350/351 Hermle Clock Movement

Hermle Clock Movement 350/351MVT NotesHermle IDTiming A BalanceWhat Happened?Why get a new Hermle?Other Names Used

Please view these information tabs to learn more about the 351-020 and other Hermle Clock Movement 350/351 units

Hermle clock 351 - 350 movement

Hermle clock 351 - 350 movement is a popular movement for the bracket style shelf mantle clock. Its basically the same clock movement as the 341 series except the plate size is 20mm bigger. Such as the 341-020 compared to the 351-020. Or the 340-020 compared to the 350-020 are the same unit, but the plate size. The 351 and 350 has larger outer plates overall. However they are not cross compatible because the winding arbors are not quite the same. So the dial on one will not fit a the other movement.

The movement

The 351 - 350 movement Hermle clock series has Westminster chime and with a 120mm square outer plate size. It comes in a pendulum version such as the 351-020 or the non pendulum balance wheel version like the 350-020. The balance kind just has a balance wheel more like a watch on the top of the movement that acts as the escapement.

This is beneficial in that it cant be out of beat and its fine to be off level. Also to move from here to there with no reset up of the clock. All of these Hermle clock 351 - 350 movements take a key size 8 to wind them up and the run time is 8 days in a single wind. These units are all spring driven with the exception being the 351-830 and 351-850. Those units are special as they have two springs and one weight for the center. Often the center weight will be split into two weights on a yoke.

The hammers

The hammer locations are variable on this series. The 5 hammer bottom strike 351-020 pendulum, or 350-020 balance units are the most used, the movement does not take much depth and so it can be put into a shallow clock case no problem. Same with the side strike 5 hammer units like the 351-030, it fits into a shallow depth well. Other hammer locations are the back 4 on one side and 4 on the other like the 351-050 unit. Then lastly as in the 351-060 unit you can have 5 hammers diagonally on the back instead.

The chime

This is a Westminster chime unit. What this means is it will play Westminster progressively as it runs through the quarter hours. On the top of the hour we get to celebrate with the entire song and then it will strike out whatever hour it is.

Placing an order

The movement come as the movement itself with its hand nut, comes with the suspension spring and leader if its the pendulum style Hermle clock 351 - 350 movement. The movement will come already oiled and ready to go. It will come with instructions by email, if you get stuck you can just ask us to help if you have issues beyond the instructions. This family has been working on clocks for literally 100 years, if you have a question, just ask us! And it does not matter if the clock movement is out of warranty either, even years after it does not matter. The factory warranty on this unit is 3 years.

  • Less cost than a cleaning in most cases
  • Should last 25-30 years, a repair would not
  • Easy to install, we can help if needed
  • Ships same day as order
Hermle Clock Movement 351
The content of this website is copyright by Clockworks and written by James Stoudenmire

Hermle Clock Movement Identification

Most important is the identification of the Hermle clock movement and it requires locating the numbers on the back plate of the movement itself. This can be done by removing access panels, sticking a phone inside and taking a picture, or even a mirror. Use any possible means to get the number of the Hermle clock movement. This information is not in the manual that came with the clock or on the wood case. On the back plate of the Hermle clock movement there are numbers such as 451-050 94 cm. These numbers indicate everything there is to know about that particular mechanical Hermle clock movement.

The content of this website is copyright by Clockworks and written by James Stoudenmire

Timing a balance clock movement

Balance Clock Movement Timing is done fairly easy. There are three types clock balance movement styles used after 1950. This section is for those balance units that do not have a platform escapement. The platform escapement can be read about in another section. These notes are only for the larger balance wheel in the top center of the clock movement. This was used by Urgos 6/ series and many of the Hermle clock movements. Such as 340-020 and 350-020. Out of these you have two styles, the old style and then the new style. The old style was used all through the 70's and 80's and 90's. Around this time that they switched to the new style on the Hermle units and by this time the Urgos units were out of production.

The old style

The old style is one with a round spring that goes up and down (Vertical). It goes in a circle around the center arbor of the balance wheel. In this style there is a slide arm with a tiny weight on the balance wheel itself. There is a + and - on the wheel. To speed up time go towards the plus sign. However this style is not always easy to regulate and can be very hard to get it perfect. The factory has special devices to make it perfect. However it’s not that easy on the customer end with this style balance. For this reason it has been improved upon during future manufacturing.

If you have the old style balance then your clock movement has some age to it. If this is the situation it is just best to replace the unit with the new one. Clockworks offers the movement brand new with the new style balance for less than the cost of a cleaning. Your clock movement has lasted you 25 years or more. In theory the new unit should last more than this with the improved aspects.

The new style

The units offered on this page all have the new and improved balance assemblies. Despite the change on the balance, these units are a direct fit and will install in the clock case the exact same way as the old unit. If the numbers match from the old unit to the numbers offered on this page, than the movement will be the exact same. It will be the same as it is now but brand new and with the improved balance.

The improved upon balance units have a different kind of hairspring (Horizontal). It will also have a screw to regulate it rather than a slider arm. The regulator screw is on the back of the movement near the balance. There is a + and - sign next to it meaning fast or slow. If the clock needs to be faster to keep time then the screw would be turned to the plus and opposite for slowing time.

Hermle clock movement exploded view
The content of this website is copyright by Clockworks and written by James Stoudenmire

Mechanical Clock Movement Wear

Mechanical clock movement wear after years go by because the oil turns solid. With age, the mechanical clock movement's oil solidifies and becomes black and sticky. By the time 20 or 30 years go by, the oil has solidified and is creating wear on the brass plates of the movement. So, when this happens, the clock movement will not run correctly. This is when the movement will need a cleaning or be replaced. Of course, a brand new movement is always your best option.

What wear and where

If you look at your old clock movement, you will see holes in the brass plates where there are small pivot arbors sticking into these holes. These pivots are what the gears of the clock ride upon and as the pivots spin in the solidified oil, this makes the holes oblong instead of round. With the pivot holes oblong, the holes are pinching the pivots and creating resistance in the gear train. With the solidified oil and the pinched pivots, the clock will eventually stop working or chiming.

Invisible clock movement wear

This wear takes place in the holes that are in the brass plates and is hard to identify sometimes. These holes in the brass plates become oblong instead of round and this pinches the pivot arbor going into it. Between this, and the solid oil, the clock ceases to function. To have this repaired is an expensive and long process. To have a mechanical movement serviced can cost two times as much or even three times the amount of the new one. However, once the movement starts having problems due to the oblong pivot holes, something will need to be done. The clock will never stay running otherwise.

The content of this website is copyright by Clockworks and written by James Stoudenmire

New Clock Movement Benefits

New clock movement benefits far outweigh the benefits of an overhaul. This section will explain why that is and what the best course of action is to get your clock working.

Getting the movement worked on

Clocks need to have fresh oil after 10 years or so. Then, after 20 or 30 years, a full break down of the movement is necessary. This is all well and good and can be done with the old movement. The movement will run for another 5 or 15 years with no issues but then it will be time to do it again. So obviously this is a new clock movement benefit.

The content of this website is copyright by Clockworks and written by James Stoudenmire

Hermle Clock Movement Aliases

Hermle produces clock movements but the use of aliases is quite prevalent. The movement could have a stamp with any name but really it will be made by Hermle. Some companies bought so many movements that they were able to get their name on the movement instead of Hermle. The following is only a partial list of names that could be on the clock movement.

The best Aliases in Disguise

Seth Thomas and Mason and Sullivan had not only their name, but also their own internal numbering system. Their stamp and number was on the movement instead of the Hermle number. Since it is not a Hermle number, the number would need to have a conversion to the real number. Correspondingly, this is done with the Mason and Sullivan chart, or the Seth Thomas conversion Chart. However the Seth Thomas chart is not very accurate, please see instructions on that page.

The content of this website is copyright by Clockworks and written by James Stoudenmire

Hermle Clock Movement

The numbers on the back plate of the 350 or 351 Hermle Clock Movement is everything one needs to get a replacement. If the numbers match then the movement will match. So if is says 350 or 351 and the rest of your numbers, it will be the correct one.


Hermle Clock Movement
Assistance = 800-381-7458

Hermle Clock Movement

  • Brand New and Original
  • Westminster Chime
  • Plate size 120 x 120mm
  • Spring Driven
  • Includes Leader
  • A fraction of the price of an overhaul
  • Should last 25-30 years, an overhaul would not
  • Instructions and expert support
  • Hermle Clock Movement of Germany

Clock Movements

350-020 350-020 Hermle clock movement
  • Balance Escapement
  • 33.2mm Hand shaft
  • 5 Hammer Below
  • Spring Driven
Front Side Back Explode
350-020: $330.00
351-020 351-020 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • Spring Driven
  • 5 Hammer Below
  • Factory oiled
Front Side Back Explode
351-020: $300.00$315.00
View Product
351-021 351-021 Hermle clock movement
  • Pendulum Unit
  • 27.6mm Hand shaft
  • 5 Hammer Below
  • Spring Driven
  • Factory oiled
Front Side Back Explode
351-021: $300.00
View Product

351-060 15cm

351-060 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • 5 Hammer Diagonal Back
  • Plate size 120 x 120mm
Front Side Side Back
351-060/15P: $338.00

351 030 351-030 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • 5 Hammer Side
  • Plate size 120 x 120mm
Front Side Back Explode
351-030: $300.00
View Product
351-031 351-031 Hermle clock movement
  • Pendulum Unit
  • 27.6mm Hand shaft
  • 5 Hammer Side
  • Westminster Chime
Front Side Back Explode
351-031: $300.00
View Product
351-050 351-050 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • 8 Hammer Back
  • Spring Driven
Front Side Back
351-050: $300.00
View Product
351-051 351-051 Hermle clock movement
  • Pendulum Unit
  • 27.6mm Hand shaft
  • 8 Hammer Back
  • Spring Driven
Front Side Back
351-051: $300.00
View Product

351-830 351-830 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • 5 Hammer Side
  • 2 Springs, 1 Weight
Front Side Back
351-830: $368.00
View Product
351-850 351-850 Hermle clock movement
  • Pendulum Unit
  • 33.2mm Hand shaft
  • 8 Hammer Back
  • 2 Springs, 1 Weight
Front Side Back Explode
351-850: $368.00$399.00
View Product

350-060

351-060 Hermle clock movement
  • Balance Escapement
  • 33.2mm Hand shaft
  • 5 Hammer Diagonal Back
Front Side Back Explode
350-060: $330.00

Hermle Clock Movement Directory Explanation

Above all, a Hermle Clock Movement Directory is to get to the correct page that contains the proper clock movement. This is an important first step when ordering a new clock movement. Thus, Hermle mechanical movements have numbers on the back plate starting with the below few numbers. Then a dash (-) follows and then some more numbers. For example: 340-020 131-070 1161-853 351-020 and so forth. So, if the clock says something like 1161-053 drop the second half and click the 1161 button below. Then this will bring up the page where the 1161-053 is as well as the rest of the 1161 series.

Hermle Clock Movement Directory

HermleHermle Clock Movement Directory, Number starts with.....

Mechanical Clock Movement Identification by Clockworks.com
Hermle Clock Movements
Mechanical Clock Movement Identification by Clockworks.com

If Not Listed

If the old Hermle clock movement is not found on these pages we may still have it as a conversion or we may be able to create it out of what exists. However, we need to know the movement number. So please email your movement number. Of course a picture of the back plate is also helpful. Moreover, if your movement numbers do not look like the Hermle movement numbers it may be made by someone else. Additionally, the mechanical movement identification page will assist you with determining who made the clock. In any event, this is for post WW2 modern mechanical clock movements made in Germany only.