# 9-48B Gear Repair for Atlas 10F



## oldscouser (Jan 29, 2020)

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.


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## Round in circles (Aug 3, 2020)

Thanks for posting that old Scouser .
This evening I put my cross slide  under power  for a mind numbing job of winding off almost 1/4 of alu ,  it worked well  till the slide was at it's max out travel  , I started to pull the release  when  "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. 

I'll be be stripping it down tomorrow .. I may need your adaptation as well as a new collet ( 3D print collet  in ABS as trial temporary  solution ??? )


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## wa5cab (Aug 3, 2020)

I'm not sure what Mazak is although I think that I have seen the word elsewhere.  But the die-case parts on the various Atlas machines are made of Zamak V.


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