Circles no longer round

[JDGJr]

My SB has stopped cutting round circles. They are elongated in the X direction. See attached photo20170901_161101.jpg

I've checked:
. New collet & nut
. new 1/8" bit
. router securely mounted
. cleaned rails and re-lubed the rack
. checked X and Y pinion gears, secure and no wear or missing teeth
. Z axis checked at 90 from X car
. properly cuts squares
. problem is not specific to an area of the table

Thanks for any ideas,
John

[jerry_stanek]

I have had this problem when one of my x drives was unplugged

[Brady Watson]

Bring the keyboard with you....

Set MS to 1 inch per sec.

Use keyboard mode. Lightly lean against the Y0 side of the gantry and move the tool with the arrow keys against you. Does it move you with force? What about the Y48/60 side of the machine? If one side gives out - there's your problem.

Turn OFF the control box and check the wiring at the motor, the connector and all the way back. Visually inspect & check for continuity. If that is good, check the driver. If it's a Gecko, you might have to remove the screw terminals that hold the drive to the board, remove the drive, put it back on to reseat the connections. They sometimes get corroded.

-B

[JDGJr]

Thanks you guys.

Forgot to mention that if I use a marker to draw shapes, the circles come out perfect, so it must be related to the torque of cutting material.

Brady: The X (2) and Y motors push against a gentle lean in all directions.

I loosened and reattached the 3 motors using a clamp to hold against the rack, and the circles got a bit better.

One thing I noticed after Brady's lean test - with the power on, if I push against one side of the car (a bit more than a lean, but not a harsh push) it'll move about .25" with the other side not moving. Then the other side will do the same thing, but I can't push the same side twice in a row.

Hope this makes sense to someone. thanks in advance!

John

[jerry_stanek]

Did you drop the 2 X motors and see if they both spin

[JDGJr]

I did, and they do.

[srwtlc]

If this is a PRS...

DO NOT clamp the motors into the rack. Only firm hand pressure upward is required. If too tight, you'll notice a sort of rumble or growl as you jog the carriage in X and it will translate to the cut as well as cause premature wear to the pinions.

If you pull back and forth in the X direction on the bottom of the Z axis, do you get play at the lower Y car rollers? If so, adjust according to the manual and try again.

[rb99]

Gears are loose on the motor shaft. (?)

[JDGJr]

Gears are loose on the motor shaft. (?)

All the set screws on the 3 gears were tight enough I could not tighten further.

[JDGJr]

If this is a PRS...

DO NOT clamp the motors into the rack. Only firm hand pressure upward is required. If too tight, you'll notice a sort of rumble or growl as you jog the carriage in X and it will translate to the cut as well as cause premature wear to the pinions.

If you pull back and forth in the X direction on the bottom of the Z axis, do you get play at the lower Y car rollers? If so, adjust according to the manual and try again.

I've unmounted the X motors and will use hand pressure the next time I install. thanks.

I'll review the manual tomorrow and locate the section that discusses the adjustment you mention.