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Vibrating wheel hub puller.
<video controls autoplay loop> <source src="https://diqn32j8nouaz.cloudfront.net/vibrating_hub_puller_heated.mp4" type="video/mp4"> Your browser does not support the video tag. </video>
Previously:
https://www.homemadetools.net/forum/...835#post190688
https://www.homemadetools.net/forum/...900#post171488
https://www.homemadetools.net/forum/...475#post185603
https://www.homemadetools.net/forum/...463#post177692
https://www.homemadetools.net/forum/...742#post163464
Seeing the heating that’s going on reminded me of something thats always puzzled me.
Leaving aside potential damage to the ‘wanted’ bits, is it more logical to heat the outer component or the inner component of a frozen coaxial apparatus?
Heating the outer component would make it expand (in all directions) making its internal diameter smaller thereby binding even tighter.
Heating the inner component (again expanding in all directions) would increase its outer diameter thereby binding even tighter.
Does anyone have a logical explanation of which is better?
I think it's just a perspective issue with the camera. You definitely want to heat the hub and not the spindle.Quote:
Originally Posted by WorkerB
Heating the outer component makes it expand as you say but its inner diameter expands away from the centre not towards it. If the hole expanded inward and the outside expanded outward as you propose then there would have to be a ring between those two extremes that did not expand. This is not the reality.Quote:
Originally Posted by WorkerB
Imagine the circumference of the hole, if that circumference expanded then its diameter also has to expand not close up.
Imagine the hub as being a set of concentric rings, each ring will expand such that inner and outer diameters will expand outward, therefore the whole object will expand outward.
So you need to heat the outer part.
I recall asking my school teacher a similar question close to 70 years ago. He was unable to provide an answer.
Am I going blind? I do not see the source of the vibration, that would be the only interesting thing in that video.Quote:
Originally Posted by Altair
Thank you so much Tony.
It makes sense now. Like a doughnut (or is that donut in the US) increasing in size. The hole gets enlarged too. Brilliant!!
Make mine a doughnut.Quote:
Originally Posted by WorkerB
I used to repair Salsbury axles on Scimitars and the method which worked every time was to pour two kettles of boiling water over the hub which would then fall of the taper with a couple of blows of a copper mallet. Trick is to expand the hub before the heat gets to the shaft. Hydraulic puller methods can be a bit scary when they let go.
based on the noise i figured the vibration is actually an air powered impact socket driver running on the puller screw.Quote:
Originally Posted by tonyfoale
Was taught that in grade 7 science class, 1950sQuote:
Originally Posted by tonyfoale
As a mathematician* your description really appeals to me. It is the mechanical example of the Intermediate Value Theorem...Quote:
Originally Posted by tonyfoale
https://en.wikipedia.org/wiki/Interm..._value_theorem
from which this quote...
"In mathematical analysis, the intermediate value theorem states that if f is a continuous function whose domain contains the interval [a, b], then it takes on any given value between f (a) and f (b) at some point within the interval."
--
* OK, I'm not really a mathematician. My degrees all say 'physics' on them but, when you study physics, you automatically get deeply involved with mathematics. I enjoy math and have continued learning about it long after leaving school.
As noted in a previous post, the vibrations were from the Pneumatic Impact Wrench being used to turn the tension screw on the puller. In this application, the hub assembly is able to twist in response to the wrench impacts. Any additional torque the impact might provide is lost by moving the entire spindle/hub/puller assembly.Quote:
Originally Posted by Altair
The effect is similar to trying to drive a nail into a board that moves with every stoke. Most of the energy that should be driving the nail is used up moving the board instead. Just a fraction is used actually driving the nail.
A better way to remove a stuck hub, is to tension the puller with with just a normal wrench. In this situation you apply more torque than with the impact wrench. Then use a pneumatic HAMMER on the center screw of the puller to induce linear vibrations that will actually act in a manner to pull the hub from the shaft.
If you do much of this kind of work, you need a pneumatic hammer.
Thankfully I never had to do anything on my Scimi's axles (2x SE5, 1 x SE5a, 1 x SE6) but my 20lb slide-hammer was favoured for other vehicles.Quote:
Originally Posted by olderdan
I owned 1x SE5A, 1xSE5 and a straight 6 Coupe. All had growly diffs so needed rebuilds, quiet as a church mouse afterwards. Also all fitted with Granada 5 speed boxes, great fun to drive but the old Essex is too thirsty these days.Quote:
Originally Posted by NeiljohnUK
Thirst wasn't such an issue then, had a set of triple DCNF's on a 3 litre Essex, https://www.webcon.co.uk/products/10...-carburettors/ those are thirsty!Quote:
Originally Posted by olderdan
I gather there's even a manifold for the Colone V6 for DCNF's now https://www.webcon.co.uk/products/16...-carburettors/ .
We also bolted a set of six IDF's onto a Jag v12 to improve the limited performance the fuel injection system caused, if thirst is what you want those are pretty good! https://www.webcon.co.uk/products/10...6-x-weber-idf/