Dial Hand Length Ratio = rule of thumb

[Waggy]

I have a few cheaper watches where I have missing hands and I'm looking at generic replacements from my existing spares. But, I always end up second guessing myself if the size is correct. Are there any rules of thumb as to the size of hands relative to the dial size and relative to each other - looking for something along the lines of (and I'm making up the below):

• Visible dial radius = r
• Hour hand length = 0.5 x r
• Minute hand length = 0.75 x r
• Second hand length = 0.9 x r

Is there a real accepted hand/dial length ratio (not the one above I just made up above on the spot) or any rules of thumb anyone uses from experience? I know there will be exceptions where a manufacturer for one reason or the other over or under sizes the hands, but I'm looking for guidance for your average run of the mill watch.

 

Edited May 8, 2023 by Waggy
Clarification

[oldhippy]

Not that I know of. If the dial has a minute ring have the hand the length so it is on it, you need to make sure the hand doesn't touch or rub the inside of the glass. You could google old watches that should give you ideas of the length of minute hands and there style.  

[Waggy]

OK, so I did some research myself and decided to share it here:

If we take r as the outside of the chapter markings (the line indicated by the arrow above, not necessarily the radius of the dial or visible area) indicated by the arrow in the above. Hand lengths are relative to the centre of the hole in the hand, and do not include any 'tail' that extends beyond the hole. Here is what I found looking at Seiko's regular round dials:

• Outer edge of chapter markings radius = r
• Hour hand length = 0.65 x r
• Minute hand length = 0.95 x r
• Second hand length = 0.975 x r

I looked at about 15 Seiko watches of different styles taking the median values, however, the numbers were reasonably consistent. If I find more time I may look at other brands, or maybe some of the readers here can add their numbers and see if there are any trends or consistency across brands? 

Edited May 15, 2023 by Waggy

[Knebo]

Hey @Waggy

Why don't you share some pictures of those dials? Then maybe we can give better and more concrete advice.

I agree with @oldhippythat there's isn't a specific ratio. You should first look at the features of the dial, specifically hour markers and minute markers. Most of the time, the hands are adjusted to those. 

See the attached picture for an example. You can clearly see how the hour hand nicely "touches" the tip of the hour marker; and how the minute hand reaches the minute track.

It may not always be so obvious, though.

On 5/8/2023 at 8:36 AM, oldhippy said:

Not that I know of. If the dial has a minute ring have the hand the length so it is on it, you need to make sure the hand doesn't touch or rub the inside of the glass. You could google old watches that should give you ideas of the length of minute hands and there style.  

[Waggy]

@Knebothat's great advice and point well taken. However, when there are no obvious clues on the dial to point you in the right direction I was just thinking in those circumstances what rule of thumb should I follow as a starting point? I think in all cases, as you and @oldhippysuggest, the best way is to see what suits the dial in question rather than stick to a hard and fast rule. I guess I am exposing my background as an engineer and the internal conflict of wanting a solution in the shape of a formula rather than relying upon the aesthetics.

[tomh207]

38 minutes ago, Waggy said:

@Knebothat's great advice and point well taken. However, when there are no obvious clues on the dial to point you in the right direction I was just thinking in those circumstances what rule of thumb should I follow as a starting point? I think in all cases, as you and @oldhippysuggest, the best way is to see what suits the dial in question rather than stick to a hard and fast rule. I guess I am exposing my background as an engineer and the internal conflict of wanting a solution in the shape of a formula rather than relying upon the aesthetics.

It might be worth a look at Max Bill’s mathematical approach to design, he did design one of the most iconic watches for Junghans. If designing dial, hands and indices from scratch I might be thinking hour hand as 1.6xindex length, minute hand 1.6x hour hand length and see if I can fit it on the dial. The inner edge of the minute markers would need to be at the end of the minute hand with some tolerance, second hand no longer than going to the outer edge of the minute markers/indices. I too am from a technical background and kinda struggle too without guiding mathematics, at the end of the day it’s really what you think looks right. There are quite a few watches out there if you look at watch review channels that the hands have been pulled from the fullest parts bin with no thought to proportion. Hands need to be matched more to indices and markers to look even vaguely correct.

 

Tom