I have measured my fast disintegrating pads, as being 4mm thick. The base pad is 65mm in diameter and the lid bumper 15mm in diameter. If anyone disagrees with those measurements I'd be obliged for your input.

Any input into what is acceptable as a replacement would be most welcome. I have written to Jack Christensen but he doesn't respond.

Finally I see that red o-rings are easily available but not so white ones. Any help in finding one would be much appreciated.

The Curta engineering drawings are available at http://www.museummura.li/content.aspx?nid=5051&groupnr=5051

I checked them and found for the Curta Type 1 the assembly drawing is Curta_1_10228.pdf. The size of the base pad (Curta_1_10130.pdf) is 54mm in diameter and 3mm in thickness. The lid bumper (Curta_1_10131.pdf) is 15mm in diameter and 15.5mm tall with a 10mm hole cut 7mm down in one end

For the Curta Type 2 the assembly drawings are Curta_2_2550_sw.pdf and Curta_2_2551_sw.pdf. The base pad has two drawings (Curta_2_2183_410634_sw.pdf and Curta_2_2183_sw.pdf). They both have a diameter of 66mm. One has a 4mm thickness while the other has a 5mm thickness. The lid bumper (Curta_2_2182_sw.pdf) has an 18mm diameter at the bottom and 15mm diameter at the top and is 21mm tall with a 16mm diameter hole cut 4mm into the bottom.

As I do not own a Curta, acceptable replacements would be better addressed by the other members here than myself.

here you can download all drawings...

- part #2183 the diameter is 66mm / 5mm high
- part #410634 the diameter is 66mm /4mm high (I assume for the plastic canister)
- part #2182 (the upper rubber) the diameter 18mm / 21mm high

mwu wrote:

The Curta engineering drawings are available at http://www.museummura.li/content.aspx?nid=5051&groupnr=5051 I checked them and found for the Curta Type 1 the assembly drawing is Curta_1_10228.pdf. The size of the base pad (Curta_1_10130.pdf) is 54mm in diameter and 3mm in thickness. The lid bumper (Curta_1_10131.pdf) is 15mm in diameter and 15.5mm tall with a 10mm hole cut 7mm down in one end For the Curta Type 2 the assembly drawings are Curta_2_2550_sw.pdf and Curta_2_2551_sw.pdf. The base pad has two drawings (Curta_2_2183_410634_sw.pdf and Curta_2_2183_sw.pdf). They both have a diameter of 66mm. One has a 4mm thickness while the other has a 5mm thickness. The lid bumper (Curta_2_2182_sw.pdf) has an 18mm diameter at the bottom and 15mm diameter at the top and is 21mm tall with a 16mm diameter hole cut 4mm into the bottom. As I do not own a Curta, acceptable replacements would be better addressed by the other members here than myself.

Thank you so much that is very helpful.......The material is Moosgummi - grau, grey foam rubber.
The drawing Curta_2_2182_sw.pdf is for the Haltezapfen (retaining spigot?) and is made of aluminum. the rubber bumper fits inside that. The depth of the retaining hole is 16mm in diam x 4mm deep but according to the pictures above they seem to vary in height