backlash on a new G0619

[negativentropy]

Hello, so I have a new Grizzly G0619 mill, after degreasing, spindle break in and gib adjustment I checked out the backlash on all the axis.

X axis 0.017 in
Y axis 0.010 in
Z axis 0.010 in

Is this reasonable? Can the backlash be reduced in a simple way?

 

[Pitchfire]

It's normal, can be tightened a bit as per ARCEurotrade: http://www.arceurotrade.co.uk/machineguides/Super X3 Mill Dismantling and Reassembly Guide.pdf

Digital readouts will make it less relevant if you go that route.

 

[Richard King]

I see on the Grizzly web site a copy of the manual http://cdn0.grizzly.com/manuals/g0619_m.pdf
and on page 27, it talks about Back-lash. I would think on a new machine more then a .005" would be to much. .002 at that note. It shows how to adjust the feed nut, check that and see if the saddle is the same type. You may want to be a detective and figure out where it's coming from. Check the feed screw end brackets on the table and saddle. The nut holding the handle might be loose. If you have a mag base and a dial indicator mount the mag on the top of the base and put the indicator on the saddle and then stand in front of the machine and with both hands on the table push and pull the table and see if the saddle moves, see if it is the same as the reading you got by turning the dial. It could be several things, The bolts holding the nuts on might be loose, bad feed nuts, the nuts on feed shafts are loose, the spacers under the nuts are to thin, etc. I would think it's a mechanical issue that can be fixed. I would be concerned because if you are climb milling it could cause problems and hole locations will be off. If it's new why not call the factory tech support and see what they tell you.

 

[negativentropy]

Ah thanks guys - somehow I missed that page in the manual, and I had an older version of that guide from arceurotrade. I'll post results after following these instructions.

 

[fretsman]

I have the G0704 and not only were the feed screw nuts both VERY loose, I was actually missing a mounting screw on the Y axis, and the other mounting screw was loose, so there was plenty of "slop" to be fixed up in those areas.

I'm now quite pleased with the machine but they could prep these a little better in shipping/packing. Although, we'd probably pay a lot more for them. In all honesty, I wish they'd ship them un-assembled as I think most of us take them all apart anyway, lol!

Dave

 

[negativentropy]

Hey Dave thats a good point about receiving them dissembled - that way theyd be easier to get onto the bench also...

Anyway, I adjusted the half nuts and got the Y-axis down to 0.001 and X-axis to 0.003. The Z-axis does this weird thing when raising the head; after 0.001 of backlash it first drops about 0.007, then begins raising, so only after about 0.015 are you moving in the direction you want past the original starting point...

Im guessing its best to always approach a desired point by lowering the head?

 

[Richard King]

Hey Dave thats a good point about receiving them dissembled - that way theyd be easier to get onto the bench also...

Anyway, I adjusted the half nuts and got the Y-axis down to 0.001 and X-axis to 0.003. The Z-axis does this weird thing when raising the head; after 0.001 of backlash it first drops about 0.007, then begins raising, so only after about 0.015 are you moving in the direction you want past the original starting point...

Im guessing its best to always approach a desired point by lowering the head?

Oil the Z axis first and then if that doesn't matter loosen the Z-axis gib a little. The head should hang on the nut.

 

[fretsman]

That is strange, it almost sounds like it's hanging at the bearing plate where it meshes with the crank?

Dave

 

[piscesjb]

I also recently purchased a grizzly g0619. I also installed digital read outs on the x and y axis(made by igaging, under $100.00), but how do you measure accurately the backlash. Mine seems to be excessive? I am also in the process of moving the x-axis power feed to the z-axis to eliminate all the head cranking. As part of this process, i have located a very nice x-asis power feed to replace the original power feed. I haven't purchased it yet, as still evaluating and looking, as the price is $800.00. The unit i'm looking at is made by oriental, package #blf6200a-50. You can select your exact speed and this unit delivers 1.6 to 80 ipm(inches per minute). The original power feed (without the ability to control accurately the table feed) was under $300, but one needs to accurately control the feed rate! If anyone has any suggestions on a package that is less expensive, i would greatly apprciate hearing from you. Thanks.