What's on your bench today?

[Khriss]

Torn a ring once using string, ain't best idea. K

[Gary Prentice]

2 hours ago, Khriss said:

Torn a ring once using string, ain't best idea. K

That sounds painful, and a bit deviant!

[peatff]

3 hours ago, Khriss said:

Torn a ring once using string, ain't best idea. K

 

Well you will climb in that thong

[Khriss]

2 hours ago, peatff said:

 

Well you will climb in that thong

It's a comfort issue n non of yr business k

[Khriss]

Obviously yr supposed to tie a knot in it- but it still crept into my port n smeared badly...... k

[spudulike]

On ‎18‎/‎11‎/‎2018 at 10:24, bmp01 said:

Pistons are forged (not cast). 

Something nagged at me on this one. Couple of things - when I look at pistons, I see casting flash, slight unevenness in inner surfaces or casting witness marks and then machining to the critical surfaces and parts. The piston body shows obvious signs of casting - the machining will be common to all pistons.

I then remember my days on bikes and being able to fit Wiseco "Forged" pistons and then thought, if all pistons are forged, why make such a thing out of being forged.

So...basically, cast is molten metal in to a moulding cast and forged is battering solid metal using heat to soften and "forge" shape - like a blacksmith making horseshoes!

I then Googled it and most pistons are cast but the top end ones for racing or high revving engines are forged.....ah, reconciliation in my head once more 

Sorry but your statement is wrong, perhaps you have come from only using race pistons - come across them in bike and car track racing and drag racing then assumed.......

No offence meant and don't intend any ridicule but this one just "niggled" at what I understood to be fact!

[bmp01]

2 hours ago, spudulike said:

Something nagged at me on this one. Couple of things - when I look at pistons, I see casting flash, slight unevenness in inner surfaces or casting witness marks and then machining to the critical surfaces and parts. The piston body shows obvious signs of casting - the machining will be common to all pistons.

I then remember my days on bikes and being able to fit Wiseco "Forged" pistons and then thought, if all pistons are forged, why make such a thing out of being forged.

So...basically, cast is molten metal in to a moulding cast and forged is battering solid metal using heat to soften and "forge" shape - like a blacksmith making horseshoes!

I then Googled it and most pistons are cast but the top end ones for racing or high revving engines are forged.....ah, reconciliation in my head once more 

Sorry but your statement is wrong, perhaps you have come from only using race pistons - come across them in bike and car track racing and drag racing then assumed.......

No offence meant and don't intend any ridicule but this one just "niggled" at what I understood to be fact!

Spud, 

No offence taken. My statement was bollox (I now realise). It needed correcting and any confusion clearing up. Not good to have doubt thrown into ones understanding of things, sorry about that. And thanks for taking the time to point out my error. 

 

Yes I'm from a racing back ground but that's not an excuse, I believed (incorrectly) all modern pistons were forged,  i was wrong, simple as. I'll go and adjust the grey matter now.

 

Forged pistons - yes the're hit with a punch but the process is a bit slower than you might imagine, there's the initial contact followed by the second stage where the punch is pressed into the material.  Even though the material is heated sufficiently to make it ductile the forge is a big bit of kit, close to 100 tonnes the one I experienced, maximum of 5 inch dameter forgings. The advantage of forging over cast (generally) is to get the material grain structure aligned to the shape of the piston, for strength and durability. Getting clear part numbers on a forged piston is relatively easy. Forgings were better than machined from solid but only marginally so in the game i was involved with. 

With a forging there's no way to get windows in the piston side panels nor the undercut below the g'pin boss, unless they're machined afterwards. So there you go chainsaw pistons often have both those features... must be cast. Fancy split tooling as well, to achieve that, split lines are the cause of the flash lines you see. 

 

 

[spudulike]

Thanks, all cleared up now. I always had them down as cast and he statement threw me. Glad all is cleared up now.

[westphalian]

what's on my bench? my friggin chainsaw cos i forgot to replace the e ring when changing the sprocket and now the bearing is fcuked?

[Ratman]

what's on my bench? my friggin chainsaw cos i forgot to replace the e ring when changing the sprocket and now the bearing is fcuked?

[emoji849]??‍♂️[emoji110][emoji97][emoji97]?