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Pro tool head OHAI
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Hi guys,
I have another adjustment that we need to make to the OHAI for the Taz Pro tool head. Yesterday (6-24-19) we discovered that it is better off if we stop torquing a few screw. On step 4 it tells you to torque the set screws (HD-BT0162) and we found that if we torque those set screws is causes the assembly to slant at an angle. Also on step 5 it tells you to torque the two (HD-BT0041) screws that help hold the actuators in place. We found out that when we torque them it causes the top rod mount piece (PP-MP0228) to give a little and it makes the top of the smooth rods to move closer to each other. That will cause binding in the motor mounts. So we need to get the torque spec removed for those screws.

-Michael M.

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MichaelM triaged this task as Normal priority.

I can also fill out a change order if i need to

DaniAO added a comment.Jul 2 2019, 9:12 AM

@MichaelM since we are updating the TAZ Pro tool head.. lets see if we can get it in with a current change order

I know @MikeR had some questions for you about that OHAI anyway.

MikeR added subscribers: west, tutley.Jul 3 2019, 1:12 PM

@MichaelM I am hesitant to remove a torque spec without having a good alternative. This would just make it an arbitrary tightness. 2in*lbs is the lowest we can go. @tutley @west can I get your input on this issue?

tutley added a comment.Jul 3 2019, 1:51 PM

I think 2 in*lbs is okay for these fasteners (as well as the HD-BT0041 in step 5)
the problem is that if these are over tightened it changes the spacing of the rods in a way that will cause the motor mount carriage to bind.

we have some in*lbs torque drivers and some in*oz torque drivers. if it is determined that 2 in*lbs is still causing some binding, i would suggest we go to 1 in*lb (16 in*oz) with a small dab of loctite 425

MikeR added a comment.Jul 3 2019, 2:06 PM

@tutley will the cad drawing show the desired distance so I can try the 1in*lb value and check for deflection. Is there an allowed amount of deflection before we start getting carriage binding?

logan added a comment.Jul 3 2019, 2:26 PM

@tutley @MikeR Unfortunately our in*oz torque wrenches (CDI 61SM) only ranges from 20 to 100 in*oz. So 1.25in*lbs is the lowest we can reliably go with these drivers.

Since those fasteners aren't on a plastic part, we could use Loctite 222MS low strength. Or the Loctite 220 Medium Strength used on pulleys/couplers at calibration. I would recommend the medium strength due to increased heat/vibration at the tool head.

logan added a comment.Jul 3 2019, 2:34 PM

@MikeR Here are some target dimensions for you:

Because these dimensions have a tolerance, you will of course need to measure the raw part before torque is applied.

tutley added a comment.Jul 3 2019, 2:36 PM

@MikeR the rod spacing from the inside edges of the rods should be 17.5mm +/-0.075