Mainspring Pliers remain popular for punching and cutting thin steel as well as collectible pieces. This is part of a family of guides about old precision tools. To access the current Index for all these guides, please click on: Back to Index Guide.
Whether you are someone starting a collection, an experienced Master Watchmaker, a Jeweler, a dealer or just someone who loves the craftsmanship that goes into beautiful precision tools... you might find some useful information in this guide.
FUNCTION
These pliers were manufactured to help service watch mainsprings and their barrels. Most of these old tools are of robust construction using quality metals properly tempered. They perform three main functions:
a) Punch holes on mainsprings
b) Punch a hook on the wall of a mainspring barrel
c) Cut mainsprings to size
Not all models perform all the functions and some of these tools were transformed over the years to perform other functions.
The above model has all three functions in addition to having features found in higher end models such as spring loaded handles, lock, heavier nickelled, etc. The blades are high quality hardened steel pieces, removable and razor sharp. They are specially placed (some have thin metal shims) at an angle such that keeps the edges barely touching to ensure the mainspring does not slip while cutting it. The fulcrum has to be in top shape to minimize lateral movement for this type of operation.
The picture on the right shows a detail of the testing plate. This is an important test to assess how well the tool performs. There are two rows of holes in this piece of tin sheet, one without the chips (the lower row) and another with the chips still attached (upper row). This tool has punches of different shapes: a half disc ("quarter moon") punch, two different rectangular punches and a circular punch. The far right holes are for the barrel hook and they show a chip still attached by the shortest side. There is also a cut made by the blades on the upper right corner to make sure the blades cut clean and they do not slip.
The picture on the left shows a detail of the punches. Four for the flat anvil (underneath the "bridge" for seating the regulating screw) to punch through the mainspring and the one on the tip over the curved anvil to create a hook on the mainspring barrel.
MODELS
A great variety of models for these tools were produced and still many remain today. Due to limitations in the number of pictures available to be posted in eBay Guides, we are listing below some common and few uncommon models that can still show up in the marketplace and collections. The golden piece of tin sheet shown in some of the pictures is a "performance test" to provide an indication of how effectively the punches work.
Model with with barrel hook punch and mainspring punches.
Model with graduated mainspring punches. One round and three rectangular.
Single punch for mainspring and barrel hook model.
This model has mainspring punches, barrel hook punch and cutter; an all in one model with handle spring and clasp. This is an old Swiss Made top of the line model with mainspring punches of half circle, round and rectangular shapes.
Bracelet mainspring barrel hook punch. This punch has been manufactured by Hammel and Riglander Co. (HR) with English steel and rotating "turret". The turret has different punches that can be locked in position.
CHALLENGES
Some of the old tools currently available have been carefully maintained and used. In spite of their many years of service, some would still be able to perform reasonably well over even a longer period of time. However most may show some signs of wear, neglect or breakage. The following pictures show some of the most common challenges found in this type of tools:
Rust may not be always evident in these tools as some were heavily nickelled and very rarely the punches are loosened to remove the rust that's out of sight. It is a concern nevertheless, since some of the punches may need resharpening and a rusted punch might prove a significant challenge to loosen up. As the picture above indicates, some punches may not be straight, some may have broken tips or need sharpening.
Punches were generally not tempered uniformly. In some models, they were tempered in a longitudinal gradient so that the hardest portion is at the tip and gradually it becomes less hard towards the top. A bent punch might not be correctly aligned with the hole in the anvil and therefore it may not cut or if it cuts, it may deform the corresponding hole by wearing it unevenly. A bent punch might be corrected by carefully adjusting it. However, striking it with a hammer may break it. The following steps generally answer well to fix this problem:
a) Take the punch out of the pliers (penetrating oil and lightly tapping with a brass hammer might help)
b) Anneal it (and test hardness afterwards to make sure the annealing is complete)
c) Straighten it and test it in the pliers until proper alignment with the corresponding hole in the anvil is achieved
d) Re-sharpen the tip (if necessary)
e) Adjust the locking hole (if necessary) and test with the locking screw
f) Properly temper it (tip in first in cold oil moving it down gently to achieve a gradient temper)
g) Replace it in the pliers and firmly lock it in
h) Make a test with a piece of tin sheet to check proper alignment
Punches treated in this way will keep a keen edge for a long time and they will only require an occasional touch with a hard Arkansas oil stone to keep them sharp.
Some punches may be replacements of a lesser steel quality or not properly tempered to punch a hole on steel. Punches of different lengths are not a concern in itself, as long as the tip still has the proper temper grade and it is sharp.
This anvil shows the portion used by the barrel hook punch broken off and some of the other holes deformed and rusted. A broken, cracked or deformed anvil is a common problem that's very hard to solve practically. Another common challenge is that of poor maintenance: if you find an anvil broken that may be the tell tale of other problems as the tool might also have an issue on another part.
TIPS
Simple tips to acquire, maintain and use these tools:
Before acquiring any of these tools, ask questions about the common challenges listed above and check for signs that may indicate the condition and quality of the tool.
The punches "performance test" is simply made with a piece of tin can used to show how the punches work. The impression left in the tin sheet tells if the punches are sharp or not, if they were modified, etc. Some of the punches may have been reshaped for specific tasks, and most commonly, the barrel hook punch may have been changed to punch a hole (with the chip hanging from a side) instead of creating a hook (with the chip hanging from one end). Not a problem in itself, though it may be good to ask. Before acquiring any of these tools, it is prudent to see pictures of the punches impressions (with the chips still attached and without, with the two rows of holes as in the pictures above), as it is the best way to know whether the tool works or not before having it in your hands.
The mainspring steel should be thoroughly annealed before using these tools and the thickness of the material should be appropriate for the type of tool used. The cutters may chip and the punches may break if attempting to cut hardened steel or material that is too thick. Heating to a greenish color may be enough, check hardness aftwerwards to ensure is is adequatly annealed as some steels are harder than others.
A drop of oil on the punches before using the tool may make them cut better and will keep the tool in top shape.
No punch will make such a clean hole that would require no further work. Carefully cut out the chip produced by the punch, file and stone down any burrs, then clean the spring with a No. 0 emery buff running lengthwise to make sure the grain is straight and parallel to the edges of the spring.
Make sure the hook is facing the correct way and in the correct position before punching a hook in the mainspring barrel. The length and angle of the hook should be similar to the original.
If seldom used, keep it covered with a thin coat of bee's wax or grease to minimize the formation of rust.
