The 9x20 Mods Thread

savarin

savarin

Active User
H-M Supporter Gold Member
Joined
Aug 22, 2012
Messages
4,260
  • My 9x20 has a couple of mods including a qctp and 4 bolt clamp for the top/compound slide.
    I have noticed there is still a fair bit of flex under some conditions, parting being one.
    The fixing bolt for the qctp is still the original skinny one but with spacers.
    I will be drilling and tapping the compound to take the 14mm fixing bolt which I hope will remove a fair bit of flex, making a delrin cross slide nut to help remove the excessive backlash currently there as another must be done fix.
    I'm considering making the pritkin donut as I believe this is another possible cure for flex.
    Has anyone here made one of these and how does it perform?
    I really like the system drawn up by multiball1 (on the yahoo group site) but dont think my current machining expertise is quite up to it yet but has anyone here made this version and if so does it live up to the designers statements?​

    Asian 9x20, some rusty files and a hammer
    ​

  • ​
 
Last edited by a moderator:
Re: 9x20 tool post flex


  • Hi, savarin. I'm totally clueless about your machine, but maybe this can be of some help.

    I recall my dad having similar 'flexing' problems, especially with parting. He made a gooseneck parting holder, but still experienced that chatter. Fast-forward, I'm doing a rebuild/restore on the thing, and discover that the rocker post t-slot plate, concave seat washer, and compound top surface are all warped. Resurfaced them all and a lot of the 'flexing' went away. Now using a 0xa QCTP, with a t-nut cut with a slight 1/2° upsweep on the wings, and that totally fills the slot, and the thicker 10mm fixing stud, and now it's even more solid...​

    --- Steve

    Atlas/Craftsman 6x18 (101.07301) (bushing headstock)​
 
Gunrunner you need to order a set of these for the Z axis hand crank. Bill did you just spit coffee on your monitor? :rofl:

View attachment 253356
 
Last edited by a moderator:
Gunrunner you need to order a set of these for the Z axis hand crank. Bill did you just spit coffee on your monitor? :rofl:

View attachment 253356
 
Last edited by a moderator:
Re: 9x20 tool post flex


  • I like that 'donut' upgrade project, especially his deflection test. May have to give that a try...​

    --- Steve

    Atlas/Craftsman 6x18 (101.07301) (bushing headstock)
    ​

  • ​
 
Last edited by a moderator:
Re: 9x20 tool post flex



Yes Charles, swapping the bolt to a larger one will cure your problem. The original smaller one cannot handle the heavy load put on it by the QCTP. The shims do nothing but take up the space. They do not add to the rigidity. Actually in your case they add to the flexibility of the unit. You are getting much better at your problem solving. The 9X20 is a good teacher.

"Billy G"​

Since others have to tolerate my weaknesses, it is only fair that I tolerate theirs: William Allen White

THE FIRST 5 DAYS AFTER THE WEEKEND ARE THE TOUGHEST.

There are those that see things that are and ask -- "Why"? There are others that see things that have not been and ask -- "Why Not"​
 
Last edited by a moderator:
Re: 9x20 tool post flex


  • The donut mount is worthwhile. Mine was a good improvement but ultimately the compound is the enemy. Makinging a solid platform for the qctp and only using the compound when needed is a better solution on a 9x20. That let me start taking much heavier cuts and part larger diameter steel more successfully.​
 
Last edited by a moderator:
You must log in or register to reply here.
Back
Top