Crank Extension for Milgard Tuscany Casement Window

A quick learner from California says:
Will 39-357 fit the Milgard Tuscany casement window. I'd like to extend the crank 6-10 inches. Will I be able to attach two 39-357 extensions together along with 39-121 Crank Handle?
Profile picture of Tom
Tom from SWISCO responded:
I'm not sure, I'm not familiar with what operators the Milgard Tuscany casement windows use. What is the size of your current spline? The 39-537 and 39-121 both accept a 5/16" spline, so they can work together, I just don't know if they will work for you.
A quick learner from Pleasanton says:
What's the proper way to measure a spline? I can just take a caliper and measure from tooth to tooth. I'll try to do that tonight.

BTW. How do the extensions lock onto the handle? Would I be able to lock the extension to the casement window spline as is done with the current handle (set screw)?
Profile picture of Tom
Tom from SWISCO responded:
Yes, try that. Also measure the diameter of the hole in the handle. If you want, you can take a couple pictures of your existing operator and we can suggest something from that.

The extensions lock in the same was as handles. You place it over the spline and then tighten it with the set screw. The handle then attaches to the extension in the same way.
A quick learner from Pleasanton says:
It measures 5/16" from spline tooth to spline tooth. The narrow dimension (without spline) is 1/4". Attached is a picture of the operator with handle removed.
User submitted photo of their window operator.
Profile picture of Dave Sr.
Dave Sr. from SWISCO responded:
Looking at your photo, it appears that you have the 39-375 Truth folding handle, which uses the 11/32" spline. For extensions, you would need to use the 39-157 which is 4" long or the 39-337 which is 2" long. Take a look and see what you think.
A quick learner says:
Hellp Quick Learner,

Did it worked for you ?

I have exactly the same window.

My other question is : One side ( female side ) of this extension does not have any splines. So how will that attach to the window side of things ?
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)