Hi Alembicers.
Has anyone changed the stock Schallers for lightweight tuners.
I can't seem to find any that fit the holes.
Any help appreciated.Jim

Schaller themselves make lightweight versions of their regular tuners. Depending on the location of the mounting tab, one of these should work for you:

https://schaller.info/en/machine-heads/292/m4-90-light?c=53
https://schaller.info/en/machine-heads/290/m4-180-light?c=53

I do not believe that they are a direct replacement.   They require a larger hole in the headstock.    I would love to find a set of the M4 90's that fit my 1975 Alembic bass.  I looked into these and were disappointed that they don't fit.

They do require a larger hole than the earlier M4's. An experienced tech can widen the holes.

I got my first bass in 81, a secondhand Japanese that was upgraded with Schaller M4s, and they appear to be the same shaft size that came on my 88 Spoiler (that I bought in 02). So perhaps if Chris' bass is a later vintage, the current ones may fit.

Hipshot makes two versions of their Ultralite Bass Tuners, one for 9/16" holes, and one for 11/16" holes.  And they are great tuners.

Bill, tgo

Hi, I bought these schaller M4 90 light for my '77 Series 1 and they were too big (see attached link). The bore size of the newer light M4 is 14mm-9/16
I just removed the original 1977 version M4, and the measured hole size is 12mm. There will be some boring out required if I ever install a 9/16 size tuner on my '77.
https://www.emma-music.com/-schaller,us,4,SCH-503450-L.cfm