Editing Futaba linear switch

{{Infobox dswitch
| image name        = Futaba linear complicated vs simplified.jpg
| manufacturer      = [[Futaba]], [[Sejin Electron]]
| inventor          = 
| switch type       = Linear
| contact mechanism = [[Metal leaf]]
| product code      = 
| family            = Futaba linear switch
| keycap mount      = Custom cruciform
| switch mount      = [[Plate mount]], [[PCB mount]]
| lifetime          = 
| force graph       = 
| peak force        = 
}}

'''Futaba linear switch''' is a provisional term for a family of linear [[Plate mount|plate-mount]] switches typically with cylindrical shells. The term was selected to contrast the later "Futaba clicky switch", part of [[Futaba MA series]].

==Description==
Futaba linear switches all use stout, cylindrical legs that are threaded at the top and screw in. The switch terminals are separate internal parts that the legs make contact with inside the switch.

Most types are plate mount, and have a square-top cylindrical shell with truncated sides. In these types, the shell contains the whole switch, and the internal parts are held in by a base plug. The base plug for larger switches is secured solely by the legs, while the small type also has a clip on the base to secure it in addition to the legs.

A final known type has a square or rectangular cross section to the shell and is sealed shut.

The number of parts between Futaba switches varies. MD series "complicated linear" momentary switches comprises sixteen parts. The sealed switches share the short legs with MD series so are likely to have the same internals. MR and ML series switches have simplified internals of only nine and seven parts respectively.

Futaba linear switches have a lower travel than many other switches; travel ranges from around 2.7 to 3 mm across the switch range.

==George Risk versions==
Futaba linear switches were resold by George Risk as GRI products. MD series was resold as GRI KBM series, and ML series was resold as GRI KBM-LP.

==Variants==
===Futaba MD series===
{{Main|Futaba MD series}}

MD series "complicated linear" is the most common series, found in a number of forms including momentary and alternate action, upright and angled keystem, short and tall keystem, and illuminated. The single confirmed part number is MD-4PCS.<ref name="MD-4PCS" /> Different switch colour combinations exist, and these colours have not yet been decoded.

The switch has a non-uniform cruciform [[slider]] approximately 4.0 mm by 4.7 mm, with 1.2 mm wide arms, taking a 4 mm deep [[keycap]] stem. The distance between the plate and PCB is 12.7 mm.

The switch comprises 16 parts in total.

===Futaba MR series===
{{Main|Futaba MR-6C series}}

The simplified variant of the switch is physically compatible with the complicated variant, but uses only 9 parts: the complex contact assembly is replaced with bare contacts. The contacts remain distinct from the terminals, as with the complicated designs.

MR-6C series has been shown to contain the only type ever encountered; no documented evidence for MR types beyond MR-6C has yet been discovered. MR-6C itself is known only from a few types of equipment.

The switch actuates at mid travel, at around 60 cN.

===Futaba ML series===
{{Main|Futaba ML series}}

ML series represents a reduced-size version of MR series. Differences include the plate retention clips being attached to the base plug instead of the main shell, and the pins being offset towards the front of the switch.

[[Keycap mount]] compatibility is maintained with the larger switches.

===Sealed type===
{{main|Futaba sealed linear}}

The small square type appears to have similar internals to MD series, but the shell is square and the switch is sealed.

==Gallery==
<gallery widths=250 heights=187>
File:Futaba linear switches.jpg                           | Assorted switches
File:Futaba complicated linear.jpg                        | MD-4PCS switches
File:Futaba simplified linear.jpg                         | MR-6C switches
File:GRI KBM-LP -- assorted.jpg                           | GRI KBM-LP switches, likely Futaba/Sejin ML88
File:Futaba linear complicated vs simplified.jpg          | Complicated vs simplified — the difference is in the shape, not the colour
File:Futaba linear -- pin compatibility 1.jpg             | Pin compatibility between simplified and complicated variants
File:Futaba linear -- pin compatibility 2.jpg             | Pin compatibility
File:Futaba linear -- slider compatibility.jpg            | Slider compatibility
File:Futaba complicated vs low-profile linear (top).jpg   | Complicated and low-profile, top view
File:Futaba complicated vs low-profile linear (front).jpg | Complicated and low-profile, front view
File:BBC Micro Type 1 switches close-up.jpg               | MR-6C switches
File:BBC Micro Type 1 switches mounted.jpg                | MR-6C switches mounted into a keyboard
</gallery>

==References==
<references>
<ref name="MD-4PCS">Electronic Surplus — [http://www.electronicsurplus.com/futaba-md-4pcs-switch-p-b-no-keyboard-package-of-20FUTABA - MD-4PCS - Switch, P/B. NO Keyboard. Package of 20.]</ref>
</references>

==External links==
* Deskthority — [http://deskthority.net/photos-videos-f8/bunch-from-a-storage-unit-t4260.html Bunch from a storage unit]

[[Category:Futaba switches]]
[[Category:Linear switches]]
[[Category:Metal contact switches]]
[[Category:List of all keyboard switches]]