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Gland nut threads

Posted: 17 Jun 2013 06:28
by datzenmike
Anyone know the thread or tap size for the strut tube. Or anything about the gland nut threads??

Re: Gland nut threads

Posted: 17 Jun 2013 07:38
by Dave Patten
"The thread is an M48X1.5"

per Byron510.
He re-taps his struts when he shortens them, no cut & weld for this boy and owns the M48x1.5 tap.

Re: Gland nut threads

Posted: 17 Jun 2013 08:38
by S15DET
ebay has that tap for $130 (chinese).

Re: Gland nut threads

Posted: 17 Jun 2013 12:29
by RedBanner
Thanks guys, and thanks mike for reposting here. Woot woot.

Re: Gland nut threads

Posted: 17 Jun 2013 12:39
by datzenmike
Well where do the experts go when they don't know? To the Realm.

Re: Gland nut threads

Posted: 18 Jun 2013 11:51
by Byron510
Dave Patten wrote:"The thread is an M48X1.5"

per Byron510.
He re-taps his struts when he shortens them, no cut & weld for this boy and owns the M48x1.5 tap.
Actually, I have to make a correction here - I don't own this tap, but it would be nice.

Most of the story...

I set the strut up in a lathe, bore the tune to size and cut the thread manually. Aside from cutting the thread, the inside bore does need to be machined out as it is too small. Also there should be a radius cut in the bottom of the thread for strength reasons - as with any thread that's internal or external. It's just good engineering.

Byron

Re: Gland nut threads

Posted: 18 Jun 2013 18:23
by datzenmike
Bjorn in Norway sent me these last night. Tapped an extra 20mm and cut off the extra so that zx inserts fit a European 810 tube.



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Re: Gland nut threads

Posted: 18 Jun 2013 22:44
by McWicked
Bjorn must be a god with a hacksaw. If I tried cutting a strut tube by hand... I'd end up with a cut about as straight as Richard Simmons.

-McWicked

Re: Gland nut threads

Posted: 19 Jun 2013 05:11
by butters68
oh mcwicked you silly. :P

Re: Gland nut threads

Posted: 22 Jun 2013 23:08
by goichi1
McWicked wrote:Bjorn must be a god with a hacksaw. If I tried cutting a strut tube by hand... I'd end up with a cut about as straight as Richard Simmons.

-McWicked
I know that's right, there is no way I could cut that straight either, it's even hard in the horizontal band saw.

Re: Gland nut threads

Posted: 13 Nov 2013 09:44
by driverwagon
Sorry for the thread bump but I am getting ready to do this strut swap project. From reading the threads I would prefer to cut and tap than cut and reweld. Byron you mentioned that you need to bore the strut tube out. Does the strut tube taper down or is the material thicker? How much do you bore it out? Also pardon my ignorance but what is the radius cut that needs to be performed at the bottom of the threads?

Thanks

Dave

Re: Gland nut threads

Posted: 13 Nov 2013 20:22
by Byron510
Hi Dave, perfectly valid questions.
The bore of the tube is simply smaller than the I'D of the threaded area at the top. These are bored out before threading at the factory.

I'd like to know how much force was needed in the above post to machine and thread out that tube? Or maybe even that specific tube has a larger bore for the original strut.

To get you right bore diameter, you need to take (for a 60 degree thread) one pitch size off the major (outside) diameter. So in this case 48-1.5=46.5mm. If memory serves me correctly, the bore is 44mm. But my memory isn't all that reliable all the time. Just measure the bore of what you have and turn it out to 46.5+0.1mm for a little clearance before threading with a tap or a single point tool.

Byron

Re: Gland nut threads

Posted: 15 Nov 2013 08:45
by driverwagon
Awesome thank you.

Re: Gland nut threads

Posted: 24 Nov 2013 22:50
by Byron510
Dave,

I shortened another set of struts today, and took note of the ID dimensions for you - and all others to read. The bore of the PL510 strut is 45.2mm. The minor diameter of the M48X1.5 thread is about 46.7mm. So if one was to push a tap through the strut, you'd have to essentially push through about 1.5mm or 0.060" of bore from the steel tube which would take a lot of force (read – leverage!).
I'm sure you can do this (push a tap through without boring the ID first), but taps really don't like to do this operation. I suspect you would end up tearing the thread surface, especially the crest of the thread. Pushing that much material off might cause galling, and in the end a poor thread form, with little strength. Maybe not - is there someone out there on the realm who has actually just pushed a tap through the a hole that’s too small on this scale or size? Maybe share your experiences and photos of the finished product.

In the mean time, I have included below photos of the counter bore inside the strut tube, and the finished thread cut with a single point tool.
BTW - Mike, your struts are ready to go my friend :-)

Byron