Apart from widths, many customers over the years have asked me about spring bar diameters.
Spring Bar Widths
Most of you would know spring bars attach to watch lugs to hold the strap or bracelet in-place and come in various widths to suit your particular watch. Standard or ‘quick fit’ / ‘quick release’ are also optional. Quick release have vastly improved over the years and therefore i recommend fitting quick release over standard spring bars – easy to fit and remove without scratching your watch or stabbing yourself with a spring bar tool.
18mm, 20mm and 20mm even widths are still the the most common and lots of watches also have odd sizes like 19mm, 21mm and 23mm spring bars.
Always measure between the lug of your watch with vernier calipers to determine correct ‘lug width’.
Spring Bar Diameters
The diameter of the spring bar is also important and needs to suit the strap or bracelet lug hole.
Spring bar diameter sizes are generally 1.3mm, 1.5mm, 1.8mm and can even be up to 2.5mm. 1.5mm is standard and most common for straps. 1.3mm spring bars are mainly found on less expensive straps. Not because they are inferior quality just that they may be a few cents cheaper for the supplier. 1.3mm is also used when distance to case was designed for use with a thin bracelet. In this case, a 1.3mm spring bar attached to a leather strap may make it possible to fit. One of my vintage TV Seiko watches has this exact problem. The watch originally came with a very thin bracelet with lug holes close to case – see the exact watch on the video gallery ‘Noosa Blue Leather Watch Strap | Vintage Seiko TV Case’.
Diameters over 1.8mm would be a ‘custom’ strap design or order.
Why? you ask…If you look at your watch lug and measure the distance between lug hole and case theres never a lot of room to fit a strap without rubbing against the case. If you go bigger without measuring particularly in a custom order where the customer may not have taken the case to lug hole distance into account, problems will occur.
For bracelets you may need to find out or measure existing diameter so that the spring bars fit perfectly. Not too tight and not too loose. Having said that, you could also just fit the standard size 1.5mm, which will be a good choice for the majority of watches.
So should you fit a ‘thicker’ spring bar if your leather watch strap lug feels a bit sloppy?
Most of the time, no! If you do, the leather may not fit between lug and case, stretch with the increased size and eventually tear at the lug. When the watch is fitted to your wrist any ‘sloppyness’ (is that even a word Rob?) at the lug will be taken up by the fastening of the watch anyway.
In my opinion, it is allways best to stick to 1.5mm diameter spring bars for leather straps and at the very most 1.8mm.
Anything over these sizes probably won’t even fit through the lug hole unless force is applied and that is not going to end well.
Be sure to read my handy guide on how to fit a leather strap to your watch – Here
Hope this helps.
Rob – LeatherStraps.com.au
