- Joined
- Jan 18, 2013
- Messages
- 34
Hello all. This gear repair might be of help to some folk.
The Mazak bevel gear, part 9-48B, in the forward-reverse gearbox on my clone Atlas 10F was missing a tooth. Yes, the big expensive gear!
The difficulty of mending Mazak is well documented. Fortunately I had a spare bevel gear, part 9-49A, so after some thought I decided to cannibalise this gear and replace the input to the F-R gearbox. The attached photos show how I repaired the input gear.
I dismantled the existing input shaft and carefully measured the dimensions of part 9-48B.
I centred the steel input shaft (part 9-52A) in a 4 jaw chuck, checked for concentricity, found 4 thou TIR and so trued up the diameter that mates with part 9-48B. I also put centres in each end of the shaft and drilled and tapped one end to assist with assembly.
From 1 inch stock brass bar I machined a bush with 2 internal diameters to suit the steel input shaft 9-52A and the modified bevel Mazak gear 9-49A. I mounted part 9-49A on an expanding mandrel and modified it to suit the brass bush.
The Mazak gear head was a hand press fit in the brass bush and steel shaft had about one and a half thou interference in the bush bore. The steel shaft was pressed in and the Mazak gear head was secured with Loctite.
The F-R gearbox now has gears with a full complement of teeth! Where there is a will there is usually a way.
The Mazak bevel gear, part 9-48B, in the forward-reverse gearbox on my clone Atlas 10F was missing a tooth. Yes, the big expensive gear!
The difficulty of mending Mazak is well documented. Fortunately I had a spare bevel gear, part 9-49A, so after some thought I decided to cannibalise this gear and replace the input to the F-R gearbox. The attached photos show how I repaired the input gear.
I dismantled the existing input shaft and carefully measured the dimensions of part 9-48B.
I centred the steel input shaft (part 9-52A) in a 4 jaw chuck, checked for concentricity, found 4 thou TIR and so trued up the diameter that mates with part 9-48B. I also put centres in each end of the shaft and drilled and tapped one end to assist with assembly.
From 1 inch stock brass bar I machined a bush with 2 internal diameters to suit the steel input shaft 9-52A and the modified bevel Mazak gear 9-49A. I mounted part 9-49A on an expanding mandrel and modified it to suit the brass bush.
The Mazak gear head was a hand press fit in the brass bush and steel shaft had about one and a half thou interference in the bush bore. The steel shaft was pressed in and the Mazak gear head was secured with Loctite.
The F-R gearbox now has gears with a full complement of teeth! Where there is a will there is usually a way.
"crunch " 
.... things stopped moving on their own .. hit the kill switch PDQ found bits of the fwd/reverse box collet sleeve on the mounting bench / table.
