Thread: Left Hand Thread

I have bought LH thread Booker rod (with nuts) from a specialist nut & bolt supplier, had to order it in though. I don't think it was 12mm, more like 8mm and in mild steel not stainless...so quite useless information really!
You may be better off just getting a length made to suit at an engineering works, on a lathe.

Good luck,

artme

Have you priced LH dies and taps from E & J Winter? I find they are much cheaper than other sources for P&N stuff.

Does it have to be LH thread ?

The idea is good, but your choice of steel for your thread isn't. Don't use stainless steel for a vice thread, it will bind up in the nut as soon as it comes under pressure. I use a lot of ss fixings for canopies and tool boxes where I work and you need to be very liberal with oil even on the first tighten.

I would buy commercial threaded rod, but even that I think would let you down. It's just not designed for that application. You could get some high tensile rod theaded at an engineering works that would be better, or you could source some acme rod that would do the job just fine. It would probably cost same as the LH dies to do the ss rod.

Just my thoughts

Robert

Art, Now I know what you are doing I agree with specialist that the SS will bind. You could use SS thread and a bronze nut but SS is generally too soft for that sort of thing and conventional threads and vices are not a good mix. Maybe you can find someone to cut a square cross section thread for you on a lathe?

Looks like I've got problems no matter which way I turn. Pardon the pun!
Because I want the vise jaws to be self centering I need to have LH thread on one end and RH on the other.
I take the point about 304SS being unsuitable for the job. but an Acme thread is going to be so expensive as to make the project unworthwhile.

The vise is to be used to hold pen blanks for drilling so there will not be a need for a thread that takes huge amounts of stress. I've come to the conclusion that mild steel will probably be OK but high tensile would be better. I've done some research and can get HT, LH threaded rod for about $20 metre. If I can get a foot that will only be $7. A similar quantity and price for Rh and I'm on top.

Two problems:

• joining LH & RH halves so they are in perfect allignment
• obtaining LH nuts.

Any advice appreciated. Thanx.

Art, There's no doubt about it - you are persistent - I'm impressed

What you want is that piece of rod where they changed from making the LHT to RHT and you'd be sweet on the first issue.
The second issue puts you back at the start.

This is where having a big pile of mechanical junk to paw over has a small advantage. Don't get excited I have looked over it already but the best I can say is I will keep my eyes open if you want.

What about a small clapped out grinder - someone must have one in a shed somewhere - they have left and right threads and respective nuts as well!!!

Originally Posted by artme

Looks like I've got problems no matter which way I turn. Pardon the pun!
Because I want the vise jaws to be self centering I need to have LH thread on one end and RH on the other.
I take the point about 304SS being unsuitable for the job. but an Acme thread is going to be so expensive as to make the project unworthwhile.

The vise is to be used to hold pen blanks for drilling so there will not be a need for a thread that takes huge amounts of stress. I've come to the conclusion that mild steel will probably be OK but high tensile would be better. I've done some research and can get HT, LH threaded rod for about $20 metre. If I can get a foot that will only be $7. A similar quantity and price for Rh and I'm on top.

Two problems:

• joining LH & RH halves so they are in perfect allignment
• obtaining LH nuts.

Any advice appreciated. Thanx.

You'll need a thickened portion between the LH and RH rods to maintain the centre anyway, so I'd suggest welding both rods to a disk. The rods can be fixed in alignment on your lathe with a turning chuck at the headstock and a Jacobs chuck in the tailstock, and the disk held in position for welding by tailstock pressure. Perfect alignment might not be as necessary as it seems. Many years ago, I made an internal turnbuckle from parts of a conventional turnbuckle, by a less precise process. I cut the turnbuckle body for my source of LH and RH "nuts." The whole contraption was encased in resin castings, so wrench access wasn't needed. BTW, the device was a mirrored stereo viewer with adjustable interpupillary distance.

For other LH nuts, consider a drill arbor as used for wire wheels. They're usually LH thread, and the kit should be available at any tool supplier. Limited sizes available, though; here, they're usually 1/2-20 UNF, possibly similar metric in your neck of the woods. Keep the nuts, and bin the rest; or save for restoration if you're a pack rat like me.

Is this the same device in a similar recent thread? A cartoon of your design might solicit more creative suggestions.

SS fasteners are indeed subject to "galling," as it's called. Less so if the nut and bolt are of different SS alloys.

Joe

Artme,
try Melbourne Bolt Co.
http://www.hotfrog.com.au/Companies/...Bolt-Co_176585

I purchased LH nuts and lock nuts from them a few years ago.
As I was only after a few, they had one of the local shops make them to order.
I used them for lock nuts on adjustable tie rod ends for trailing arms in a suspension setup.

They are worth a call

Many years ago, I had a similar problem. I ended up threading the rod with one end fine and the other coarse thread, both RH. It got the job done but was obviously slow. Wayne.

Well I had the same problem a few years ago.
Solution, well got 2 car jacks (scissor type) exactly the same, nice threads, have nut, good for vices.
Now, mount them side by side, attatch cogs at one end, so they both drive in different directions. Attatch a fence to either one. use 2 rods as guides/bearings for the fences. Bingo, a self-centering vice.

Slowly getting My bits and pieces together.
Found some M12 Turnbuckles to-day. Each threaded section is a good length. I'll have to weld them together with a mates TIG.
Will need to buy nuts and I have located these.
Last parts will be 2 gear wheels and a knob or crank handle. On the track of that tomorrow.

Loved you car jack idea Spoinky but even the smallest I coul get woul be too cumbersome for my purpose. Great "outside the square" thinkinking though!

By the time I get this done I hope to have learnt how to post photos so that you can see the cuase of my agony.

Artme,

How about knocking up a rough free hand sketch, scan it or take a digital image, and submit it so we all know exactly what you are trying to achieve.

A picture is worth a thousand words, etc.

Ken

Went to the tip today and bought 2 small wheels coomplete with tyres and tubes and the parts I was really interested in, The sprockets for back Pedal brakes. I'm only short by a length of bike chain now.
Cost $6.00 frothe pair. Total Bill to date for parts is $20.35.