Balance Staff, just can’t get to 0.2

[Daniel123]

Hi Guys, For some reason my graver just seems to stop working at about 0.4 when turning the pivot. I then inevitably push to hard and break the pivot. I must have sharpened my graver a dozen times. Am I missing something?

p.s it’s a practice balance staff only my first.

[nickelsilver]

What kind of graver are you using? Should be able to cut to basically "zero" even with steel, if it's really sharp. With steel you do have to sharpen frequently when cutting blued steel. With carbide, it really helps to have the finest finish possible. When I was young diamond grinding wheels were expensive, so is was normal to have a fairly rough one and that was that. For a finer finish on gravers, we used a lap with diamond paste, like 3 micron. The lap can be almost anything, I have used brass, steel, plexi, it all works. Now you can get quite fine diamond wheels for a reasonable price, a D14 is already quite good, or if you want close to mirror a D7 is nice.

 

The angle at which you approach the work is very critical, more and more so as the diameter decreases. You should be seeing nice curly clean chips coming off the work, certainly at larger diameters. As the diameter goes down you need to still be getting proper chips, but you won't have the 10cm long curls coming off anymore, they will be really small. But you need to be making chips, not dust. If you have to increase pressure to cut, either the steel is too hard, or there's a sharpness issue or angle of attack issue. I'm not a big fan of premade blue steel rod, but I have yet to encounter any that couldn't be cut with a steel graver.

[Daniel123]

That’s helpful thanks, the gravers are Valorbe from Cousins. It may well be the angle or how I am sharpening. I’ll will start again on new balance, it may be I need to practice sharpening first.

[nickelsilver]

It was typical in schools to spend weeks (or even months) hand turning; I don't know how much experience you have, but it does take some time to get the feel. In a school setting you would start off with brass, then move to steel in its annealed state, making tools and such, and finally get to turning blued steel making larger items, then pivot gages, and finally balance staffs. Even with that build up students frequently struggled with the staffs- so don't feel bad if it isn't going great right away!

 

Also, many people run the lathe way too fast, especially for turning heat treated steel. 1500rpm is plenty.

[Daniel123]

Early years I was experienced on industrial lathes but this is a new world. I suppose I’m quite relaxed so I just try try and try again. I will try cutting at lower speeds, I must admit I do need to do some maths and work out the speed ratios. 

[JohnR725]

17 minutes ago, nickelsilver said:

It was typical in schools to spend weeks (or even months) hand turning; I don't know how much experience you have, but it does take some time to get the feel. In a school setting you would start off with brass, then move to steel in its annealed state, making tools and such, and finally get to turning blued steel making larger items, then pivot gages, and finally balance staffs. Even with that build up students frequently struggled with the staffs- so don't feel bad if it isn't going great right away!

Yes the classic problem of watch repair it takes time to learn. Going to school is all about practicing continuous practicing and when you get out of school were still practicing we are forever practicing.

2 hours ago, Daniel123 said:

practice balance staff

The other thing that comes to play is what exactly is the balance staff made out of? Then have you hardened it at all before cutting?

[Daniel123]

Hi, it’s blued steel again from cousins 

[praezis]

10 minutes ago, Daniel123 said:

Hi, it’s blued steel again from cousins 

Maybe of indian origin and unknown quality.

You can use silversteel, harden it and temper (heat) it to light blue.

[JohnR725]

1 minute ago, praezis said:

aybe of indian origin and unknown quality.

You can use silversteel, harden it and temper (heat) it to light blue.

I remember purchasing an assortment of blued steel wire once and I had to wonder if maybe it was actually died blue as opposed to actually blued steel and I'm sure it was from India even though is a long time ago.

My favorite examples of things like this I was at a lecture were somebody made a cutter of fly cutter for cutting clock gears and skipped one of the steps for hardening. Normally when you harden something it should be very very hard before you draw the tempera you normally take a file to verify that it is actually hard that step was skipped. Off he went to cut his wheel and is cutter actually folded over on itself because I think it might've been stainless steel.

Or somebody else was in someone else's shop needed some flat steel ran down to the miscellaneous scrap found a piece of I think it was packing steel but it was blue in color. In other words the steel tape they put around big packages like pallets and things and whatever it was it totally sucked for the part he was making as usual typically finding out way too late in the process

say yes it really works better if you know exactly what you're dealing with even if it did come in a package with says blued steel. Just because it's blue doesn't actually mean well much of anything to be honest.

[Daniel123]

Where do you guys buy your steel from?

[nickelsilver]

1 hour ago, Daniel123 said:

Where do you guys buy your steel from?

I use Sandvik 20AP, which I get from Klein Metals. For "blue" steel, I have some old stock and got some from Selva more recently which has proven decent. I see Cousins has blue steel bars listed as UK Made, and then other stuff with no country of origin at a much lower price. I would steer clear of the cheap stuff.

 

Over there I see you can get "silver steel", also known as Stubbs steel, quite reasonably; Coventry Grinders has it in small quantities. This is a nice material and easy to heat treat with a propane torch and a glass of thin oil. While technically it's a water quenching steel, at small diameters like you'd encounter for watch work oil works fine and decreases the chance of deformation during quench.

 

I use blue steel for random things like pins and such, but for making a staff or other more demanding items, I use proper steel with a known makeup and heat treat it myself. If making a staff or stem, I make it prior to heat treatment (though I leave the pivots way oversize and finish turn post heat treat). Especially for stems, you don't want to thread it heat treated, unless you like tracking down and paying for expensive and hard to find dies!.

[nevenbekriev]

Hi Daniel,

It is important to inform what way of turning the staff You have choosen. Is it on T-rest with hand held gravers or with cros-slide support? This are quite different approaches and we will give beter advices if we know what You are doing.

As I understand, You have HSS gravers. Well, HSS this days is not what it was say 50 years before, as they don't put tunsten in it any more. So, in practice, modern HSS tools are good for nothing. Old ones will probably do. New HSS tools with cobalt perform beter and are close to performance of old HSS tools.

One possible reason for pivot turning problems is the steel is soft. Soft steel will tend to bend and stick to the tip of the graver. The other possible reason is the steel is to hard for the graver. If You let the material to get burnished instead of cut clear, the surface gets even more hard and thus HSS graver tip will get dull and will burnish further instead of cutting. So, turning needs correct position of the graver and attack angles, this is especially magnified when cutter is HSS. So, my advice is to use carbide cutters.

The hardening of the steel is another, different craft, that needs a lot of learning. Preparing of the steel for balance staffs (and all other parts) needs to be made avoiding risks of incorrect heat treatment. The main risk is to overheat the steel - this makes it brittle and useless. Of course, one must know what kind of steel is to be hardened and what are it's critical temperatures. But typically for tool steel with 1% carbon content, heating for the hardening must be about 750 degr. celsius and no more than 790. Heating above 800 degr. ruins the steel making it with big crystals in the structure and brittle.  So If You will heat treat the steel by Youself, make experiments with examples that You will break after hardening and bluing to ensure that the structure is uniform grey color with very small crystals.

The easier way for beginner is to use rollers from roller bearings. They are (usually) made from good steel and need only blue tempering.

 

[Daniel123]

Hi, I’m using a T rest with gravers to cut the balance. I have noticed that the metal is burnishing so possibly it how I’m holding the graver.

[SwissSeiko]

How are you holding the graver? I make sure I hold it similar to a pencil, to say I'm not really holding the handle. Hardened steel is a bit harder to turn, but I havent found it to be that much more difficult. I get my steel in the US from McMaster Carr, but that might not be an option for you. What is your graver shape? Diamond? that is easiest to use I think. I shape the tips on a diamond wheel, then polish them with a ruby stone. I have been able to turn this way down to 0.05mm. Again, the steel must be hard, as stated above, or it will be too sticky, like aluminum.

[Daniel123]

Hi, I’m using a diamond graver I’ll try holding it like a pencil, but I reckon the steel is to hard

[Neverenoughwatches]

5 hours ago, nevenbekriev said:

Hi Daniel,

It is important to inform what way of turning the staff You have choosen. Is it on T-rest with hand held gravers or with cros-slide support? This are quite different approaches and we will give beter advices if we know what You are doing.

As I understand, You have HSS gravers. Well, HSS this days is not what it was say 50 years before, as they don't put tunsten in it any more. So, in practice, modern HSS tools are good for nothing. Old ones will probably do. New HSS tools with cobalt perform beter and are close to performance of old HSS tools.

One possible reason for pivot turning problems is the steel is soft. Soft steel will tend to bend and stick to the tip of the graver. The other possible reason is the steel is to hard for the graver. If You let the material to get burnished instead of cut clear, the surface gets even more hard and thus HSS graver tip will get dull and will burnish further instead of cutting. So, turning needs correct position of the graver and attack angles, this is especially magnified when cutter is HSS. So, my advice is to use carbide cutters.

The hardening of the steel is another, different craft, that needs a lot of learning. Preparing of the steel for balance staffs (and all other parts) needs to be made avoiding risks of incorrect heat treatment. The main risk is to overheat the steel - this makes it brittle and useless. Of course, one must know what kind of steel is to be hardened and what are it's critical temperatures. But typically for tool steel with 1% carbon content, heating for the hardening must be about 750 degr. celsius and no more than 790. Heating above 800 degr. ruins the steel making it with big crystals in the structure and brittle.  So If You will heat treat the steel by Youself, make experiments with examples that You will break after hardening and bluing to ensure that the structure is uniform grey color with very small crystals.

The easier way for beginner is to use rollers from roller bearings. They are (usually) made from good steel and need only blue tempering.

 

Hiya Nev do you use magnetism to determine steel's temperature? 

[SwissSeiko]

9 minutes ago, Neverenoughwatches said:

Hiya Nev do you use magnetism to determine steel's temperature? 

Im not nev, but color is what you use.

[Neverenoughwatches]

9 minutes ago, Daniel123 said:

Hi, I’m using a diamond graver I’ll try holding it like a pencil, but I reckon the steel is to hard

I was having a similar problem last week, i switched from hss to using pieces of carbide for cutting and managed to get small swirls coming off some 0.3mm cousins blue steel cutting down to well under 0.1mm before the end broke off. Feels like x40 magnification isn't enough when trying to cut staff pivot dimensions. 

2 minutes ago, SwissSeiko said:

Im not nev, but color is what you use.

At least one of us is mixed up here

4 minutes ago, SwissSeiko said:

Im not nev, but color is what you use.

Magnetism would be a  good indication of where the temperature is at.

[SwissSeiko]

6 minutes ago, Neverenoughwatches said:

Magnetism would be a  good indication of where the temperature is at.

I'm sure this works on larger pieces, but with a piece the size of a balance staff, even air cooling can affect hardness, I don't know how you could measure it before its cooled down. But I don't know how measuring it works. When I harden my steel for turning, its held over a jar of oil and the flame is maybe an inch above it, so it can be dropped immediately. These small pieces just don't hold heat that well, and its hard to judge hardness.

 

27 minutes ago, Daniel123 said:

Hi, I’m using a diamond graver I’ll try holding it like a pencil, but I reckon the steel is to hard

Do you know what the graver steel is? HSS is good for most stuff, but I prefer O1 steel as I think it holds an edge better.

[nevenbekriev]

8 minutes ago, Neverenoughwatches said:

I was having a similar problem last week, i switched from hss to using pieces of carbide for cutting and managed to get small swirls coming off some 0.3mm cousins blue steel cutting down to well under 0.1mm before the end broke off. Feels like x40 magnification isn't enough when trying to cut staff pivot dimensions.

OK, some practice and things will get beter. Trust me, I don't have microscope , I use only Optivisor #7 glasses. Before having them, I only used watchmakers loupe 5X on one eye. In the beginning, when I was learning (at age of 14), I had only this loupe and actually I coud not use it for work but only for observation, as was not able to grasp things with the tweezers - grasped in front of the thing or behind it. So I worked with naked eyes only.

The temperature of the heated steel is indicated by the color of the light that it shines with

[RichardHarris123]

Many industrial processes use colour to determine temperature. 

[Neverenoughwatches]

34 minutes ago, SwissSeiko said:

I'm sure this works on larger pieces, but with a piece the size of a balance staff, even air cooling can affect hardness, I don't know how you could measure it before its cooled down. But I don't know how measuring it works. When I harden my steel for turning, its held over a jar of oil and the flame is maybe an inch above it, so it can be dropped immediately. These small pieces just don't hold heat that well, and its hard to judge hardness.

 

Do you know what the graver steel is? HSS is good for most stuff, but I prefer O1 steel as I think it holds an edge better.

This sounds way too easy to work, but if the staff was magnetised and held to steel and both were heated the staff would lose its magnetism at around 800 ° C  and fall off in to the oil.  Yey or nay ?

Edited Tuesday at 08:53 PM by Neverenoughwatches

[nevenbekriev]

21 minutes ago, Neverenoughwatches said:

This sounds way too easy to work, but if the staff was magnetised and held to steel and both were heated the staff would lose its magnetism at around 800 ° C  and fall off in to the oil.  Yey or nay ?

Interesting idea. Must be tested. I am not sure if the stream of the torch will not 'blow away' the piece.

[SwissSeiko]

26 minutes ago, Neverenoughwatches said:

This sounds way too easy to work, but if the staff was magnetised and held to steel and both were heated the staff would lose its magnetism at around 800 ° C  and fall off in to the oil.  Yey or nay ?

Most silver tool steel hardens at around 1000 C, so I'm not sure it would fully get hardened. I know I've had some instances where I was hardening silver steel and I didn't get it to glass hardened and I had to start the piece over. That's not a big deal with a pivot as its small. But if making a cutting tool, you have to re anneal it to its original state and that can be a pain, as they want it held at the annealing temp for a long time. Since I make my own cutting tools, i really focus on the hardening aspect because it will really cause me issues if I don't take it far enough, or if I go too far.

[Daniel123]

So did some work on a new staff last night and the gravers went blunt very quickly then ended up burnishing the metal. So I suspect it’s my gravers. I’ll have a look on eBay see if I can get some older gravers.