Thread: Interesting website that's worth having a look at

The guy cutting out with the torch is pretty impressive.

This micrometer is terrific.

Would he cut approx 30" diameter shaft to +/- a few thousandths ?

How big can micrometers get ?

Originally Posted by steamingbill

This micrometer is terrific.

Would he cut approx 30" diameter shaft to +/- a few thousandths ?

How big can micrometers get ?

Probably better tolerances than that. +- half a thou maybe.

I think there is a bigger Mic in a pic there, 2 blokes in white coats using it. You can't see much though, they are in the way.

Ew

Well I have a 700mm to 800mm mic.

Does anyone know how the crankshaft components are secured one to the other? I assume by shrink fit, but the guys doing the assembly don't seem too concerned that they are working right next to a big lump of 100 or 200°C steel. Could have even been a desirable job during an English winter.

Originally Posted by andrew_mx83

Im a bit confused by the gas axe. It looks like its meant to cut 2 parts simultaneously, but they seem to be making different bits on each end.
Can anybody shed some light as to how it works? Such as how are they cutting the arc?

Andrew,
The template on the profile table is steel and is followed by a magnetised roller.You can see the raised circular section for cutting out the centers .The templates are sized to be one half a roller/ follower diameter smaller than actual size of the part.

The part being cut is likely to be a crankshaft lobe. The electric motor that powers the roller is a variable speed jobbie and by definition would be geared down to some incredibly slow travel speed to enable the turtle like travel speed needed for such a thick cut.

The steel slab to be cut has to be very carefully leveled in both planes as any slight discrepancy in that thickness would result in the edges of cut being substantially out of square. The steel being cut lays on cones usually surfaced with material impervious to flame damage.
Cutting such a shape would be an art as the heat distortion often causes lateral movement which can bugger up the cut. It would mean cutting so far in one direction and then changing the direction of cut.for this reason the placement of the supporting cones would be performed with some care as well.

I spent a good deal of time (months) on such a table though not on thicknesses like that. My humble efforts were limited to up to 50mm thickness.


Grahame

Originally Posted by bob ward

Does anyone know how the crankshaft components are secured one to the other? I assume by shrink fit, but the guys doing the assembly don't seem too concerned that they are working right next to a big lump of 100 or 200°C steel. Could have even been a desirable job during an English winter.

If you are referring to the 2 photos showing the assembly of the crankshaft as below, this photo is named Shrink1.jpg and the next one is named Shrinking2.jpg


Shrink1.jpg

Thats the full extent of my knowledge.

Dean

Look at the size of the swarf. So no women allowed?

Grahame, thanks for the informative reply. Sounds like a fun job!

Originally Posted by Grahame Collins

Andrew,
The template on the profile table is steel and is followed by a magnetised roller.You can see the raised circular section for cutting out the centers .The templates are sized to be one half a roller/ follower diameter smaller than actual size of the part.

The part being cut is likely to be a crankshaft lobe. The electric motor that powers the roller is a variable speed jobbie and by definition would be geared down to some incredibly slow travel speed to enable the turtle like travel speed needed for such a thick cut.

The steel slab to be cut has to be very carefully leveled in both planes as any slight discrepancy in that thickness would result in the edges of cut being substantially out of square. The steel being cut lays on cones usually surfaced with material impervious to flame damage.
Cutting such a shape would be an art as the heat distortion often causes lateral movement which can bugger up the cut. It would mean cutting so far in one direction and then changing the direction of cut.for this reason the placement of the supporting cones would be performed with some care as well.

I spent a good deal of time (months) on such a table though not on thicknesses like that. My humble efforts were limited to up to 50mm thickness.


Grahame

Has anyone noticed how the bridge in the first photo steps up on the left bank, any idea's what the bridge is used for, can't be any thru traffic setup like that.
Thanks for posting Jim great site.

Originally Posted by matthew_g

Well I have a 700mm to 800mm mic.

Hey Matthew,

What things do you make 700 - 800mm wide that need that sort of accuracy ?

Whats your passing specification ? Plus minus 1 thousandth ? better ?

Bill the Curious

Originally Posted by steamingbill

Hey Matthew,

What things do you make 700 - 800mm wide that need that sort of accuracy ?

Bill the Curious

I'm guessing something to do with steam turbines? But then I not noted for my guessing prime examples being the Saturday lotto numbers or the grand final winner )

Anything that runs on a plain bearing under serious sorts of load would warrant such tolerances. The film of oil takes the load, helped by the supply of oil under pressure. The ability for that oil to leave the space between parts plays a role in maintaining oil pressure, so the clearance would have to be closely controled. If there are multiple bearings under the same pressurised oil feed and one bearing has significantly more clearance that the others, then the others will suffer a huge loss in pressure. So tight tolerances are essential.

Hi,

Great site. Those blokes in white coats must of been the supervisors, bet they where real mean b*stards.

Ben.