Todays Project - What did you do today?

[PixMan]

Tom,

No need for that, Neil can buy stainless steel cotter pins for them.

I finished up the second of them tonight. Here it is next to the one it is replacing, with the other two behind them.

[awemawson]

'Split Pins' surely ? A cotter pin is cylindrical with a tapered flat and often a thread to pull it tight into it's hole. Often used on bicycles as the pedal crank retainer.

Or is this a US / UK language thing ?



  1-32-split-pins-9253-p.jpg (Size: 5.06 KB / Downloads: 150)


  cotter-pin.jpg (Size: 28.16 KB / Downloads: 151)

[Mayhem]

I concur - we call them split pins here.

[EdK]

We've always called those cotter pins. It must be a regional thing. Straight from Wikipedia.

"A split pin, also known in the U.S. usage as a cotter pin or cotter key,[1] is a metal fastener with two tines that are bent during installation, similar to a staple or rivet. Typically made of thick wire with a half-circular cross section, split pins come in multiple sizes and types.

The British definition of "cotter pin" is equivalent to U.S. term "cotter", which can be a cause for confusion when companies of both countries work together. There are signs that manufacturers and stockists are increasingly listing both names together to avoid confusion; this led to the term split cotter sometimes being used for a split pin."

Ed

[Mayhem]

so what do you call cotter pins Ed?

[TomG]

(04-15-2014, 02:15 AM)awemawson Wrote: 'Split Pins' surely ? A cotter pin is cylindrical with a tapered flat and often a thread to pull it tight into it's hole. Often used on bicycles as the pedal crank retainer.

Or is this a US / UK language thing ?

Those pins are not a common piece of hardware over here. As far as I know, bicycle cranks are the only place they are used. "Cotter pin" is the common name for what you guys call split pins.

I'll bet that inconsistency has caused heartburn for many joint US/UK manufacturing project engineers.

Tom

[PixMan]

I got about two hours in the shop after work today to try and knock out another little job for Neil. It's a pair of pistons for the front brake calipers on his Yamaha RD350 (or was that RZ350?) motorcycle rebuild project.

The original ones are made of some kind of fairly hard cast steel and are pitted badly from moisture getting into the system over the past 30 years. We discussed various stainless steels and almost went with a piece of 431ss he'd found. Fortunately it was too small and I'd thought of making them from the best, somewhat hard and extremely corrosion resistant material...17-4PH (precipitation hardened) stainless steel. I found a 4-1/4" long piece of 2" diameter, H900 condition, thinking that would be enough for one and have extra for when I screw up the first one. Then Neil reminded me he needs TWO of them! No room for error now.

The day before yesterday Neil came over and roughed out the bores with a carbide insert plunge mill/drill I have, a Valenite V520 (discontinued product.) He finished the bores to depth, and rough turned one of the O.D.'s. Today I finished the O.D. on both to EXACTLY 37.97mm (1.4949"), which is EXACTLY what the old sample is. I absolutely LOVE working with 17-4PH! It may be tough on the wrong tools, but I have all the right carbide tools for it and it's a joy. Best of all, it polishes easily to a very fine finish, a mirror if you want one.

I stopped at and 800 grit silicon carbide paper. Turned to 1.4954", polish the tool marks out with some 180 grit, hit it with a piece of ScotchBrite (about 320 grit), a few seconds with 600 grit silicon carbide paper, then final with the 800. If I wanted round mirrors I still have 1000, 1500, 2000 and 2500 grit, but the finish on the pistons need just a little surface texture to keep the rubber quad ring seals working.

One is done completely, the other just needs the end faced, radiused and recessed. Here's the one finished one:

[Expat]

(04-16-2014, 07:44 PM)PixMan Wrote: I got about two hours in the shop after work today to try and knock out another little job for Neil. It's a pair of pistons for the front brake calipers on his Yamaha RD350 (or was that RZ350?) motorcycle rebuild project.

The original ones are made of some kind of fairly hard cast steel and are pitted badly from moisture getting into the system over the past 30 years. We discussed various stainless steels and almost went with a piece of 431ss he'd found. Fortunately it was too small and I'd thought of making them from the best, somewhat hard and extremely corrosion resistant material...17-4PH (precipitation hardened) stainless steel. I found a 4-1/4" long piece of 2" diameter, H900 condition, thinking that would be enough for one and have extra for when I screw up the first one. Then Neil reminded me he needs TWO of them! No room for error now.

The day before yesterday Neil came over and roughed out the bores with a carbide insert plunge mill/drill I have, a Valenite V520 (discontinued product.) He finished the bores to depth, and rough turned one of the O.D.'s. Today I finished the O.D. on both to EXACTLY 37.97mm (1.4949"), which is EXACTLY what the old sample is. I absolutely LOVE working with 17-4PH! It may be tough on the wrong tools, but I have all the right carbide tools for it and it's a joy. Best of all, it polishes easily to a very fine finish, a mirror if you want one.

I stopped at and 800 grit silicon carbide paper. Turned to 1.4954", polish the tool marks out with some 180 grit, hit it with a piece of ScotchBrite (about 320 grit), a few seconds with 600 grit silicon carbide paper, then final with the 800. If I wanted round mirrors I still have 1000, 1500, 2000 and 2500 grit, but the finish on the pistons need just a little surface texture to keep the rubber quad ring seals working.

One is done completely, the other just needs the end faced, radiused and recessed. Here's the one finished one:

WOW! Those look great! It's a pity they will live inside a brake caliper.
This bike is coming along and will look incredible when complete.
I will post some pics when it's a little further along, in the meant time, yet another huge thanks to Ken! His skills on the lathe and mill are a scarce commodity these days, a true craftsman.

[PixMan]

(04-16-2014, 08:21 PM)Expat Wrote: WOW! Those look great! It's a pity they will live inside a brake caliper.
This bike is coming along and will look incredible when complete.
I will post some pics when it's a little further along, in the meant time, yet another huge thanks to Ken! His skills on the lathe and mill are a scarce commodity these days, a true craftsman.

Thanks Neil!

Yeah, I really wish there was a "see thru" caliper so people could see them.

BTW, to get the final polish on that one I'd taken a piece of 1-1/4" aluminum (or aluminium, as you prefer), threw it in the 3-jaw chuck and used a coarse tooth file to quickly get a slight taper to the diameter. I then twisted the bore of the piston onto it and gave it a once-over with the 800 grit paper for a consistent finish across the length. I'll do that with the other as well tomorrow.

[Mayhem]

Excellent work Ken - you'll have to make Neil a third one to have as a paper weight, so he can admire the work. I'm planning on using mirrors on my mill, so I can see the elevating screw and nut in any position