# Back gear locked up



## metalmole (Jul 6, 2013)

The other day while I was backing out a 1/4 tap in back gear my mill locked up. My mill is an Enco  its not an exact BP clone but I know you guys in this forum have more experience with the inner workings of mills than on other forums...My mill has the one lever on the left side of the head that both lifts the spindle collar and shifts the back gear, Enco doesn't sell the step pulley 10x54 anymore ( that's what I have ) but here is a Grizzly that is the same machine http://www.grizzly.com/products/G9904/images/3
I messed around and got it out of back gear and it runs fine in high speed........any thoughts


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## Richard King (Jul 6, 2013)

I just spent an hour looking at Grizzly and Enco manuals and didn't see that type.  Can you call Enco on Monday and get a maintenance manual for the machine or as to speak with the senior service tech and he might recall any problems on those types of heads.  I used to rebuild Bridgeport heads and sometimes we would loosen the nuts that held the halves together a 1/2 turn and then try to engage the handles to re-align them.  Then if that helped we tightened them back up.    Rich


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## Hawkeye (Jul 6, 2013)

I'm not familiar with gearhead mills, but I'll ask a question or two. Whwn you say that the lever lifts the spindle collar and engages the back gear, am I correct in assuming that the collar locks the spindle to the shaft when the back gear is dis-engaged? (Similar to the pin on a lathe spindle?) If so, is it possible that there is some kind of adjustment that may have slipped, allowing both to be engaged at the same time?

Check out the linkages from the lever and see if something came loose and needs to be adjusted so that the spindle collar is unlocked when the back gear is locked.


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## metalmole (Jul 6, 2013)

Richard King said:


> I just spent an hour looking at Grizzly and Enco manuals and didn't see that type.  Can you call Enco on Monday and get a maintenance manual for the machine or as to speak with the senior service tech and he might recall any problems on those types of heads.  I used to rebuild Bridgeport heads and sometimes we would loosen the nuts that held the halves together a 1/2 turn and then try to engage the handles to re-align them.  Then if that helped we tightened them back up.    Rich





Richard, thanks for looking at the Grizzly site and helping me out, here are some things I have found...Grizzly model # G9904 is identical to mine, but they don’t have a user or parts manual listed on there site. However there G9902 has the same head its just a single speed motor and not 2 speed. Here is the user/parts manual for that head http://cdn0.grizzly.com/manuals/g9903_m.pdf . Page 11 figure 3 shows the speed change lever that puts it in back gear. Page 36 fig 28 also shows the handle. Page 58 fig 83 shows the spindle speed change pin and lever layout, that pin is just like on a BP only on the BP its lifted by the cam ring slot. and page 71 has the parts break down....Im sure that as these machines age there will be others with some problems, mine was manufactured in 2000 and has been a great machine .......

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t t





Hawkeye said:


> I'm not familiar with gearhead mills, but I'll ask a question or two. Whwn you say that the lever lifts the spindle collar and engages the back gear, am I correct in assuming that the collar locks the spindle to the shaft when the back gear is dis-engaged? (Similar to the pin on a lathe spindle?) If so, is it possible that there is some kind of adjustment that may have slipped, allowing both to be engaged at the same time?
> 
> Check out the linkages from the lever and see if something came loose and needs to be adjusted so that the spindle collar is unlocked when the back gear is locked.



Yea Mike sometimes the back gear and direct drive can be engaged at the same time, but careful inspection shows that's not the case. My mills not a gear head, its BP copy only difference is the way you put it in back gear, the back gear works the same, its you just need to move one lever instead of two levers like on a BP...


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## Richard King (Jul 6, 2013)

The book looks like one of the better import manual I have seen. I would say stop trying to guess at whats wrong and pull it part and figure it out.  One can over think some of these repairs sometime.  Or as I said before call Grizzly or Enco / MSC and see if a service tech will help you.
Rich


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