View Full Version : Play in Y truck

05-01-2008, 01:17 PM
I have 2 machines, one the z and y trucks r nice and tight, on the other the y truck has play in the lower left corner, is there any way to tighten it up??

05-01-2008, 03:37 PM
On the Y truck I believe the two upper roller are the cam rollers. You will need a thin 12 mm wrench and a phillips screwdriver to adjust them. If the lower is loose you just need the phillips screwdriver to tighten it up.

I added a drop of Locktite Blue to my roller screws and they haven't loosened up again.

05-01-2008, 03:40 PM
Just remembered! You need to pop off the dust covers to make the top roller adjustments.

05-01-2008, 04:58 PM
the lower screw just keeps turrning........

05-01-2008, 05:15 PM
the lower screw just keeps turrning........
Look at the Parts List - Page # 8. You need the flat wrench to hold the nut.

05-01-2008, 05:18 PM

There is a trick to tightening the roller bearings. One is a center drilled and threaded bearing and the other is a eccentric bearing hole. This lets you put a wrench on the nut of the bearing and rotate it until it is at max tightness or top dead center. By adjusting the 2 eccentric bearings to max tightness to the rod rails it holds great. Loosen both eccentric bearings to the looses position and the whole assembly can be pulled away from the rails.

The center threaded bearing must be tightened from the back of the bearing with a flat slot screwdriver. You might be able to reach the back from the underside of the inside of the machine. With the Z you must remove the unit to tighten the center threaded bearings.

The other Eccentric Bearings for the Y Drive can be seen easily from the top and tightened after removing the dust cap. The Z is the same. See the pictures.

Now here is the "SECRET" to adjusting the bearings.... This will save you $300.00 in shipping and repair for a out of warranty.....

The bearing screws are made from very soft metal. When removing the bearing NEVER try to unscrew the screw. It will STRIP.... I KNOW.... HOLD the screw with a QUALITY #2 Philip's. Using the 12 or 13 mm flat bike wrench turn the nut on the bearing as if you were removing a nut. The first 1/4 turn will back off the pressure on the nut and turn the eccentric away from top dead center. Turn both and you can remove the Y or Z Drive.

When Installing the "Secret" is that you get the eccentric Nut CLOSE to tight, about 1/4 turn from tight holding the screw with that quality #2 Philip's. Then make the last 1/4 turn tightening the nut and at the same time making the eccentric top dead center or at it's closest position to hold the Y or Z Tight. Moving the Axis helps center the bearings on the rails too.

It is either Top Dead Center or it is NOT.... Too loose could cause the head to come OFF during carving. Make that last 1/4 turn tightness PAST an already tight bearing nut but NOT at TOP DEAD CENTER could cause you to SNAP THE SCREW OFF..... It's a game of ALMOST Tight and ALMOST TOP DEAD CENTER..... That is why LHR did not want US playing in this area.... Understanding what is happening here and doing it yourself will go along way to giving you more satisfaction with your machine.

Good Luck.... To remove the Y or Z you must remove the Drive Motors and loosen the belts.... Watch out for WIRES.... Don't pinch any or cut any.

Picture 1 shows the wrench fitting in the nut on the bearing

Picture 2 shows the back side of the Y drive and the nuts on the bearings on top. The ones on the bottom are center tapped the top ones are adjustable.

Picture 3 shows the bearings, note the pivot point... That circuit board is now gone with the new Z Bundle. I had that bearing loosen up and tried to hold the flat slot with a scribe while the Z head was still on and damaged the dust cover. Replaced the bearing.

Picture 4 shows procedure to tighten.

Picture 5 shows a special screw driver for brass barrel nuts used in Electronic Switchboards. Worked well with this. A Flat screwdriver works good too.

Hope this HELPS,


05-01-2008, 06:10 PM
Ok, i tightened up the y axis with the 2 top nuts and thats fixed, but the lower left screw just turns, so if i understand you right, i have to use a flat head from behind the bearing and hold the phillips screw and tighten, or did i already damage it????

05-01-2008, 09:03 PM
I believe you can use a flat screw driver and tighten the bottom bearing.

A 90 degree screwdriver might help.

Good Job by the way....

A look at my Z with that slot nut holding the bearing nut and you see what you are dealing with. Try to hold the philips screw driver and turn the bearing nut.

Good Luck,


05-01-2008, 11:49 PM
thanks Al for all your help.....I used an inspection mirror to see what was going on....as u turn the screw the peice behind has some sort of loctite on it, it all turns together but less than 1/2" to fit a flathead, so I will use my mill to try making a tool (right angle) to fit that confined space....maybe a peice of round stock and cut across to form a flathead.....I' let you know how i make out....your pics and explanation were very helpfull

05-02-2008, 12:10 PM

Thanks for the update.

Good Luck,


05-02-2008, 01:05 PM
Here is a pic of the driver i made...i left the blade rounded to match the contour of the screw, used 3/8" stock

07-22-2008, 09:42 AM
I found it,,i think,,lol