extracting sheared screws... one of my favourite jobs. Ha! :rolleyes:

Assuming the screws are in wood that'll be removed and you simply don't want to hit 'em with your tools (they're in the innards of the bowl for example) I'll drill 'em out with a 10mm drillbit. First I drill a pilot hole with a small bit, centred 5mm away from the edge of the screw, then use the 10mm bit. A hammer & punch is then used to tap the broken screw over into the 'ole, where a pair of pliers will easily yank it.

If space is more of a problem, I'll sometimes use the same bit I used to drill a pilot for the screw in the firstplace, drilling 3 holes equally spaced around the screw and hard up against it. Then a pair of needle-nosed pliers.

When even that causes too much damage (eg. for a hinge that covers sweet FA of the timber) then things start getting interesting. I resort to the ol' paring chisel to shave away enough timber to expose the shank and a damned good pair of vice-grips. Of course, as often as not this means needing to resand the surface to hide signs of extraction, but at least the wood can be salvaged instead of being replaced for the job at hand.

ticklingmedusa
30th August 2006, 06:05 PM
If the screws are big enough you can drill into the broken shank and use what we call an 'Ezy-out' to insert and get a grip on for removal. Otherwise try and core the centre out with a good parting tool, or of course a bowl saver if you have one.



This is what I'm looking for Ern.
I was wondering about the possibility of coring very carefully with a parting tool.
I don't have the bowl saver, maybe someday, they are a pricey item.



I'm a fan of Robertson screws for this kind of work - square socket head things. Last for ever. Draw each through your hair (if you have any left!) for a bit of lube if you're worried about removal - but the ones I buy are coated anyway.

I chose the phillips because they were thicker than the Robertsons I have on hand.
I have a little hair left but I need a hat in the hot sun.:cool:
Thanks mate.
tm

ticklingmedusa
30th August 2006, 06:09 PM
Extracting sheared screws... one of my favourite jobs. Ha! :rolleyes:

Assuming the screws are in wood that'll be removed and you simply don't want to hit 'em with your tools (they're in the innards of the bowl for example) I'll drill 'em out with a 10mm drillbit. First I drill a pilot hole with a small bit, centred 5mm away from the edge of the screw, then use the 10mm bit. A hammer & punch is then used to tap the broken screw over into the 'ole, where a pair of pliers will easily yank it.

If space is more of a problem, I'll sometimes use the same bit I used to drill a pilot for the screw in the firstplace, drilling 3 holes equally spaced around the screw and hard up against it. Then a pair of needle-nosed pliers.

When even that causes too much damage (eg. for a hinge that covers sweet FA of the timber) then things start getting interesting. I resort to the ol' paring chisel to shave away enough timber to expose the shank and a damned good pair of vice-grips. Of course, as often as not this means needing to resand the surface to hide signs of extraction, but at least the wood can be salvaged instead of being replaced for the job at hand.

Thanks Skew,
after reading yours I feel like Ive been to a dentist.
tm

Skew ChiDAMN!!
30th August 2006, 06:22 PM
You've seen my dentist at work, eh? "When all else fails, get a bigger pair of pliers."

I'd love to have a good bowlsaver, but even if I had one I don't think I'd risk using one in your scenario; the saver tips aren't cheap and if you do manage to find the end of the screw, well... chipping the tip would be the least of the nasty possibilities. [shudder]

You could always use a parting tool to turn a trench each side of the recalcitrant screw and simply "break off" the segment of wood with the screw in it. It'd reduce the risk to your tool (and toolrest and fingers) but is too much faffing around for me.

ticklingmedusa
30th August 2006, 07:59 PM
You could always use a parting tool to turn a trench each side of the recalcitrant screw and simply "break off" the segment of wood with the screw in it. It'd reduce the risk to your tool (and toolrest and fingers) but is too much faffing around for me.

This is more like what I have in mind.
Thanks to all for your replies.
tm

soundman
30th August 2006, 10:58 PM
A great thing for removing screws is a "rolled pin". these are those pins that are used to locate things on shafts & the like. They are a tubular item with a split down the length made by rolling up a but of spring steel.
anyway
get one of these from your fastener shop or engineering supplier, grind the end so it has a sort of drill tip.
then you can slip it over the broken screw and drill a hollow hole arround the screw and pull it out by your method of choice.

next time consider drilling & tapping the blank:D and use small high tensile bolts. no I'm not kidding.

or just drill a larger pilot hole.

cheers

TTIT
30th August 2006, 11:27 PM
A good trick for exposing the upper part of the screw as Skew does is to use a plug cutter, preferably a cheap one in case you hit the screw. Cuts a nice clean hole around the screw leaving enough room for the vice grips. (Of course I've never actually had to do this!!! :o:o)

rsser
31st August 2006, 11:31 AM
Just as a btw on bowlsavers, they may need a min height btwn top of banjo and lathe centre.

I looked at the Kelton gate but it was about a cm too high on the old Vicmarc 175.

Hickory
31st August 2006, 03:25 PM
I made a "Screw extractor" from a piece of 1/4" steel fuel line. a 2-3" section, file teeth around the edge of the tube, like saw teeth, BUT... backward.... Chuck the tube in a drill in reverse and set the home made hollow hole saw over the broken screw. saw a plug with the screw in center till you remove the stub. What is left is a 1/4" hole which you can plug with a 1/4" dowel or something tyou turned to plug the hole. The reason for backward is often the screw will back out with the cutting a prevent having to drill so deep.

TTIT
31st August 2006, 06:06 PM
I made a "Screw extractor" from a piece of 1/4" steel fuel line. a 2-3" section, file teeth around the edge of the tube, like saw teeth, BUT... backward.... Chuck the tube in a drill in reverse and set the home made hollow hole saw over the broken screw. saw a plug with the screw in center till you remove the stub. What is left is a 1/4" hole which you can plug with a 1/4" dowel or something tyou turned to plug the hole. The reason for backward is often the screw will back out with the cutting a prevent having to drill so deep.

Good one Hickory - I like that idea! :D Now where can I get some pretty tough fuel line though...