Excessive Backlash Y axis of Standard MIll- Not the screws or nuts, playing with shims but stays at .035"- Ideas?

[twhite]

I figured out that I can use my removed table as a surface plate with the V-Blocks. What do think of the dead blow whack? I'll see what the magntiure of the wowwee is I guess and go from there...

It should be ok if you don’t have a press. You make due which the tools you have.

May I suggest clamping your blocks down to the table. You will want everything as solid as possible. Also clamped down they will not bounce around and mar your table.


Cutting oil is my blood.

 

[jwet]

Thanks very much- my first cursory check without everything fully secured is no discernable bow. Lead screw with acme thread resting across some decent 3" V- blocks, slide underneath indicator to get peak reading, can't see any bow yet. I would think that the bow would have to be 3 or so thousandths over 6" to make it this stiff or similar in rotary runout but maybe its takes less (opinions)? My setup shows about 1 thou with a tenths indicator which is probably the limits of my setup. I'll put some time in hold downs and get out my fancy indicator. I was also thinkinng to get the flange bearing etc mounted on the table somehow to see if it some slant or junk in those bearing journals? Still in the weeds- Thanks again for the support.

 

[twhite]

Thanks very much- my first cursory check without everything fully secured is no discernable bow. Lead screw with acme thread resting across some decent 3" V- blocks, slide underneath indicator to get peak reading, can't see any bow yet. I would think that the bow would have to be 3 or so thousandths over 6" to make it this stiff or similar in rotary runout but maybe its takes less (opinions)? My setup shows about 1 thou with a tenths indicator which is probably the limits of my setup. I'll put some time in hold downs and get out my fancy indicator. I was also thinkinng to get the flange bearing etc mounted on the table somehow to see if it some slant or junk in those bearing journals? Still in the weeds- Thanks again for the support.

That is looking pretty good to me. It is very strange it tightens up in the mid travel. That would indicate to me a bent screw. No real bend. I am at a loss.


Cutting oil is my blood.

 

[jwet]

Tom, thanks a lot for sticking with me on this, helps a ton. Its 1 pm and I'm going to have a beer and get away from this thing- first summer weather here in central Carolina- pretty nice really. I hope the hammock still works- have to dig it out of the shed.

 

[jwet]

Y Axis handle- A possible smoking gun and why its been so hard.. The original owner told me that it got loose from its moorings on a previous move. It slid into something solid, said it was fine. I suspect that the shipper beat the shaft back to square in front of the thrust bearing to keep the dial, etc. from scraping. This then left some wildness though the journal and thrust bearing. I'll revise my setup. Left is handle wonky ness and right is setup so far. The beer and the hour in the hammock worked.

 

[twhite]

Y Axis handle- A possible smoking gun and why its been so hard.. The original owner told me that it got loose from its moorings on a previous move. It slid into something solid, said it was fine. I suspect that the shipper beat the shaft back to square in front of the thrust bearing to keep the dial, etc. from scraping. This then left some wildness though the journal and thrust bearing. I'll revise my setup. Left is handle wonky ness and right is setup so far. The beer and the hour in the hammock worked.

If the threads are straight. Then check the shaft where the handle fits. That might just need a bit more persuasion to get true.

You will find it I am sure.


Cutting oil is my blood.

 

[sdelivery]

Take a closer look at the threads on that screw...

 

[jwet]

This will be the final installment (I hope) of the saga of the Grizzly Wood Mill backlash mystery, thanks especially Tom White for the help. Also, sdelivery, I don't know if you saw something specific but I think you hit it.

The final setup that kind of settled it for me was to mount the Y axis screw on the removed table. I clamped the Y axis outer bearing housing with the lead screw and handle all fitted as in the machine. This was mounted firmly to one end of the table with hold downs with the crank over the edge. I put the big nut cube on the lead screw and put a greased wood spacer block under it to get it on axis and be able to crank in and out. I could then operate the lead screw out of the machine and could see what was going on. The leadscrew is bent just a tiny bit- probably just 2 thousandths. You have your choice of cranking in on the antibacklash nuts to make it very stiff but ok on backlash or adjusting for free running and accepting .030 backlash. The original owner who owned it for 20 noted that the Y axis handle was a bit bent on arrival, this was much worse than thought. The shipper banged it in to "workable"- original owner had no experience and knew no better. The X axis moves like butter with a few thou of backlash, the Y axis runs somewhat smoothly at .03 or very stiff at anything less than 10. My notes from my presale inspection looked at spindle runout, I noted that the Y axis was a bit sloppy but reasoned that this was just adjustment since it had so few hours on it.

Final outcome- Grizzly had a Y axis leadscrew in stock for $205, kind of amazing, this thing hasn't been made for 15 years or more. Its on the way- I make a final final epilogue if its worth talking about.

Thanks to all that helped or spent time reading. This is a great board. Drink Ovaltine.

 

[Flyinfool]

A press is better than a whack, way more controllable.
By the time you have things soft enough to protect not only the whack point but also the support points, most of the force of the whack is absorbed in those 3 soft points. Can you set it up between centers on the lathe to check it for straightness. How you go about straightening it is dependent on if it is a gradual bend over the full length or a localized bend in just one spot. If it is localized bend and you straighten over the full length you will end up with an "S" shaped screw that is very hard to straighten out.

 

[twhite]

This will be the final installment (I hope) of the saga of the Grizzly Wood Mill backlash mystery, thanks especially Tom White for the help. Also, sdelivery, I don't know if you saw something specific but I think you hit it.

The final setup that kind of settled it for me was to mount the Y axis screw on the removed table. I clamped the Y axis outer bearing housing with the lead screw and handle all fitted as in the machine. This was mounted firmly to one end of the table with hold downs with the crank over the edge. I put the big nut cube on the lead screw and put a greased wood spacer block under it to get it on axis and be able to crank in and out. I could then operate the lead screw out of the machine and could see what was going on. The leadscrew is bent just a tiny bit- probably just 2 thousandths. You have your choice of cranking in on the antibacklash nuts to make it very stiff but ok on backlash or adjusting for free running and accepting .030 backlash. The original owner who owned it for 20 noted that the Y axis handle was a bit bent on arrival, this was much worse than thought. The shipper banged it in to "workable"- original owner had no experience and knew no better. The X axis moves like butter with a few thou of backlash, the Y axis runs somewhat smoothly at .03 or very stiff at anything less than 10. My notes from my presale inspection looked at spindle runout, I noted that the Y axis was a bit sloppy but reasoned that this was just adjustment since it had so few hours on it.

Final outcome- Grizzly had a Y axis leadscrew in stock for $205, kind of amazing, this thing hasn't been made for 15 years or more. Its on the way- I make a final final epilogue if its worth talking about.

Thanks to all that helped or spent time reading. This is a great board. Drink Ovaltine.

For $205 You will save yourself a ton of time chasing that bend. There are many that will try and fix it, myself included. As stated in the above post. To be able to do it correctly you would need a press and lots of patience.

Out of curiosity did you pick up a new nut also? Or is the old one good still?

Waiting patiently for how it turns out.


Cutting oil is my blood.