Curta Calculator
Cleaning & Repair Service

Home   Curtas For Sale   Rally Products   Other Services   Ordering   Links   History


Professional Cleaning and Repair of the
CURTA Type I and Type II Mechanical Calculator

CURTA CALCULATOR CLEANING and REPAIR SERVICE
Photo courtesy of Rick Furr       Please visit his CURTA Calculator Page



Since 1986, Timewise has provided complete Curta maintenance
and repair service to the Curta enthusiasts community.
Timewise is recognized worldwide as the premier service provider
for the Curta calculator.


This page last updated Thursday, November 5, 2015



In addition to servicing rally computers and rally clocks, Timewise also provides professional cleaning, adjustment and repair service for Curta Type I and Type II mechanical calculators.

The Curta calculator requires regular maintenance to prevent acummulating dirt and dust from binding the mechanism. To complicate matters, volatile compounds in the original lubricating oils can evaporate, leaving behind a sticky residue that impedes the movement of sliding gears and levers. Such conditions often result in the application of excessive forces to operate the instrument. A Curta whose lubricating oils have hardened significantly during long term storage will be damaged when the crank is turned. Repair of the instrument is then necessary.

The demand for cleaning and repair service of the the Curta is increasing because of recent print and broadcast articles extolling the virtues of these semi-antique mechanical marvels. Curta owners often are reminded of their old keepsakes and retrieve them from storage trunks and desk drawers. Many of these "found" Curtas are then auctioned on eBay to collectors who want the instrument restored to a clean and "as new" operable condition.

The Curta is also an essential tool in vintage car rallies, where extreme dust and temperature conditions exist. Yearly cleaning is often required to keep the instrument operating flawlessly.


A Curta submitted to Timewise for service will be cleaned, repaired, adjusted, and lubricated to factory specifications. After the service is completed, full functionality of the Curta will be confirmed, and the unit will be returned to the owner.

A Curta submitted to Timewise simply for service diagnostics will incurr a $35 charge, plus return shipping. The Curta will not be returned until the service diagnostic charge and return shipping cost is paid in full.

Always contact Timewise before sending a Curta for service. Details of scheduling the service work can be dicussed at that time. Many repair "only" service can be accomplished in short order, whereas a thorough cleaning and lubrication will extend the service time dramatically. Significant time is needed to achieve a complete and full restoration. Turn around time for cleaning a Curta varies, and can be many months depending on scheduling and work load.

The work performed is thorough and of very high quality. Timewise carries an extensive assortment of original Contina factory parts for servicing the Curta. In addition, original factory tools and component clamping fixtures are used in accordance with procedures and workmanship standards set forth by Contina AG.

A Curta submitted for a cleaning will be thoroughly checked for internal damage. Should this initial inspection disclose damaged or missing components, replacement part costs will be quoted before cleaning is performed. Repair parts will be, whenever possible, NOS (new, old stock) factory original components.

Typically, cleaning a Curta involves complete disassembly of the upper carriage and partial disassembly of the main body. The main body will be disassembled further if something internal is bent, out of adjustment, or broken. Following the disassembly, all components are cleaned using appropriate solvents. The Curta is then re-assembled and lubricated to factory standards. The oils and greases used are specifically developed for fine watches and other precise mechanical movements, and are improved formulations of the original factory lubricants.

Charges for a simple cleaning and lubrication of a Curta Type I typically range from $225 to $275, including consumables. Costs for a simple cleaning of a Type II typically range from $265 to $315. As you might expect, the charge is dependent on the time and effort needed to remove the old dried oils and accumulated dirt, as well as the difficulty of disassembly due to corrosion or previous poor workmanship. If the Curta is in such poor condition that disassembly is extremely difficult, the charges may be higher. If your Curta has been serviced within the last twenty years, the cleaning costs will possibly be lower. When additional labor time is needed to complete required repairs, the extra work is charged at an hourly rate.

Complete and thorough servicing of a very dirty and "gummed up" Curta Type I will cost $310. Such service performed on a Type II will cost $350. This level of service involves disassembly of every part and subassembly, including the entire lower half of the machine. Each and every component is ultrasonically scrubbed and individually inspected. The tens carry mechanisms, the tens unit, and the results and counter digit tens overflow pins are all checked and adjusted. The clearing plate shims and the zero-position roller pressure are measured and adjusted as necessary. The setting digit slider springs and pressure discs are also adjusted to equalize the feel of each slider. The main shaft will be checked for "trueness" and corrected as necessary. These adjustments, and many more, correct problems due to wear and material stress. If the Curta is in such poor condition that disassembly is extremely difficult, the charges may be higher.

If it is determined that replacement parts are needed, or significant damage is found that requires unusual machining or repair of existing parts, the owner will be informed of the problems encountered and approval of the extra labor and/or replacement parts expense will be required before the work continues.

When a cleaning is scheduled, repair diagnostic charges are included in the cleaning service (except when the fault is so difficult to locate that it is revealed only after a complete cleaning and re-assembly). If a cleaning is not scheduled, repair diagnostic charges are $35. If the Curta is to be repaired without being cleaned, labor charges for replacing a broken or damaged part are in addition to the diagnostic charges and the replacement parts cost. This is due to the required disassembly/re-assembly time. Such labor charges can range from $35 to $70, depending on the level of disassembly needed to reach the defective part.

If a cleaning is being performed at the same time as a repair, there is generally no repair labor charge. This is simply because replacement parts would be installed in place of the damaged items during the cleaning procedure. On the other hand, there are some repairs that require a special installation procedure whether or not a cleaning is being performed (e.g., a clearing lever plunger replacement). Such repairs always have an installation labor charge. Also, some repairs require drilling out rivets which result in additional costs to replace those rivets.

If the Curta requires such extensive repairs that the owner wishes not to have the work completed, or where a cleaning service is contra-indicated simply because the Curta is in very poor condition, the instrument will be returned in its original condition and the owner is only asked to pay diagnostic charges and return shipping costs.

Turn around time for repair of a Curta varies, and can be up to several months depending on scheduling and work load. Please call or email before sending a Curta for service. Details of scheduling the service work can be dicussed at that time. Many repairs "only" can be accomplished in short order, whereas a thorough cleaning and lubrication will extend the service time dramatically. Significant service time is needed to achieve a complete and full restoration. Contact Timewise for more information.




Home   Curtas For Sale   Rally Products   Other Services   Ordering   Links   History

Timewise
32 Old Barn Road
Hawthorn Woods, Illinois 60047
United States
847-550-5052
Email Jack Christensen at: curta.info@gmail.com

This page last updated Wednesday, July 20 , 2016