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This page was last updated on 10/08/14.

Mclennan Gearbox Upgrade

(below) Complete View of needed parts -- Micro-puller, Mclennan Gearbox, and 2.5X16mm Metric Socket Cap Screws.  (right) Pulling OEM motor shaft gear

(below) Use the "thin" shim and "Blue" Loktite when installing the Mclennan motor shaft gear.  I probably could have used "Red" Loktite, but wanted to still have the gear easily removable if I want to return to the OEM gearboxes.  If the "Blue" slips, then I'll use the "Red".  (right) I used a rat-tail file to enlarge the mounting holes on the gearbox case.  Also notice the 2.5X16mm socket cap screws in place that will be used to mount the motor to the new gearbox.  Using the metric screws eliminated the need to "re-tap the holes to 4-40 for "American Standard" screws.

(below) Another view of test fitting the Mclennan gearboxes to the worm.  (right) In order too get the Mclennan output shaft to fit properly into the Oldham coupler, I had to shorten the shaft by ~2mm or so with a Dremel and grinding wheel.  You really need to check often so that you do NOT shorten the shaft too much.  You can always cut more if it is too long, but once it is too short you will be out of luck and out of one Mclennan gearbox.

These last two images show that I need ~11.5mm of length on the output shaft and the right image shows how I filed one side of the brass tubing when making a sleeve for the Mclennan output shaft that is too small for the Oldham coupler.  This sleeve fits between the Oldham and the shaft with the flat side allowing the grub/set screws to lock down on the flat.