# Problem with lathe feed shaft.



## Madhattan (Apr 13, 2020)

I'm new, like really new....  I just got my new to me Emco MAXIMAT V13 lathe working last weekend and I made my very first chips yesterday.  I am learning the machine and I am having problems with the FEED SHAFT not turning.  The clutch turns but the shaft doesn't and I am unsure what to do next.  As I understand it the Feed Shaft should always rotate then the motor is running.  Any advice out there?

Thanks!


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## mikey (Apr 13, 2020)

The lever below the two gear contol levers should engage the drive shaft. Turning to the left should allow power feed towards the chuck, in the middle is neutral (where I think you are now) and towards the right will feed towards the tailstock. See pic below:




Try shifting the lever to the left while turning the chuck by hand. Do not shift this under power.


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## ddillman (Apr 13, 2020)

if the clutch is turning but the shaft isn't you may need to adjust the clutch. it should be the 2 Allen screws pointing towards the clutch housing


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## Madhattan (Apr 13, 2020)

Thank you Mikey for the assist.  The Feed Engage lever does have three positions: Left, Neutral and Right.  In the neutral position there appears to be no rotational output of the thread and feed gearbox, as you predicted.  In the left or right position the slipping clutch turns as if it wants to turn the feed shaft but the feed shaft doesn't move.  The clutch is obviously disengaged.  If I remove power and put a wrench on the feed shaft I can feel the clutch attempt to engage the feed shaft every 180 degrees then the clutch slips.

Thanks DDillman, I'll try the adjusting Allen screws right now!


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## Madhattan (Apr 13, 2020)

The two holes on the right face of the Slipping Clutch appear to be holes for a pin-face-spanner rather than adjustment Allen screws if we are talking about the two holes.  It appears as if I could take the clutch assembly apart but that story might have a very bad ending.  I am unsure how I would ever get the balls back into the assembly without losing them.  Advice?

Remove the Threaded Ring
Remove the Screw
Remove the Washer
Remove the Ball Cage
Lose the three Balls

Emco Maximat V13 Service Parts Manual Page 4, Item 12 Threaded Ring.


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## mikey (Apr 13, 2020)

It's probable that the shear pin is broken. It is part #16. This is just an aluminum pin meant to shear under excessive load. Simple to make and replace. Do NOT use anything other than aluminum for this pin.

Do you have the manual and parts breakdown?


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## mikey (Apr 13, 2020)

Found the instructions to remove the pin. You do NOT need to disasssemble the clutch pack.




Try to recover the broken pin and reproduce the length and diameter from aluminum. The soft, hardware store aluminum would be best. This pin is meant to shear under excess load.


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## Madhattan (Apr 13, 2020)

Thanks Mikey I have the manual and parts breakdown.  I obtained them from the Files section of Hobby-Machinist.  Thank you Hobby-Machinist!   I found the shear pin.  In the diagram, it appears to me that the shear pin rotationally mates the Feed Shaft to the Ball Cage. Upon inspection, the shear pin seems intact.  When I rotate the Feed Shaft manually the Ball Cage matches the Feed Shaft movement exactly but clicks ever 180 degrees as the clutch attempts to engage but can't quite do it.  I feel and hear a solid click and I can visually see the clutch washer move left as the balls attempt to seat.  I am afraid I am going to have to take the clutch assembly apart...

I wonder if there are instructions on how to remove the Feedshaft and dissemble the clutch assembly?  I'm looking but no luck so far.


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## mikey (Apr 13, 2020)

Okay, then I wonder if the keyed washer might be broken. You might have to remove the clutch and take it apart. I would try to drive the shear pin out first to make sure it is intact. If so, then you have to remove the drive shaft and pull the clutch apart. Keep us posted.


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## Madhattan (Apr 13, 2020)

Hey I want to really thank you guys for helping me out.  I don't know any machinists, I'm solo.

I'm thinking a spot of grease might be just the thing to keep the three balls in the ball cage when I have to put it back together.


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## Madhattan (Apr 13, 2020)

I just read a post that "... as with customary ball-detent torque limiters, spring strain is balanced through the revolution of a nut, just for this situation the components are separately conformed to the sought tangential power, worth, and a torque figuring is made in light of the quantity of components and their separation from the focal point of the rotational pivot."  -unknown

*Perhaps all I have to do is tighten the Threaded Ring (nut)!  I'll try this first.*


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## Madhattan (Apr 17, 2020)

From the Operations Manual: 

*Setting the Slipping Coupling*
"An adjustable sliding clutch is fitted at the exit of the drive spindle on the right hand side of the gearbox.  This clutch slips when the long or cross stops are reached or if any other obstruction is struck.  The coupling is set at the works.  When fitting a new coupling, the following instructions apply.  With a two pin key Np. 35 carefully turn the screwed plate 90 degrees in a clockwise direction.  By operating the machine, check if the adjustment is enough.  If not, repeat until the correct position is achieved."

*Update:* I tightened the Threaded Ring to the limit.  Now at the lower (85) RPM's the clutch will engage; the feed bar will turn; power-feeds the apron; and power-feeds cross-slide.  At higher (700) RPM's the clutch will not engage at all and just slips.  I put the feed engage lever in neutral and disengaged all power feed at the apron and cross-feed then turned the feed shaft by hand.  This should be very easy to turn and almost free wheeling (in my mind) but I encountered a lot of friction!  I think friction on the feed-shaft is keeping the clutch from engaging.


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## mikey (Apr 17, 2020)

Not so sure about the free wheeling thing. With the lathe in neutral, power off, my feed shaft is locked. I cannot turn it by hand. My power feed works properly so I'm wondering if you need to take the clutch pack apart and examine it. It may be the spring is weak and not engaging. There isn't a whole lot else in there.

The other thing you might consider is contacting Emco USA and asking one of the engineers. It may be that their current lineup of lathes uses the same clutch pack. If so, replacement parts might be available. I have found Emco to be very responsive to email queries.


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## Madhattan (Apr 18, 2020)

UPDATE: This morning my daughter and I dissembled the pillow block for the feed shaft, thread shaft and motor power shaft at the tail end of the lathe. We inspected all the bearings and bushings and discovered that the bushing for the feed shaft was gunky and the gunk was the source of the mysterious friction. We cleaned up the bearings and bushings, re-oiled them and reassembled. No ball bearings missing and no extra parts left over! Now that there isn't the extra friction, backed out the threaded ring nut on the clutch and readjusted the slipping clutch in accordance with the manual. Procedure: Tighten the threaded ring nut 90 degrees, test then repeat until the clutch holds and feels right.

We chucked in a 2 in. x 8 in. cylinder of aluminum stock and made a facing cut with the working power feed and then a long cut. Wow so happy!
*
 Problem fixed! *

Thank you for all your advice!


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## mikey (Apr 18, 2020)

Glad you got that sorted.


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## T Bredehoft (Apr 18, 2020)

Give high praise to your daughter, without her you couldn't do it.


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