Machining LG struts from 3/16 to 5/32"...#*!%!?

Wingnutz · May 26, 2013, 01:31:57 PM

Hoping someone has experience as a machinist or hobbyist with a lathe and knows someting about machining a 3/16"(5mm?) LG strut down to 5/32" (4mm?). Tried on a hobby lathe and the LG stock is really hard to the point it's difficult to get a smooth cut. The shaft bends as the cut gets farther from the lathe chuck further complicating the whole thing.
Please don't ask why I don't just get a thinner LG strut and I promise not to bore you with my usual long winded explanations.

Ededge2002 · May 26, 2013, 04:37:00 PM

I've got to ask..

To turn down hardened wire is going to be tough. To do it properly you would use a grinder mounted on the lathe or at minimum a dead centering pin on the unsupported end.

sihinch · May 26, 2013, 05:28:30 PM

Why don't you just get a thinner strut???

I have some 4mm hardened steel pins, if they would help? Approx 30mm long.

Wingnutz · May 27, 2013, 11:39:00 PM

Okay you guys had to ask! The LG strut(s) I'm trying to machine is/are part of a Fults double strut nose gear. It's like a tiny bicycle fork with a 3/16" stem which I want to put into an eflite retract which has a 5/32" hole in the trunion.
I'm trying to do this to create LG that at least resembles the double oleo strut LG on a Mosquito and is capable of carrying a 3" wheel.
There! Aren't you glad you asked!

Ededge2002 · May 28, 2013, 08:06:49 AM

Pictures. I need pictures.

Yep I'm a pain

Wingnutz · May 28, 2013, 09:18:10 AM

We're working on the RF 400 size without the supplied mounting brackets...the stem (single strut above the spring) is 3/16" dia. Hole in my retract trunion is 5/32".

piker · May 28, 2013, 10:15:05 AM

Why don't you drill out the hole?

Wingnutz · May 28, 2013, 10:24:51 AM

Rob,
The reason I haven't done just that is I'm concerned drilling out the trunion will compromise its strength. Are my fears unwarranted?

Bobmic · May 28, 2013, 11:08:59 AM

The difference is only 0.8mm in diameter check how much room you have in the retract I doubt you'll have a problem.
How did you plan to mount it in a lathe?
If you are able to spin it some how, use a grinder or just sand paper which will take a while but will probably end up with the best result.
... I would drill it..

Ededge2002 · May 28, 2013, 12:11:16 PM

Actually its only 0.4mm you need to take off one side.....

I wouldn't worry about the other side...

Spinning in a lathe with a file this would take minutes.

piker · May 28, 2013, 12:20:56 PM

I don't know what you guys are talking about... it's only .016" per side

I can't judge whether the gear has the required material without seeing it, but I would rather take a little material from a block of whatever, then thin down the strut. The top end of the strut, where it enters the retract, is the highest stress area and the place where failure is likely to happen... especially if thinned down with reworking of the spring steel wire.

Robert