Low quantity run engineering solutions?

[T i m]

Hi all,

Does anyone have personable experience of a 'small engineering Co' who might be able to produce a small (maybe 200 or so) stainless steel (M3-4) internally threaded 'inserts / spacers' at a reasonable price please?

I could do 'a few' myself (and might as a proof of concept) but I don't fancy doing a couple of hundred.

Cheers, T i m

p.s. I have some sample sleeve nuts on their way but it may be difficult to get such with the right head and in the right length, off_the_shelf. If I can find something suitable they will probably be quite expensive (50p+ each).

[dennis]

?

[T i m]

Oooh, thanks for that dennis ... and they may be able to do something, even though they don't seem to list exactly what I need:

Their smallest diameter (internal thread) is M5 looks like the closest (to M3-4 I think I need) but is 8mm OD (which is a bit big).

I'll drop them a line. ;-)

Cheers, T i m

[DavenPort]

Try this chap. He does small specialist component runs.

[T i m]

Thanks for that, they seem to offer the sort of services I was thinking of. I'll drop them a line. ;-)

Cheers, T i m

[unk]

Look into the rc model business, they use lots of m2/m3/m4 spacers.

Don't know about stainless, but they do do brass and ally...

[T i m]

Another good thought (thanks). I am a long term RC Modeller (inc RC / IC catamarans) so I know where you are coming from. [1]

Unfortunately this is for 'marine use' and so I feel it would have to be stainless and I'd be even less likely to get what I need in phosphor bronze (as I don't think 'brass' is recommended for marine use below the waterline).

Cheers, T i m

[1] Daughter bought me an RC Forklift for my 60th recently. Great fun. ;-)

[whisky-dave]

rapid do something like that at

[T i m]

Thanks for that Dave, you are right in that they are 'something like that', I don't think the actually do what I need.

This is for a 3m long, folding, marine ply and a heavy-duty PVC 'hinge' boat where the hinge is a strip of PVC glued to each side of the hull and a strip of marine ply glued and nailed though on top (making a ply-PVC-ply sandwich).

Now, one builder of said folding boats puts a 3/4" 'Gripfast' (ring-barbed) nail though the sandwich and then folds the top of the nail over and back into the surface of the ply like a staple. The builder of mine simply put the nail straight through (still possibly 'Gripfast') but just snipped it off. In some places the binding effect of the ply overstrip has become weak (and a couple of nails have pulled out) so I was looking for an alternative.

Whilst I could use the nail and staple technique, if you ever have to replace the hinges, digging the staple-nails out is a right PITA. So, I was thinking of getting the nail(s) out (one-at-a-time), drilling through with a close interference fit drill and pushing said threaded inserts though the 'sandwich' and using a flat / pan-head SS screw (either side) to nip it all up.

The spacer therefore doesn't need to be hex as the two screws would find a balance in the threaded insert between them and could be undone easily in the future, should it ever be required.

Cheers, T i m

[Andy Burns]

What about connector bolts? e.g.

[T i m]

Yes, they really would be perfect Andy, as long as they came in stainless steel, 3-4mm diameter thread and ~10mm internal length. ;-)

That's why I was trying to d-i-y (to some degree) the same sort of things but just with a simple threaded spacer and two conventional threaded pan / flat head screws [1] of some sort (that would be cheap and easy to locate with all sorts of different heads).

It's just getting ~300 of the 10mm long stainless steel threaded inserts that is the goal now I think.

Had they been a slightly bigger diameter (say 6mm) I might have done it in my lathe myself but drilling and tapping 3-4m threads in stainless isn't fun (I've done similar making bits for a 3d printer extruder hot-end).

Cheers, T i m

[1] The heads need to be as flat as possible for where the hull folds inwards.

[Adam Aglionby]

[Andy Burns]

Well, look around e.g.

they certainly have some that are M4, some that are stainless (perhaps brass would also suit a boat?), some that are flat head, some caps that are 10mm internal length, presumably cutting the bolts wouldn't be to tedious if necessary?

All you need to do is see if they do the right combination you're looking for :-)

[T i m]

I had. ;-(

One thing I had spotted on there was their stainless 'T-Nuts' :M4 x

8mm

Apparently not, well not when used under the waterline and in salt water.

No, that could be done but as we are talking ~300, I'd rather not. ;-(

And I don't think they do ... hence the suggestion of having something made.

It *has* to be stainless (I don't think a phosphor bronze M3 diameter thread would be strong enough, if such existed), can't be bigger in OD than the minimum required for an M3 worst case, M4 tapped hole (through said spacer) and to be able to secure a ~10mm sandwich.

You would think there would be loads of options out there but in spite of the best efforts of some good folk here, nothing has as yet been offered (especially off_the_peg) to suit.

That said, those M4 'T-Nuts' *could* be an option but they would have been better if they were a bit longer (so they went though most of the sandwich) or shorter (so they only went through one of the ply layers). Now, if they had done the M3 x 5 in stainless ... ;-)

Cheers, T i m

[T i m]

Assuming I've done the search correctly Adam,

CNC Lathing, United Kingdom, Stainless Steel ... No results. ;-(

Cheers, T i m

[Andy Burns]

Any good?

[T i m]

I'll let you know when the samples they said they'd send the other day arrive. ;-)

However, whilst an unslotted sleeve-nut may well be ok whilst initially being tightened (subject to a clean thread and a reasonable nut-fit in the hole in the ply), I'm not sure how easy it would be to remove if / when required (and sort of part of the remit or I just use Gripfast nails and bend the tips over).

Thank you very much for your continuing quest on my behalf though Andy! ;-)

Cheers, T i m

[Adam Aglionby]

hmmm, cnc lathing in stainless seems to be NA anywhere including China and US.

fabhub not as well subscribed as 3dhubs.com which is exclusively 3D printing though possible to get metals done that way, would a tough printed plastic part work in your ap?

There is also

and both mycncuk.com and cnczone.com have RFQ sections.

[T i m]

Interesting. I tried to go for a basic written quote but got to:

"IMPORTANT: Size must be in INCHES and must be accurate."

How quaint the Yanks are. ;-)

They look more likely, I'll check them out later (thanks).

(Going to try to clean some dinghy sails while the sun is out). ;-)

Cheers, T i m