There’s been a lot of threads and talk about o-rings and their alternatives lately. I thought I’d make a centralized place to put this info so it’s easier to reference later. Please let me know if you’d like more information to be added to the OP or just add it to the thread.
TABLE OF CONTENTS
- What are o-rings and what are they used for? (#post_what)
- What are some typical o-ring dimensions? (#post_dim)
- Are there any reviews/discussions on o-rings? (#post_rev)
- Where can I buy o-rings/dental bands/soft-landing pads? (#post_buy)
What are o-rings and what are they for?
O-rings (in keyboarding terms) are used to dampen sound and soften the bottom-out of the keystroke on switches in mechanical keyboards. I like the WASDKeyboards explanation of o-rings. This explanation can be applied to soft-landing pads and the dental band mod:
“ "Bottoming out" is a term used to describe when a key stroke is pressed all the way down where the stem of the switch hits the inside of the switch casing. This causes a "clack" from the collision on mechanical keyboards. Switch sound dampeners are soft rubber O-rings that can be installed onto every single keycap stem to cushion the landing of the switch by stopping the key stroke just short of the point of bottoming out. This also very slightly reduces the max travel distance of the switch.”
(Quote from WASDKeyboard (http://www.wasdkeyboards.com/index.php/products/keyboard-accessories/cherry-mx-rubber-o-ring-switch-dampeners-125pcs.html#ad-image-0))
O-rings can be used on MX and Alps switch stems. There are other alternatives as well: soft-landing pads and dental bands. Soft landing pads can be used with MX stems (and maybe Alps?). Typically, dental bands are used for Topre stems.
Dental rubber bands or dental bands are the rubber bands that are used with braces from orthodontists. Soft-landing pads are little squares of plastic which function like o-rings have a different reduction in travel versus the o-rings.
O-rings and dental bands are typically made from nitrile rubber (http://en.wikipedia.org/wiki/Nitrile_rubber) or EPDM ruber (http://en.wikipedia.org/wiki/EPDM_rubber). I’m not sure what the soft landing pads are made from, though it probably is a synthetic rubber of some sort. Ripster (http://i.imgur.com/z05zV.jpg) guesses that the landing pads are made from Sorbothane (http://en.wikipedia.org/wiki/Sorbothane).
Anyways, these rubbers/polymers have different hardnesses (aka how soft or hard they might be) which are measured with the shore durometer (http://en.wikipedia.org/wiki/Shore_durometer) scale. For layman’s terms for understanding shore durometer, I like this chart from smooth-on (http://www.smooth-on.com/Durometer-Shore-Ha/c1370/index.html).
More
(http://www.smooth-on.com/images/durometer_with_logo_small_580.jpg)
(Shore durometer scale with comparison to everyday objects)
What are some typical o-ring dimensions?
Typical o-ring dimensions that will fit MX and Alps caps:
- Inner Diameter = .1875 (3/16”) inches or 4.76mm
- Outer Diameter = .3125 (5/16”) inches or 7.94mm
- Thickness = ranges anything from 0.3937 in or 1 mm to .09375 in (3/32”) or 2.381 mm will depend on how much travel reduction you’d like
- Hardness = 30A to 80A
(Numbers from WhiteFireDragon’s GB (http://geekhack.org/index.php?topic=25714.0))
Typical dental band dimensions that will fit Topre caps:
- Inner Diameter = .1875 inches (3/16”) or 4.76mm
- Hardness = 30A to 80A
(Numbers from Mikelanding’s picture) (http://geekhack.org/index.php?topic=34972.0)
**Note, o-rings used for MX/Alps will not fit Topre caps due to the tolerances. See this discussion from huttala and longweight. (http://geekhack.org/index.php?topic=44692.msg931929#msg931929)
Are there any reviews/discussions on o-rings?
- CPTBadAss’ review (http://geekhack.org/index.php?topic=40227.0) (Shameless self promo :P)
- WhiteFireDragon’s writeup (http://geekhack.org/index.php?topic=25612.0)
- swill's measurements about keycap profiles and travel distance (http://geekhack.org/index.php?topic=53174.msg1186392#msg1186392)
- A discussion on o-rings (http://geekhack.org/index.php?topic=53069.0) (I like swill’s post here)
- An older discussion on DeskThority (http://deskthority.net/workshop-f7/o-ring-modification-t2219.html)
- WhiteFireDragon’s GB (http://geekhack.org/index.php?topic=25714.0)
- Sorda claims this is the first o-ring mod thread! (http://geekhack.org/index.php?topic=5450.0)
How do I install o-rings/soft landing pads/dental bands?
- My review has some pictures for o-rings and soft landing pads on MX stems (http://geekhack.org/index.php?topic=40227.0)
- Ripster’s guide has pictures for installing dental bands on MX and Topre stems(same process as o-rings) (http://imgur.com/a/eMUXT)
- WFD’s pictures for o-rings on Alps stems (http://geekhack.org/index.php?topic=25789.msg486276#msg486276)
- Mikelanding (http://geekhack.org/index.php?topic=34972.0) and huttala (http://geekhack.org/index.php?topic=44692.5) show pictures of dental bands on Topre caps
- Spicebar's writeup for dental band modding a F660C (http://geekhack.org/index.php?topic=49046.0)
Where can I buy o-rings/dental bands/soft-landing pads?
- WASDKeyboards (http://www.wasdkeyboards.com/index.php/products/keyboard-accessories/cherry-mx-rubber-o-ring-switch-dampeners-125pcs.html#ad-image-0)
- Max Keyboards (http://www.maxkeyboard.com/cherry-mx-rubber-o-ring-dampeners-110pcs.html)
- Buna-N 3/16” 50A from Amazon (http://www.amazon.com/dp/B0051XWXCE/ref=biss_dp_t_asn)
- Buna-N O-rings from Scientific Instrument Surfaces (http://www.sisweb.com/vacuum/o-rings/buna.htm)
- Imsto o-rings (http://imsto.cn/index.php?route=product/product&path=61&product_id=58)
- Mcmaster-Carr (http://www.mcmaster.com/#as568a-o-rings/=qfp841
h) - eBay Dental Bands example from Huttala (http://www.ebay.com/itm/3-16-Medium-3-5oz-NEON-ORTHODONTIC-ELASTIC-BRACES-DENTAL-RUBBER-BANDS-/140937069342?pt=LH_DefaultDomain_0&hash=item20d081031e)
You can also try making your own like o2dazone (http://geekhack.org/index.php?topic=40582.0) did.
Let me know what else to be added to this or what you like to see.