Best way to keep nuts tight (ha ha)

Hi Guys,

I am attempting to make an approximate depth upper and lower depth indicator for my Sherline mill to ease repetetive jobs where precision need only be approximate.

There are several ideas I have come up with but as always all have their pros and cons. I have settled on a simple M10 stud bar that I can clamp next to the z axis ans this has 2 6mm mild steel bars that can be used to either point or provide limit if when tested it is firm enough.

However vibration could / will loosen m10 nuts so I am trying to decide the best way of once I do up the nuts to mark a position they stay there.

Options as I see it are double nuts acting as locking nuts, spring washers between nut and 6mmm pointer, nylocs? I in all honesty do not know which is likely to give better results....your help please?

Chris

You can also use a 'squashed' nut where the thread is slightly oval as used on Chevy V8 since 1955 through till the 1980's and the Vauxhall HA Viva rockers nuts

Update I have just come across Nord Lock washers they go on in pairs. They work by maintaining friction whereas other washers and Nylocs apparently lose friction under vibration.

Anyone got any experience of these Nord Lock washers?

Chris

There is a reason why good old fashioned machines/engineers use fine threads. 😁

Edited By Adrian Downes on 03/09/2020 15:16:28

Do they stand repeated use?

That said the tumble reverse lever on my 5" lathe is just an ordinary single nut and that stays put

How about drilling / tapping say M3 / M4 in one side of both nuts, insert a nylon plug & then screw in a M3/4 grub screw & tighten as required to hold nuts in place ...

George.

Well Adrian I just looked it up and some of the pros of fine threads is less tendency to loosen, they give finer adjustment and most surprisingly for me they are stronger than a coarse thread bolt. Deficits obviously harder to find, more prone galling and I have no tap for such a finer thread yet. But i note this for future reference in case the M10 proves inadequate for approximation.

Chris

Unless you tap loads of grubscrew holes or have free access all round the stud bar, Sod's Law will place the grubscrew just where you can't get at it when the setting's right...

Edited By Mick B1 on 03/09/2020 16:16:36

Do you really need M10 on something as small as a Sherline?

Swapping to M6 would be more in proportion with the machine, and instantly gives you a 1mm pitch instead of the 1.5mm you currently have

You don't need to get at the grub screw all the time, it is just used to set a level of friction, may need the odd tweak as the slug of nylon takes on the form of the thread, think of it as an adjustable Nyloc.

Two tappings 180* apart would provide enough access for adjustment.

George.

What about using nyloc nuts the friction from the nylon insert should stop them moving but still allow easy spanner adjustment. Cheap as chips and easily replaced if they do start to move by themselves

I use Blu-tak.

Rik

If you fancy a bit of interesting work, why not make a pair of Tilt Nuts? When you tilt them they can be moved freely along a threaded rod, but act like ordinary nuts when not tilted. A pair can be locked together like normal locknuts.

Here's something new to me, one for my notes as the trouble is as many of you guys will know that you can never have enough tools and sometimes it may be a case of focusing on the objective and trying as best one can not to be diverted. something I fail at miserably...but hey still fun.

Chris

I would try Hardlock nuts, which operate on a wedge principle. I came across them at a trade show early this year and and was given a couple as samples. I have used one, and was most impressed with it. Unlike such things as nyloc nuts, it doesn't lose its grip with repeated use.

https://www.hard-lock.co.uk/

Usual disclaimers,

George B.

I would use an M6 nut and M6 studding in a threaded hole. If that comes loose I would be more worried about why my milling technique was causing that much vibration.

Neil

The quill stop on my TOS just used 2 "nuts", which you lock together using finger pressure.

They are about 1" diameter and knurled, not plain hex nuts.

Dave

hi, i have a box of nord lock washers and find them very good. you dont need to tighten to much or you risk flattening the serrations, they can be used several times. when they came on the market i got a free bottle opener with a wing nut on it, the idea was you very gently tightened the wing nut with your fingers and it was impossible to slacken it without a pliers.

I am assuming that you may want to adjust the nuts regularly so any friction solution will make it very tedious to move any distance. Two nuts locked together and nipped up with a spanner are probably going to stay put, if they don’t then a plan B will be needed, I would try the simple first and see how it goes.

Mike