Need Help!- Drawbar gear not the corect size.

[AccuMillGuy]

Hello.

I got up this AM all excited to run my first job on a newly acquired used Enshu AM1547 CNC Mill. To my surprise I was unable to clamp or unclamp my tools properly. The motor was turning and the solenoid was engaging the clutch but my tools were not budging.

After spending several hours stripping things apart I discovered that the gear that is attached to the threaded drawbar, the gear that engages with the clutch attached to the motor, does not seem to be the correct size (it appears the draw bar was not properly threaded into the machine to compensate for this also). I also noticed that the tip of the gears are worn away and it appears that they finally gave up (I was able to use it on dry runs during the week).

Attached are two photos of the gear. I am in desperate need to find the proper replacement gear or make one. If anyone can help me I would greatly appreciate it.

The dimensions of the gear that I have is as follows:

Across flats OD: 1.2810”
ID: 0.5915”
OAL: 0.7080”

From our measurements the proper gear should be the following dimensions:

Across flats OD: 1.3100”
ID: 0.5915”
OAL: 1.8000”

It is possible that the drawbar itself may be the incorrect one. I do not know the history of the machine nor am I able to speak to the previous owner, but the above dimensions should work properly for us.

Thank You

[HuFlungDung]

I would hazard a guess that there is nothing wrong with the part shown. Can you post a picture of the mating part?

The tips of the splines are chamfered on purpose to facilitate engagement of the mating part, which should be a female spline, which is rotated by a motor, but is on some kind of a slide mechanism which pushes the female hub down onto the male spline.

I am not familiar with your machine.

But things to check: make sure that the female hub actuates properly, and moves far enough in travel to engage the spline on the parallel sides of the teeth, not merely bumping along atop the chamfered ends.

Make sure that the ends of the teeth in the female hub are chamfered and not worn round. You may have to regrind the chamfers. It takes two equal and opposing chamfers to make an easy fitting shift mechanism work. Either that, or there may be some sort of delay required on spin-up of the hub so that it is not spinning before it is moved axially into engagement position.

[AccuMillGuy]

We have taken the entire system apart and believe the previous owner took apart the power drawbar during transport and lost the original gear. The spline tips on the gear in the photo are chamfered but also worn down from the other spines, as you put it, bumping along the top of them. It looks like they got a replacement part off another machine and used home made shims + unscrewed the power drawbar to compensate for the length. After a while the power drawbar screws it self back down and does not engage with the motor (explains why we were able to use it for a few days and also explains why the power drew bar was loose when we first disassembled it).

I fabricated a replacement part and all is well now. We have about 15mm of gear engagement.

The teeth on the sliding sleeve driven by the motor and pushed into place by the solenoid are fine and the solenoid pushes them up and down the maximum traveling distance.

Thanks.

Adam