Would a vernier caliper off amazon be sufficiently accurate?

(In Exeter, Devon) Need to get measurements of the head tube inner diameters for:

“…make an internal bottom headset, fitting a 51mm bearing with a special machined adapter. I already did something similar once. But I would need a precise measurement of the head tube inner diameter. The standard size is said to be 52.05-52.15; I would need a more precise measure. Because the adapter would be very thin walled… is basically an adapter to fit a 51mm bearing to the 52mm head tube, with the desired angle. I’d like to make it with 0.03-0.04mm interference fit so it doesn’t move but at the same time it can’t be too tight to compress the bearing or risk damaging the adapter (0.5mm) during installation…”

Considering what is being requested would an “amateur” level caliper (quoted generally as having accuracy +- 0.02mm bought online amazon/ebay) be up to the task of providing accurate enough measurements the guy is asking for or can anyone suggest a company/shop in Exeter where I could get the measurements done?

Digital? Have you tried Lidl or Aldi? My Lidl digital one is just as good as my mitutoyo verynear.

I’d take the frame/headtube into whoever is Making it that way they can measure what you have properly and have the mating part to ensure it works.

The only problem will be trying to get a decent interference fit with a 0.5 wall thickness.

Does someone like these guys not just have the right bearing to fit? Seems a complicated solution to whatever the problem is

https://www.ebay.co.uk/itm/BICYCLE-HEADSET-BEARINGS-1-1-1-8-1-1-4-1-5-8-1-1-2-36-45-45-45-45-90-/131855649871?_trksid=p2349624.m46890.l49292

And fwiw, yeah my aldi 7.99 caliper is as good as my mitutoyo at work

@cp

Its a custom “angleset” for a 2016/7 Canyon Spectral.

I know there are premade ones already available from certain companies but they have external headset cups for the bottom bearing which raises the head tube further increasing stack by 13mm and slackening seat angle and raising BB. I was looking at ways of slackening Head Angle without those other knock on effects from having the external cup

There’s always an error in measuring Inside Diameters with a caliper – it doesn’t matter if it’s digital or a real old school Vernier Caliper. The error is due to the thickness or width of the measuring anvils.

To do it properly you need an Inside Micrometer which would have convex anvils or you can use Inside Diameter Tool and then measure the result with a Caliper or an External Micrometer.

Aldi one here – very good.

Have you considered offset shock bushings? They’ll slacken the STA a bit but won’t raise the BB height or stack.

The operator is the least accurate thing with any digi vernier tbh, it’ll be fine though.

I’ve an Aldi/Lidl version which is exactly the same as the reassuringly expensive Halfords one, and exactly the same as the overpriced one I can order from work. All I can say is it takes very repeatable measurements so would appear accurate.

I never cease to be amazed at the efforts people go to with the aim of messing up the geometry of their bikes.

fruitbat

There’s always an error in measuring Inside Diameters with a caliper – it doesn’t matter if it’s digital or a real old school Vernier Caliper. The error is due to the thickness or width of the measuring anvils.

To do it properly you need an Inside Micrometer which would have convex anvils or you can use Inside Diameter Tool and then measure the result with a Caliper or an External Micrometer.

Never known an error outside the tolerance of the caliper using the internal jaws, unless they’re worn to buggery or damaged.

I’d say going for an interference fit on something with such a thin wall will just lead to it getting damaged when you try to install it. A sliding fit and a dab of Loctite will do.

Oh and if it doesn’t have a Vernier scale, it’s not a Vernier calliper!

Too thin a wall and no a micrometer is needed.

It’s basically a shim. Very odd question for someone if they claim to know about this stuff, unless I have missed something.

Never known an error outside the tolerance of the caliper using the internal jaws, unless they’re worn to buggery or damaged.

This picture shows the principle of how the error would be manifested (it may be small but it is there none the less 😊):

You won’t make any appreciable difference if I’m reading that correctly.

It sounds like you want to Make a 52mm OD/51mm ID tube ie 0.5mm average wall thickness. That is near as dammit impossible the thing will just fold up.

The “angle” of an angled headset comes from moving the bearing within the cups, lower forward and top back and then aligning them so the steerer can rotate along the axis.
If you reduced the thickness to zero at the front (properly not just theoretically impossible) you’d only achieve 0.5mm of offset with your setup. Hrdly worth the effort.

Just buy one off the shelf and fit a 10mm lower set of bars – same difference. It’ll save you time money and heartache.

This mon is extremely entertaining, I recommend you watch a few of his vids to understand why.

Callipers…

@cynic-al

I genuinely don’t know anything about this stuff. The quoted text was from the message I received from the guy who machines the headset cups. He’s saying he can get up to 2 degrees from the head tube

I’m not after 2 degrees, that would be a bit extreme for my bike. I’m just a little curious about this whole slacker thing and was interested to see how it would translate on my bike. If I didnt like it at least I’d now know I don’t like it. But don’t want to add other factors into it if it can be helped Ie seattube angles and BB height etc

He’s a gazillion miles away which is why wanted me to provide him the measurements he asked for

Then I recommend that you don’t use Aldi callipers to save money in the long run

What speeder says. The bearings need to be offset and/or angled in the cups to change the angle of the steerer relative to the headtube. You can’t do that with such a thin cup/shim.

b33k34
Full Member

I never cease to be amazed at the efforts people go to with the aim of messing up the geometry of their bikes.

You know how Trek developed the geometry of the Slash 29? They messed up a Remedy. Looked at what owners were doing to mess theirs up and copied it. Took a standard frame, went up a size, put an angleset and a shock bushing in it and a 160mm fork, and gave it to their team riders to test. Those numbers went straight into the first Slash proto as a result. And you can guarantee other manufacturers do the same.

I messed mine up the exact same way, what a fool :) Honestly I’ve had years of extra life and loads of extra pleasure out of bikes from making geo changes and never once regretted it. And the bike industry’s travelled the exact same route- everything is longer, lower, slacker, just like I always wanted to make my bikes. Just, we do it with cheap parts not new frames, now that’s messed up.

Yes and no…

My cheap Amazon one is accurate enough…when it works, which is about 20% of the time. The slide mechanism is awful so the caliper can slide without it registering on the dial

Aldi currently seem to have the calipers o sale.

Ultimately you want to measure sufficiently accurately to enable something to be machined to within 0.01mm accuracy (+-0.005mm if I understand your explanation properly)

I’d like to make it with 0.03-0.04mm interference fit

With a tool that’s accurate to 0.02mm

“amateur” level caliper (quoted generally as having accuracy +- 0.02mm

Yeah, good luck with that.

I have a cheapo one of the same type that most seem to be. It works well as a micrometer, or at least it did.. but the battery keeps running out and it does weird things frequently.

This picture shows the principle of how the error would be manifested (it may be small but it is there none the less 😊):

I get the principle – out of the 1000s I’ve personally calibrated and seen calibrated, I’ve never known one out more than the tolerance unless damaged. 😊

I get the principle – out of the 1000s I’ve personally calibrated and seen calibrated, I’ve never known one out more than the tolerance unless damaged

so your saying the tolerance is based on the anvil or is it possible if using flat anvils on an internal round surface your compounding your tolerance. – anvil interface X scale calibration

or are you calibrating them for use on an internal round surface ?

The tolerance is based over the length of the scale – a 150mm Caliper is accurate to ±0.02mm, a 300mm caliper is accurate to ±0.03mm etc.

When the internal jaws are calibrated they’re usually done with a 10mm and a 30mm std ring gauge, the 10mm is for the tips of the internal blades, the large for the whole blade. I’ve genuinely never seen one fail unless damaged – and that happened a lot.

Bear in mind, that error only comes in to play if you’re standardising using the external jaws, if you want to measure something using the internal jaws it’s best to standardise it with a calibrated ring round the same diameter you’re measuring. and if you’re worried about the potential errors in that diagram above you’re using the wrong tool to take a measurement.

I’ve had more than one frame off members on here on a CMM to measure the headset diameters. More recently I’ve had some handlebars in the UT bath looking for defects.

and if you’re worried about the potential errors in that diagram above you’re using the wrong tool to take a measurement

The diagram what I made is not quite right but to prove a point of principle it’s OK – the OP is looking for an absolute measurement of the size of the bore so is proposing to use the wrong tool, QED 😊

and if you’re worried about the potential errors in that diagram above you’re using the wrong tool to take a measurement.

I think that’s the take away point for what the op is proposing.

I’ve seen a few of those AvE reviews before. He seems to have a bit of a grudge against anything not made in the USA and that isn’t calibrated in inches. He seems to take pleasure in taking Festool and other tools apart, breaking them, losing bits, putting them back together and complaining they don’t work right.

From my limited experience all digital calipers only differ by the name printed on them. I assume they’re all made in the same factory in the Philippines.

Oh, and I always remove the battery after use and put it back into the holder in the case.

Cheap digital calipers are as accurate as the expensive ones provided that the battery is in good condition.

Once it begins to drain the cheaper ones can diverge quite wildly.