downtube thick

[Marchrider]

these tubes are made to be 'just strong enough' the thinnest material possible to save weight - drilling anything through it will create a weakness, and that weakness could be just too much - and remember aluminium can fail catastrophically
far better to make some sort of strap to go around the frame, 3d print something. far safer

 

[alrzaln]

No, I mean the top of the downtube. What has happened is that the lower vertebra has disappeared and its hole has widened. I have restrained it with a belt. Due to the widening of the hole, it is not possible to install the m5 size revnut. But with my research I found that Plusnut is a better option.

I assume you mean under the down tube ? i would be looking at a strap on model to save the potential problems
https://www.sjscycles.co.uk/bottles-cages/sks-anywhere-bottle-cage-adapter/
https://www.bike-discount.de/en/ibera-strap-on-bottle-cage-mount

 

[alrzaln]

these tubes are made to be 'just strong enough' the thinnest material possible to save weight - drilling anything through it will create a weakness, and that weakness could be just too much - and remember aluminium can fail catastrophically
far better to make some sort of strap to go around the frame, 3d print something. far safer

You made a good point. ofcourse, I do not intend to create a new hole. But I want to use the main hole that has been widened. I have already restrained it with a strap. Maybe this will suffice.

 

[Yellow Saddle]

If you really want to know the thickness of the tubes and don't want to cut them up to find out then you'll need an ultrasonic thickness gauge. You can buy them on Amazon but I have no idea how accurate they are as I've never used one.

Alternatively, one of my ex-employers make a tube wall thickness gauge that used Gamma rays from a 10 Curie Caesium 137 source shrouded in depleted Uranium and Lead. I can vouch for the fact that is very accurate but it's rather expensive at around £500,000 and you'd have to be prepared to wait about 2 years for them to deliver one - 10Ci Cs137 pellets are rarer than rocking horse manure. Then there's the issues of licensing its use, somewhere safe to install it, a certified Radiological Protection Advisor to okay the installation, etc, etc, etc, ... the problems are endless. Personally I'd go for the Amazon special

As a tool geek, I seriously question your conclusion.

 

[Drago]

these tubes are made to be 'just strong enough' the thinnest material possible to save weight - drilling anything through it will create a weakness, and that weakness could be just too much...

Yes that's exactly what many manufacturers do in order to provide mounting bosses on alloy frames.

 

[Bristolian]

As a tool geek, I seriously question your conclusion.

Well, if you've got half a million to spend waste then I'll put you in contact with a company that would be only too willing to relieve you of it

Seriously though, I wasn't conscious of forming a conclusion.

 

[Yellow Saddle]

Well, if you've got half a million to spend waste then I'll put you in contact with a company that would be only too willing to relieve you of it

Seriously though, I wasn't conscious of forming a conclusion.

Good tools have a price. Why go for an Amazon gadget when you can have a plutonium-fired, laser-guided thickness gauge? Quality and accuracy is remembered long after the price is forgotten, or something like that.

 

[Hover Fly]

…Personally I'd go for the Amazon special

Which, possibly, won’t go thin enough, unless you spend £1000 plus. Simple method; flick it with a finger nail and go by the ring and feel.

 

[biggs682]

Drill a hole and measure the thickness