industrial garage door drive chain help needed

[Soundguy]

i'm repairing the middle bay roll up door at our shop.

has a pull chain that loops tot he bottom for the operator to pull on. has a large and small sprocket at the top.. the drive chain ( bike chain style etc)that runs the large and small sprocket is a hair bigger than 40, but smaller than 50.

any ideas.. i've never messed with garage doors like this.

any clue?

 

[Zebrafive]

Are you trying to ID the chain size?
Measure the distance between the side plates.
Roller diameter
Pitch (center to center of the roller pins)
Pin diameter (may not not need this, should be able to determine from above three dimensions)

WILD GUESS #428

 

[Soundguy]

That's my problem.. the chain is gone.

our ex mechanic took the chain off the garage bay. it was our only roll up bay on that building.. the other bays are an open drive in and an open pull thru.

he pulled the chain and we can't find it now, and the mechanic is long gone.

 

[Soundguy]

i just went up and go the small sprocket down.

I'm going to use my micrometer and caliper and do a good guestimate at reverse engineering those chain specs.

I have a list / chart for the pitch/diameter and plat spacings.. so will see what I can come up with.

thanks

 

[FrankR63]

My guess would be # 41 chain, that is a typical garage door chain, if not 48.
Frank

 

[Soundguy]

as soon as I can get some more measurements, I'll get it figured out

 

[unbidden]

Soundguy, is there any reference number on the sproket?

 

[Soundguy]

just went and cleaned the grime off the sprocket.. no numbers unfortunately.

I'll bring my calipers to work tomorrow and using the skrocket profiles as a guess will see what chain onthe chart may fit.

 

[Zebrafive]

Do you have other similar doors you can check that have the chain still intact?

 

[Soundguy]

i'm going to see if the door on the backside is this older style or not.

we had one door back there that was repaired and converted to a different drive.. it used 41 chain.. and that was too small .. we tried a scrap piece on this sprocket. pitch too short anyway..