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First post - Help with 1970s Emco Maximat Standard spindle pulley

Joined
Oct 9, 2021
Hi all. Quick intro - I’m into customising vintage Vespas. Have done most work by hand until recently. Picked up a 1970s Emco bench lathe (as per the title). Had been used to turn wood by the guy I got it from.

Cleaned it up, re-greased as per the manual (finding something equivalent to the “ESSO Nebula EP No. 1 the manual specified was tricky), and have been slowly learning how to turn stuff.

Made a chuck key for a drill press (have a dividing head). Replaced the motor with and equivalent 0.5hp but 4 instead of single pole motor (same rpm). Made a back plate adaptor so I could mount an old 4-jaw the lathe came with. Fixed the old motor pulley with loose ID that was wobbling.

Main project I got the lathe for is to modify a flywheel. Trying to mount a starter ring gear (so I can electric start my 1964 custom Vespa).

I’ve been chasing a vibration that does seem a little intermittent. Unfortunately seems to be there more often than not. Was the reason I trued the motor pulley. Seemed to run smoothly straight after I had done that. But as soon as I turn something the vibration comes back, and then doesn’t seem to go away even when there is no load.

I can centre a piece, turn a radius, and everything is concentric. The backplate I made seems to work really well with the chuck centered (although it’s a 4 jaw so would get away with it).

The vibration seems to be like the work the motor is doing is oscillating - I think it may be rotational. The idler arm and even motor itself bounce up and down. I can’t feel any play/knocking or x/y/z movement in the chuck - the spindle bearing themselves sound and feel good.

There is some rotational play (backlash?) between the spindle pulley and the spindle itself. The manual states the pulley is mounted independently “to take care of belt thrust”. Unsure if this play is normal, and if not how to remove the spindle pulley to address it. Any help much appreciated.

Here is the lathe after I had replaced the motor and trued the motor pulley. Seems to be running ok.

https://youtu.be/guXHItLMI4U

Here is a video of me starting to rough cut the fins off a flywheel - but you can hear the vibration/oscillation.

https://youtu.be/4-IfjRobG_g

And here is the play I am seeing.

https://youtu.be/9ha4JcCK-r8
 

Tom A

Cast Iron
Joined
Apr 26, 2009
Location
NW Florida
No experience with that particular lathe, but between the broken small sheave, and the pulley being loose on the shaft, it's no wonder you have vibration. You should at least check to see if there's a loose set screw, or a worn key under that pulley - That kind of movement is not right.
 
Joined
Oct 9, 2021
Thanks for the prompt answer. My guess is there is a key under the pulley? And the keyway or key are knackered. Just not sure how to remove the pulley and don’t want to attempt it blind as likely to damage the pulley (more than it already is!)

The broken sheave is just to the lead screw pulley - no change taking that belt off.
 

Terry Keeley

Stainless
Joined
Oct 18, 2005
Location
Toronto, Canada eh!
Not sure if it's just the video but the noise goes away when you put a load on the spindle, I'd guess your spindle pre-load is loose or the bearings themselves are pooched. Do you have a manual? There should be instructions on how to tighten the pre-load, IIRC for my Super 11 you spin the spindle by hand and tighten the nut until it rotates a 1/4 turn more or something.

Yup, something's probably loose on that pully, is there a set screw or something?

You should use a regular right hand cutter to trim that flywheel, that tool is for parting and is meant to run straight into stock.

Don't be offended if your thread gets locked, check the sticky's at the top. Good news tho, there's a great .io group for these machines, you should ask there:

https://groups.io/g/emcoV10lathe/files

edit: a quick search of the files section:

https://groups.io/g/emcoV10lathe/files/Maximat sparepartslist.pdf

https://groups.io/g/emcoV10lathe/files/Maximat Manual English2.pdf
 

CITIZEN F16

Titanium
Joined
May 2, 2021
Get yourself a proper insert turning tool. Using the side of what looks like a parting blade to turn is very inefficient and even dangerous.
 
Joined
Oct 9, 2021
Thanks heaps. Yeah - I know it’s a parting tool, I did run it straight into the face and got away with it because it was intermittent cutting the fins. I made the fins look like a comb and then knocked the ‘teeth’ off. Was a quick way to remove the material without cutting it all. I could also use the lead screw to cut - facing cuts mean I have to use the cross slide and compound (manually). And sharpening a blunted parting tool is quick and easy. It’s all carbide insert tools now (left hand, facing). Sorry to expose you all to that rough roughing vid - was the only recent one I had that the vibration was obvious in.

Thanks for the links - I’ll dig through them. The V10 is different, but hopefully not completely. No obvious way to remove the pulley stack, nothing on the spindle to tighten. The manual doesn’t have anything about preload. Pretty light content-wise in general. States that if you need to sort the spindle or bearings “it requires special tools and techniques - contact the distributor”.
 

Terry Keeley

Stainless
Joined
Oct 18, 2005
Location
Toronto, Canada eh!
Thanks heaps. Yeah - I know it’s a parting tool, I did run it straight into the face and got away with it because it was intermittent cutting the fins. I made the fins look like a comb and then knocked the ‘teeth’ off. Was a quick way to remove the material without cutting it all. I could also use the lead screw to cut - facing cuts mean I have to use the cross slide and compound (manually). And sharpening a blunted parting tool is quick and easy. It’s all carbide insert tools now (left hand, facing). Sorry to expose you all to that rough roughing vid - was the only recent one I had that the vibration was obvious in.

Thanks for the links - I’ll dig through them. The V10 is different, but hopefully not completely. No obvious way to remove the pulley stack, nothing on the spindle to tighten. The manual doesn’t have anything about preload. Pretty light content-wise in general. States that if you need to sort the spindle or bearings “it requires special tools and techniques - contact the distributor”.


That forum is for anything V10 and smaller, there's a separate one for the S11 but lot's of us post there too.

Guys there will know how to adjust the bearings but as stated they might be pooched.
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
Not uncommon for someone to piggyback a set screw, one on top of the other.
best to pull a set screw all the way out and check the hole for another screw.

If the machine seems smooth just running, and not smooth then your setup may be in error.

Running a big part too fast can cause problems,

DITO on this[Using the side of what looks like a parting blade to turn is very inefficient and even dangerous.
just looked at youtube ..and yes that is not the right kind of turning tool.

But it looks like the movement is not on the key..looks like a bushing of sorts in the pulley.

Should figure that out as it is likely to wear and get sloppy.
 
Joined
Oct 9, 2021
Thanks all for your help. Have joined the emco .io and those documents are really helpful. Sorry - didn't realise the forum was for pro machinists. I understand why - so thanks for pointing me in the right direction anyway. FWIW... here is my custom Vespa =)

IMG_7045.jpg
 

Terry Keeley

Stainless
Joined
Oct 18, 2005
Location
Toronto, Canada eh!
Thanks all for your help. Have joined the emco .io and those documents are really helpful. Sorry - didn't realise the forum was for pro machinists. I understand why - so thanks for pointing me in the right direction anyway. FWIW... here is my custom Vespa =)

View attachment 331770


So yur a Mod then?

6cbd786f566658e1c01f80ef4109ee10.jpg
 

PeteM

Diamond
Joined
Jan 15, 2002
Location
West Coast, USA
Get yourself a proper insert turning tool. Using the side of what looks like a parting blade to turn is very inefficient and even dangerous.

To add, the parting tool is quite likely to end up with some sort of harmonic vibration with that much overhang and what amounts to an intermittant side load (particularly with all those facing cuts shown later).
 
Joined
Oct 9, 2021
So what is the rest of the story? shaving the flywheel to fir another engine into the scooter?

Has a motor transplant - 2005 200cc Vespa motor. Those come with electric starters - the starter ring gear is mounted on the flywheel edge by a very small tapered lip. But I upgraded the ignition system with a variable timing high output DC Ducati system. The flywheel on those has no mount for a starter ring gear. I'm transplanting the original mount to the new flywheel. Similar approach to making a backplate adaptor - will centre it with spigots.
 
Joined
Oct 9, 2021
To add, the parting tool is quite likely to end up with some sort of harmonic vibration with that much overhang and what amounts to an intermittant side load (particularly with all those facing cuts shown later).

Needed the overhang to reach deep enough. Decided to keep the compound over the ways rather than too far off to a side so the tool would take the beating rather than my ways.

It worked, nothing broke, no one died, material was removed (and very quickly). No point speculating what might happen when it's already done (and it didn't happen).

If I had a nice big grunty industrial lathe then I for sure would've turned or faced may way in - but with a 0.5hp bench lathe I did what I had to.
 
Joined
Oct 9, 2021
Lastly - I managed to get the spindle pulley stack off. Someone had bodged the keys connecting the pulley to the spindle with homemade brass keys. They were worn. Managed to refit them and almost no play now. It's running much better - the oscillation has gone. Thanks for your help everyone.
 








 
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