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Which metal for which job?

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Chris TickTock01/08/2019 11:20:42
163 forum posts
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Hi, my hobby (ney obsession) is horology or clocks to those who speak plain English.I have bought a Sherline lathe and mill and intend improving my very basic skills.

Before doing any work I wish to know what metal to use for a particular purpose.

Can anyone tell me in simple terms when to use and why I should use mild steel, when to use 01 or w1(stubbs) tool steel and when to use silver steel.

I have googles but answers are convoluted.

Regards

Chris

David Standing 101/08/2019 11:35:57
1266 forum posts
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Chris

That is an almost impossible question to answer - the glib reply is use mild steel when the work requires it, use tool steel where the work requires it, and use silver steel when the work requires it.

In effect, you are asking for the answer before the question is asked.

Mick B101/08/2019 11:56:41
1151 forum posts
63 photos

I always thought Stubbs was silver steel - at tleast the silver steel I used to buy was so marked, though I've more recently had silver steel that performed OK, but wasn't.

Since the mechanical clocks I've seen don't generally run at 'let-down' temperatures, and silver steel can more-or-less match tool steels in hardness at normal ones, and the severe abrasion prevalent in - say - fine-blanking press tool punches isn't a standard condition in clocks, I can't really see where tool steel would be necessary.

But hey, I don't really know anything specific about clocks, and there could easily be demands I'm unaware of. Perhaps if you have to harden a plate and preserve some very precise hole-centre placings, an NSOH tool steel like BO1 or similar might be indicated?

Vic01/08/2019 12:07:24
2206 forum posts
11 photos

Difficult question to answer as your requirements for any particular part may be slightly different from mine. I sometimes use stainless steel so parts don't go rusty quickly but its not really necessary in many cases, just a nicety. I’ve also used Guage plate or O1 steel not because the part needed that grade of steel but because it comes in a very large range of sizes and is nicely ground on all four sides. This can make producing small parts quite quickly with a minimum of machining. Another nice material is precision ground mild steel but my local supplier doesn’t stock it. Same thing with fasteners, I rarely buy anything other than stainless these days.

Bazyle01/08/2019 12:56:57
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Stubbs was an early quality supplier of silver steel. Silver steel is a high carbon steel so can be hardened unlike mild steel and comes in a fairly hard state so can be used for a number of jobs without further treatment. This is important because the heat treatment process can cause distortion but is sometimes necessary to get the right level of harness. You would use it for clock arbors and pinions since the specialist materials fro these jobs are no longer as readily available as they used to be. Also use it for making tools. It comes ground to size too. Don't get conned by piano wire which is processed in a different way but is hard and used for springs.

Guage plate is the same material as silver steel but in sheets and blocks. Use it for things that need to be hard like clicks and ratchet wheels.

Mild steel is easier to work so is used for brackets and things that need to be harder than brass but not special. You can process it to make the surface hard by case hardening which tends to be useful for making tools.

Although Vic mentions using stainless fasteners be aware that regular bog standard stainless screws and bolts are weaker than plain steel.

Vic01/08/2019 13:06:59
2206 forum posts
11 photos

That’s a good point Bazyle. I’ve never found it an issue for machine screws though. Wood screws on the other hand are a different matter, it’s all too easy to take the head off a stainless wood screw if you’re not careful! DAMHIKT. blush

SillyOldDuffer01/08/2019 16:07:44
4592 forum posts
980 photos
Posted by Christopher judd on 01/08/2019 11:20:42:

...

Before doing any work I wish to know what metal to use for a particular purpose.

Can anyone tell me in simple terms when to use and why I should use mild steel, when to use 01 or w1(stubbs) tool steel and when to use silver steel.

...

Chris

Compared with other steels Mild Steel is soft and easy to work with. It can be cut, drilled, filed, machined, chiselled, welded and brazed without much bother. Being cheap and fairly strong makes it particularly suitable for structural purposes, car bodies, girders, ships, and office-blocks. I tend to use it for parts requiring strength but not hardness, and where an edge isn't needed. (It is possible to 'Case Harden' mild-steel.)

O-1 and W-1 are American tool steels. Nothing exotic - similar steels are available worldwide under different identifiers. Tool steels contain more Carbon than mild steel making it possible to harden and soften the metal by appropriate heating and cooling. Typically used to make parts like axles that need to be hard and strong to resist friction damage, or tools that take a pounding. They can take and hold a sharp edge.  The workflow is usually to machine or forge parts to shape with the steel in soft condition and then heat treat to harden it when finished. Heat hardening consists of warming the metal cherry red and cooling it, usually in oil, 'tempering'. Judging the necessary temperatures and timing manually is a skiil.

There are a wide range of tool-steels tuned to particular purposes: different combinations of hardness, toughness, brittleness and strength. O1 is a cheap general purpose tool-steel good for making knives and axe heads etc. W1 is a water-tempering steel like Silver Steel. Silver Steel comes as attractive precision-ground rod, which makes it handy in soft form for many modelling purposes. But it's main purpose is making drills, taps and other tools that need to be very hard. The alloy is formulated to simplify doing that in an ordinary workshop. O-1, W-1 ans Silver Steel aren't ideal for making springs.

If a were a clockmaker, I'd use mild-steel for the structure, including nuts and bolts, brass for the working parts, and silver-steel for pinions and anything else likely to wear. A spring-steel is necessary for springs. A real clockmaker may know better!

This book on Workshop Materials is worth owning.

 

Edited By SillyOldDuffer on 01/08/2019 16:12:04

Russell Eberhardt01/08/2019 20:51:15
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Posted by Bazyle on 01/08/2019 12:56:57:

Silver steel is a high carbon steel <snip> You would use it for clock arbors and pinions since the specialist materials fro these jobs are no longer as readily available as they used to be.

Clockmakers suppliers still list pivot steel, a blued hard steel for making arbors. It is available from Meadows and Passemore from 0.33 mm to 3.22 mm diameter. It is also good for making lantern pinions. Silver steel is fine though.

Russell

old mart01/08/2019 21:27:07
442 forum posts
42 photos

Pivot steel is tempered to a greater hardness than regular silversteel, making it longer lasting when used with bearings. I always check the ends of ground steel stock to see if it has "Genuine Stubbs" on it. It then gets hidden away from idle metal manglers.

Nigel Graham 201/08/2019 21:27:41
357 forum posts

If you are making anything from published plans, the drawings should specify the appropriate material for each component.

I've never tried clock-making but I imagine the same would apply.

Whereabouts are though, Chris? Noting SillyOldDuffer's comment that O-1 and W-1 are American specifications, you are likely to find equivalents in the UK, but by EN (BS) designations.

Chris TickTock02/08/2019 13:30:52
163 forum posts
1 photos

Thank you yes everyone for truly great replies. Between these replies and my friends on the clock forum there is enough knowledge in my head now to state:

mild steel for brackets brackets

Silver steel (stubbs) or 01 or w1 tool steel most other things such as pivots, arbors etc

Do not use modern blue pivot steel as is inconsistent.

For fine, intricate work use silver steel hardened and tempered by bluing to get the right hardness first.

Anyone know why chromium is added?

Kind Regards

Chris

Chris TickTock02/08/2019 13:39:36
163 forum posts
1 photos

hi guys I have also just found out w1 steel is more like case hardened steel and that the hardness is more on the surface than all through the metal. Therefore the safer option is using 01 steel. Obviously dependent on application.

Chris

SillyOldDuffer02/08/2019 17:33:30
4592 forum posts
980 photos
Posted by Christopher judd on 02/08/2019 13:30:52:

...

mild steel for brackets brackets

Silver steel (stubbs) or 01 or w1 tool steel most other things such as pivots, arbors etc

Do not use modern blue pivot steel as is inconsistent.

For fine, intricate work use silver steel hardened and tempered by bluing to get the right hardness first.

Anyone know why chromium is added?

...

I have also just found out w1 steel is more like case hardened steel and that the hardness is more on the surface than all through the metal. Therefore the safer option is using 01 steel.

...

Mild steel for brackets etc, yes. Silver Steel, O-1 and W-1 are sold soft. They are easy to work and can be hardened before use. They are all better than mild steel for working parts likely to wear over time.

Blue pivot steel is sold hard and I guess is mostly shaped by grinding. There are times when pre-hardened steel is exactly right and times when it's a bad choice. The most likely explanation for inconsistency in Pivot Steel is buying cheapo from unreliable sources - what you get may not be pivot steel at all. Pay full price from a reputable supplier.

A disadvantage of O-2 is that quenching incorrectly can crack the metal or leave it dangerously weak and brittle. W-1 is easier to harden than O-2 and staying soft inside leaves it tougher than O-2 which is useful for many applications. As hardening is skilled work it pays to practice on odd bits of metal before trying it on a carefully made part that took hours to make. You have to judge temperature and soak time. With O-2 choice of quenching oil makes a difference too. I've not looked it up, but memory suggests Canola or similar, not old engine oil. Metal is moved from heat to quench as fast as possible, and agitate in the liquid briskly. Too low a temperature and the steel won't harden. Over high temperatures can damage the steel internally and make cracking and warping more likely during the quench, or burn the steel. Hardening is a bit 'three strikes and you're out' : every time the metal is heated it loses some of it's structure.

A good test of hardness is to run a file over the metal. In soft condition the file should bite; after hardening the file should skate over the surface.

Chromium is one of several metals alloyed with steel to improve it. Small quantities make steel stronger, higher quantities add corrosion resistance - 'Stainless Steel'. There are thousands of different steels out there, some are good to work with, others yuk. Nigel mentioned following the plans on choice of materials - always good advice.

Based on my learning disasters, I think O-1 vs W-1 vs Silver Steel won't make much difference until more experience is gained. Cocking up the heat treatment is more likely to cause bother in the early stages of a clock making career I think than choice of steel.

John Harrison made a lot of clocks in wood, now there's a challenge!

Dave

 

Edited By SillyOldDuffer on 02/08/2019 17:36:18

Chris TickTock02/08/2019 18:03:20
163 forum posts
1 photos

Great reply I would add I may be thinking of using a toaster oven to temper my metal which is a scaled down version of how the big boys do it. Anyone who can make a clock out of wood deserves respect. When you buy metal let's say silver steel and I intended for arguments sake to use it to make a very small intricate piece would the hardening and tempering temperatures be given from the supplier?

Regards

Chris

roy entwistle02/08/2019 19:30:34
1021 forum posts

I have bought gauge plate in the past that was wrapped in anti rust paper that had hardening and tempering instructions printed thereon.

Roy

Russell Eberhardt06/08/2019 10:32:01
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2476 forum posts
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Pivot steel can be turned using a sharp HSS tool. More traditional clockmakers would turn it freehand using a carbon steel graver. Having said that silver steel is fine for a first clock and needn't be hardened. Finishing the pivot with a burnisher should give sufficient hardness. Hardening it after turning risks distortion.

Russell

Martin Kyte06/08/2019 13:35:45
1472 forum posts
24 photos

Not comprehensive but have a go at this for starters.

Leaded engraving Brass for plates and wheels. Brass rod or tube for collets, pillars, barrels Blued pivot steel or silver steel for arbors and pins for lantern pinions, silver steel for solid pinions, Guage plate for clicks, piano wire or silver steel for wire springs, you may use mild steel for pendulum rods, bell cranks and sundry items. Large turret clocks may employ a greater amount of mild steel for framework but the use of brass or bronze bearing surfaces in the form of bushes is essential.

If you are starting out as a clockmaker all the available clock designs specify materials.

regards Martin

Bazyle06/08/2019 16:29:37
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4681 forum posts
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You asked about hardening and tempering instructions. It would be a good idea to get one of the Wilding books for a simpler clock even if you don't make it as he gives instructions on lots of the important techniques. Also in many of the articles in ME over the years.

Tim Stevens06/08/2019 17:11:07
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1056 forum posts

Chromium is added to a steel mix (along with a range of other metals) to change the characteristics of the resulting steel. Why and how are questions which take too long to answer here. If you are keen to know more, metallurgy is the name of the science (for when you are visiting a proper book shop*) but you might like to start on Wiki.

* a proper book shop is one that sells books I want to buy. Very rare, nowadays.

Cheers, Tim

Neil Wyatt07/08/2019 18:21:51
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Posted by Nigel Graham 2 on 01/08/2019 21:27:41:

Noting SillyOldDuffer's comment that O-1 and W-1 are American specifications, you are likely to find equivalents in the UK, but by EN (BS) designations.

In broad terms 'O1' is oil-hardening, like gauge plate.

'W1' is water hardening (e.g. drill rod), like silver steel but typically without some element (molybdenum?) that makes silver steel less liable to distortion.

Neil

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