Thread: What metal do I need

According to this website http://www.aerobolt.com.au/Products/...serts.shtml#AL you can get rivnuts with a M3 insert.
and they also have the tools to suit as well http://www.aerobolt.com.au/Products/...l#toolsinserts

Hi guys
Think I will have to go with stainles due to the small amount of room inside the tube. I did a test today with a rivet and it unfortunatly filled up the tube with itself. If I just tap the stainless it will probably save a heap of problems....It woks out about $10-$15 per meter.

How about making a small collet that fits around the tube and is threaded and the screw goes through a hole drilled in the side of the aluminium or whatever tube you use. Does that make sense?. If you can't make a collet then perhaps rip the guts out of a large electrical connecter (brass may react with whatever metal you use though). The screw would be then in a solid piece of metal, the collet would be located by the fact that the screw goes through a hole in the tube and the wire in the tube would be pinched against the other side of the tube which in itself is supported by the collet. Simple!!

By the way they say that the 1.2mm zincalume sheeting woun't rust when cut because it has enough zinc in the coating to self heal over the very thin edge in the same way that anything that is galvanized does when it suffers minor damage.

Good luck

Bill

How about a collet that fits around the tube and has a threaded hole in it to take the screw. If you then drill a small hole in the side of the tube the screw will pass from the collet and through the wall of the tube and pinch the wire against the other wall which is supported in turn by the other side of the collet - if this makes sense. if you can't make a collet then rip the guts out of a large electrical connecter of the appropriate size - brass though so it may cause corrosion problems with the aluminium if in a damp situation.

By the way they say the 1.2mm zincalume sheeting won't corrode when cut because there is enough zinc in the sheet coating to 'self heal' over the thin cut edge in the same way that hot dipped galvanized metal will self heal over slight damage.

Good luck

Bill

My first post - wow baby...
Maybe you are a bit too young in that you believe salesmen or people who are trying to palm you off. Zinc alum. not rusting where it is cut/screwed etc. yeah...
The best way to get answers to problems is to photograph the idea/plan etc. & upload them to a place such as 'ImageShack' & then you can put 'thumbnails' or .url links to your pictures to explain what you need.
Personally I think that stainless steel is the way to go (unless you need heaps of it). If the area to be tapped is too weak then, as has been mentioned, a build up of metal (just silver solder a scrap to the area) is required. The main thing with using s/s is that you use sharp drills (about 30 degs.) & cutting tools. One day when you get around to using TIG you will find s/s is great to work with. btw marine grade alum. is quite strong - the normal grey rubbish is ultra weak.

kev

edit: billy - you get extra points fot double posting? he he

Kev,
I'm old and ugly enough that salespeople don't try to palm me off. Zincalume is "self healing". The coating will migrate to cover and protect cut edges or scratches. Obviously not suited to extreme applications like marine environments but it does work, I've seen it over the years and it is covered by a warranty. If you have information or evidence to the contrary please share it.

Mick

Originally Posted by journeyman Mick

Kev,
I'm old and ugly enough that salespeople don't try to palm me off. Zincalume is "self healing". The coating will migrate to cover and protect cut edges or scratches. Obviously not suited to extreme applications like marine environments but it does work, I've seen it over the years and it is covered by a warranty. If you have information or evidence to the contrary please share it.

Mick

Hi Mick,
Unfortunately I am much older & ugly than you - sales personnel either don't see me or run the other way...
I get what you mean about zincalume but I have spent most of my life in coastal areas. Even the copper ground rusted off my meter box one day... Plus a lot of my applications were for marine environments. Also, being an ex stainless & alloy fabricator, I have a soft spot for 316 grade stainless.
I did not intend to ruffle feathers so early on here - sorry.
My main reason for joining is that I would like to buy a lathe & mill for work & pleasure that I am about to do. I have well & truely lost touch in just what I should buy. I have spent about the last 20 years on being a computer um err expert instead of machining...
kev

Kevin,
no feathers really ruffled, welcome to the madhouse!

Mick

Hi, Im not really still to sure what your trying to achieve but have looked at your supplied photo. Small tube with large wall thickness is almost impsosible to find, rivnuts in an m3 may be available from the states but here in australia Ive never managed to get under an m6, also could imagine when you pull up an m3 it would rip destroy the tool installing it. Ive broken a few tool inserts pulling up m6's also for info an m6 needs a hole drilled 9.5 to fit the rivnut in. Best option would be to get some light weight gal tubing and weld a nut onto the outside so that way you have your strength for clamping down with, if the life span of the item is a few years then it really doesnt matter what you make it out of provided its not in a marine enviroment
Steve

Miles

The automotive industry uses steel tubing in small sizes for fuel lines etc. Also the hydraulic industry does.

You could perhaps try a truck spare parts place and buy a replacement fuel line or a hydraulic place.

Originally Posted by miles and jules

Hi ...Yeah we tried alluminim today(are there different grades of aluminium?)...but we need to tap it and put a screw in it and it just threads when we tighten it. So we are really after any mild steel-like tube that we can tap easily that doesnt rust and isnt copper.

It would be really great if we could get tube in this same zinc stuff we have in the sheeting.

These guys look like they have small sizes in stainless http://www.spec-net.com.au/links/link141.htm

For zinc coated steel tubing try a hydraulic supplier ,some of the hydraulic steel tubing is either zinc coated or cadmium plated.