How do you turn a woodscrew?????

I need some giant double ended wood screws of maybe 10mm or 12mm diameter by 100mm long. (or bigger)
(fixing 5"x5" timber baulks upright to 10" x 5" oak railway sleepers
to form a handrail over a bridge). So far I've failed to find a supplier so may have to make them..
So how the heck do you cut a tapered woodscrew thread on a screwcutting lathe???
AWEM
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On Sat, 14 May 2011 22:29:09 +0100, "Andrew Mawson"

Depending on the lathe, you can do screw cutting combined with a taper turning attachment. This only gives you a cone shape for the minor diameter, but that can work. Do the major diameter parallel with a taper to the point.
Mark Rand RTFM
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    --Try a chandlery; if you can make do with wood screw on one end and a machine screw on the other these are common.
--
"Steamboat Ed" Haas : Steel, Stainless, Titanium:
Hacking the Trailing Edge! : Guaranteed Uncertified Welding!
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On May 14, 5:29 pm, "Andrew Mawson"

If you predrill the holes the screw doesn't need a sharp point. You can turn them between centers and just step the end down with shorter and shorter cuts, then file smooth.
IIRC I used my vee-belt pulley bit and stopped each pass 0.020" shy of the previous one to get a starting taper.
jsw
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You could use M12/12mm Dowel screws, cut the M12 down to about 12" long and use a studding connector to join two together. A short counterbore will accomodate the stud connector.
http://www.a2a4.com/acatalog/M12_DOWEL_SCREWS_A_2.html
http://www.a2a4.com/acatalog/copy_of_STUDDING_CONNECTORS_HEX_NUTS_3D_A2.html
Or do it properly with a pegged mortice & tennon joint;)
J
--
jasonballamy
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Get some suitably sized coach screws, cut the heads off and weld them together. www.tikproducts.co.uk sell coach screws up to 20mm dia. x 300mm long
Bob
On 14 May, 22:29, "Andrew Mawson"

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Dunno but why don't you just fix them with angle brackets and normal length screws?
--
Dave Baker



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That would solve the small matter of how to screw in the second one, too. Do you rotate the handrail or the bridge?
jsw
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On Wed, 18 May 2011 09:38:00 -0700, Jim Wilkins wrote:

That would work for the first screw but what about the rest,
--
Neil
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On Fri, 20 May 2011 10:07:19 -0500, Neil Ellwood
*shrug*
    Maybe Andrew doesn't NEED a rest after his first screw? --
Chris Edwards (in deepest Dorset) "There *must* be an easier way!"
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wrote:

jsw
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wrote>

sleepers
length
That would solve the small matter of how to screw in the second one, too. Do you rotate the handrail or the bridge?
jsw
Handrail fairly obviously will be fitted when all uprights have been planted. This brdge is 6 metres long and is slightly arched (3 metre radius iirc) So the handrail will be several 5" x1" planks laminated as they are fitted, and held down into the curve as the glue sets. When firmley glued it will be carved/ planed / routed to a smooth shape
AWEM
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wrote>

Seems unlikely as that makes it a semicircle that hardly fits the slightly arched description!

Now that coupled with the above dimensions calls for steaming them before bending. On balance I reckon the radius of curvature is wrong. Should it be 30 metres radius? Henry
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wrote>

normal
one,
been
metre
slightly
before
You may well be right. The 'hump' is about 18" over the full length. By the time the uprights are planted on it the radius will be even gentler and I don't anticipate issues bending the planks if I can get them in full lengths.
AWEM
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On May 22, 1:57 pm, "Andrew Mawson"

Around here the big-box home improvement stores sell them pre-bent to that shape.
jsw
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sleepers
length
'cos it would look tacky !!!
AWEM
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<Big snip>
Use a taper turning attachment!
Steve R.
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With a screwdriver!
Chris
PS. Yeah, I know but it's been wanting to be said for quite a few days now.
--
Chris Eilbeck

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What does a screwdriver for double-ended screws look like?
A double-ended screw with the center knurled, probably not what's needed here: https://picasaweb.google.com/KB1DAL/Tools#5168765927027495682
jsw
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