4 way restrictor for Qanba Q1 joystick

[UDb23]

Some months ago I bought a Qanba Q1 (PS3 & PC) Joystick to use with Mame games in Retropie.
Of course it's not a "professional" arcade stick but it makes a huge difference vs usual gamepads and I'm quite happy with it.

Joystick includes different restrictor gates you can mount but unfortunately no 4 way gate. Qanba seems not offering it, not even as an option or spare part.

Early arcade games (e.g. PACMAN, PENGO) were using 4 ways sticks so you can't really play them well with a standard 8 way stick.

By searching on the web I found out that Sanwa does provide 4/8 way gates for their sticks and the connecting holes looked almost identical to those on the Q1 gates.
I just got one of these (Sanwa GT - 8F Square Restrictor Gate 4/8 Way For JLF Series Joystick
) from ebay and, with minimal and easy work, it can be adapted to work with the Q1.

Thought it could be useful to others sharing how to.

The Q1 opens easily just by removing 6 screw on the bottom.

As you can see in the picture above the Sanwa gate does not fit due to top and left areas highlighted in green, that are larger than the original. Apart from that, all positioning holes and clip blockers fit correctly.
Easy solution: you just file those exceeding areas !
Result fits perfectly as you can see in the image below (shows also original 8 way gate as a comparison).

A very clever function of the Sanwa gate is that you can switch it from 4 ways (diamond) to 8 ways (rounded square), and back, by just turning the internal plastic ring.