Modifying tie bar length
 

Does anyone know for sure that a tie bar that is too long can be easily shortened to a new length? Have you had it done or know someone who has and how was it done.

I have a 34' that needs to be 32~32 1/2" and I am wondering if it's as simple as shortening the threaded male insert on the adjustable end? I know some serious blades would be required...I have cut stainless before and unless you have the right blade it's like trying to cut glass with a Q-Tip.

I'd be real nervous about removing that much material from the insert, but here's how to check-

Find/make a probe and figure out how much thread you have before the cut, subtract the length you'd like to remove and see how much remains. As a rule of thumb, 1 diameter of thread engagement is all that's needed when dealing with similar materials.

If your thread diameter is 5/8, and you only have 1/2" of thread engagement remaining I'd be looking to other options, preferably a machine shop.

Using that formula I make it...I have 2" of threaded insert and I need to remove an inch to give me what I need...that leaves me with 1" of insert of 3/4" diameter...which should more than suffice if your formula holds true. Not to question what you have presented ( I appreciate your response) but as Ronald Reagan said "Trust but verify". If your theory verifies we have a winner!!

In any case this is something I will hand over to a machine shop to make a clean cut.

Thanks for your input.

It's from the NASA Fastener Design manual. I was going to quote the page, but I'm having trouble finding it.

Sounds like some of the lab work we did in ME classes like "Static and Dynamics of materials". I remember some destructive testing we did in the lab that involved the Kip (thousands of kilograms that a fastener could withstand prior to failure) loading of fasteners.

Obviously if NASA has a manual of these values it is based on empirical research that they did...good call!!

I have made my own tiebar before... generally a threaded boss is welded to the end of of the tube at each end. only shortening it 2 inches or so, look at it and see if your cut comes in inside or outside of the weld. if your cut is inside the weld, chuck it up in a lathe and turn a cut down untill you kiss the boss and it should pop out. then Turn the tube or the boss untill its clean and weld it back in at the right length. If you have a good sized lathe and a tig it should take a half hour to do.

Cut 1/2 to 3/4" off each end. Easy with a lathe.

That's what I'd do, my Monarch loves jobs like that.

I need to take some pics of this deal and post them.

This is a solid SS Latham Tie Bar with swivel ends.

Pic No 1 is an over all view.

[IMG]http://i705.photobucket.com/albums/w...psca242e7b.jpg[/IMG]

Pic No 2 Shows the right end

[IMG]http://i705.photobucket.com/albums/w...ps5cd54040.jpg[/IMG]

Pic No 3 Shows the left end where the adjustment can be made.

[IMG]http://i705.photobucket.com/albums/w...ps01b72a75.jpg[/IMG]

The last pic shows the insert removed and the 1 1/2" depth of the female drilled/tapped into the bar.

[IMG]http://i705.photobucket.com/albums/w...ps72f45306.jpg[/IMG]

My plan is to cut I" from the threaded male end so the over all length will be 32 1/2" which is center to center of my prop shafts. This will leave 3/4" threaded in which I can then lock down with the lock nut. Note that the current over all dimension is 33 1/2" ~ 34" and the male bottoms out currently at 33 1/2".

I think this will work.

John, just bring it over and we will cut the bar down, drill and re-tap for you. Solid bar is no problem at all.

Gratis - you deserve a break