Belt mistery

[Wade BeattyParticipant @wadebeatty78296]

On the photo on the right it looks like there are 2 spacer plates between the base and the headstock, on the right only one

[duncan webster 1Participant @duncanwebster1]

If the headstock is too low it will be obviously not in line with the tailstock, easy check

[blowlamp]

On blowlamp Said:

The motor mounting looks a bit odd because of the gap between the bars and the bed, which means that the bolts don’t have the correct clamping effect. Are you sure that spacers or bracket of some sort aren’t supposed to fit between the motor and the bed?

…

Martin.

I agree with Martin – a spacer plate is missing.  There’s one in this picture:

The headstock studs clamp through slots in the spacer plate, not those rods. I guess the plate is tongued to slide in the slot cut in the side of the headstock.

Evidence something is missing.  As pictured:

• The belt is far too slack and there’s no obvious way of adjusting it with the studs and rods.
• The rods don’t fit the holes in the motor
• The motor clamps directly into the bed with no adjustment, which is unusual
• Motor mounts usually provide the missing features, ways of:
  • clamping the motor firmly in right / left alignment with the headstock pulley.
  • adjusting the motor in / out.  Might be done by the thickness of the plate alone, but…

I suspect a missing spacer-plate pushes the motor further away from the bed and drops it below the studs, the extra distances adding up enough to adjust the belt tight.  Having the tensioner roller the right way round might bring the adjustment into range too.

It’s all very odd.  Is it possible the lathe is a “bitsa”, that is a good one put together from parts scavenged from two or more damaged machines?  If so, maybe the rebuilder didn’t have the correct spacer-plate and did his best with what he had?  Or, if Sonic is like me, the missing part is in the fridge!

🙂

Dave

[JasonBModerator @jasonb]

Dave, that picture is for a motor with a more traditional foot so no missing spacer. You can see this type of motor mount in all the online manuals that I have found.

It is also the same type of mount that the 8.6 that I used to drive had.

 

[JasonBModerator @jasonb]

Also if you blow Sonics first photo up of the before and after you can see the same bar mounts and no “plate” on the right hand image where the belt is tight.

[peak4Participant @peak4]

I’ve had a lack of inspiration to head for the workshop, as it’s freezing out there, but I do like a mystery.
Extensive picture searches fail to find any Emco 7 with that extra (now red) spacer plate under the headstock.
Similarly, none of the pictures I can find show such a deep mounting block under the top tailstock casting.
There might be a pointer in Sonic’s last post on the previous thread about an extra slide on the carriage.

A new lathe

e.g. https://www.nielsmachines.com/en/emco-emcomat-7-spare-parts-tailstock.html

See also

The bed itself does seem to have alignment screws, but not the additional red plate.

I’m suggesting that all bets are off when comparing it to existing models seen elsewhere.
Why two cross slides?
It looks very much like the lathe has been modified for a slightly greater centre height, with the addition of the red plate; How does the measured centre height of this lathe compare to the published capacity?
The original paint colour did seem to match, but maybe it was re-painted after modification, as it seems odd that the factory would add a second cross slide, even for a special order.

Bill

[peak4Participant @peak4]

p.s. to the above, if you look on Neil’s Machines, it looks like those headstock adjusting screws, through the lathe bed, press on the studs themselves, rather than on a tenon in between the lathe shears.
https://www.nielsmachines.com/en/emco-emcomat-7-spare-parts-headstock.html

Screenshot from the video in previous post

Bill

[Sonic EscapeParticipant @sonicescape38234]

I usually remain with extra parts after I reassemble things, but I’m sure the motor used no spacers. Also my type is using a different mounting system, not like the more conventional one from the manual. Here it is:

I looks like a system that allow greater axial adjustment range. Also you can see the 4 M5 screws on the yellow bed on the right. I didn’t removed them. And their length is enough only to allow to mount the motor without any spacers. I could barely fit some soft material between the motor an the bed.

Thanks to Bill I realized now that the red riser block I have is not standard! It is missing in all other Emcomat 7 pictures, like bellow:

So in my case the headstock doesn’t stand directly on the bed:

But that red block was not added by the previous owner, because on the other side it has the original green color:

So this is an original part.

If I might deviate a little, this partially explains why the lathe has two cross slides. But it also makes no sense. The second slide will eat away the space you gain by rising the headstock.

Also I have a doubt that the second slide is original. Because look at this detail:

The hole on the left slide is made a little to the left. Like somebody did a sloppy work with a hand drill. Also there is no reason for it. And also the extra slide looks to me like a different quality. On the back it has those zig-zag groove to retain oil. Emcomat doesn’t have that feature anywhere else on other slides.

The tailstock is matching the height of the headstock + red riser block. Another indication that the red block is original. Here is the approximative height of this lathe:

 

[Engine BuilderParticipant @enginebuilder]

I think the roller is mounted on the wrong side of the adjusting plate. Could it be it was reassembled wrong?

If it is removed and refitted on the other side of the plate it will affect the height of the roller.

[Sonic EscapeParticipant @sonicescape38234]

Here are some high resolution pictures I found on my phone. I can clearly see at least 15mm between the bottom of the motor and the stand. Not the belt is tensioned only is the motor sits on the stand. Regardless of the tensioning roller position.

I don’t have a similar belt at home to mix them by mistake. I even counted in the picture how many teeth the bels has. And it is matching with the one I’m using. It beats me how is this possible.

[peak4Participant @peak4]

“The tailstock is matching the height of the headstock + red riser block. Another indication that the red block is original. Here is the approximative height of this lathe:”

Yes, the centre height of the tailstock is correct, but the base part of the tailstock is also thicker than any photos I’ve seen, so was likely specially made to match the headstock.
Does that look like an original part, or may it have been made later?
Paint wise, were the lathes originally supplied with a pot of touch up paint, or maybe a previous owner bought a tin from Emco.

None of this of course helps with why the belt doesn’t fit/tension, but is certainly a curiosity as to whether this is all out of the factory, or a later addition.
The extra cross slide seems a little strange too.

Bill

[Engine Builder]

On Engine Builder Said:

I think the roller is mounted on the wrong side of the adjusting plate. Could it be it was reassembled wrong?

If it is removed and refitted on the other side of the plate it will affect the height of the roller.

I didn’t disassembled the roller from the plate. It is not even possible to do it without destroying it.

[peak4]

On peak4 Said:

“The tailstock is matching the height of the headstock + red riser block. Another indication that the red block is original. Here is the approximative height of this lathe:”

Yes, the centre height of the tailstock is correct, but the base part of the tailstock is also thicker than any photos I’ve seen, so was likely specially made to match the headstock.
Does that look like an original part, or may it have been made later?
Paint wise, were the lathes originally supplied with a pot of touch up paint, or maybe a previous owner bought a tin from Emco.

None of this of course helps with why the belt doesn’t fit/tension, but is certainly a curiosity as to whether this is all out of the factory, or a later addition.
The extra cross slide seems a little strange too.

Bill

I believe that he extra thick base of the tailstock is original. Who would bother to paint it in the original green color on it’s bottom side.

But the second cross slide is strange indeed. Doesn’t make sense. Is just extra work. You could simply rise the tool post!

 

[Sonic EscapeParticipant @sonicescape38234]

Speaking of misteries. Now I noticed that the cross slide on the Emcomat 7 is the same length as the carriage.

But on my lathe it is significantly longer! I mean it is so long that it will hit the milling attachment column! Strange

Not that is has anything to do with the belt but is something seriously wrong with this lathe.

[WaggonermanParticipant @waggonerman]

As both the Motor Bars swivel with what looks like some clearance in the Motor frame eyes, then if the upper Motor Bar had jacking Nuts on the Bed side of the studs this would skew the Motor / Pulley downward tightening the Belt, looks like the visible upper Stud has a Locknut right at the end of the thread in the ‘before’ photo.

Just an observation.

[peak4Participant @peak4]

“But on my lathe it is significantly longer! I mean it is so long that it will hit the milling attachment column”

But if you don’t have the milling attachment it wouldn’t be a problem; that may be the reason, so that longer workpieces can be milled.
Use an angle plate on the  extended topslide, with a milling or flycutter in the headstock spindle.
Lots of people fitted the longer Myford Super 7 topslide to their short slide ML7 lathes for a similar reason.
It might explain why two topslides.

Maybe not “wrong”, just adapted for a purpose.

Bill

[JasonB]

On JasonB Said:

Dave, that picture is for a motor with a more traditional foot so no missing spacer. You can see this type of motor mount in all the online manuals that I have found.

It is also the same type of mount that the 8.6 that I used to drive had.

 

Ahh, no prize for me then!

How can this puzzle be so difficult?  Should be obvious, because the belt is far too long: something biggish is out of place or missing.

Top marks to Sonics for taking photos, but they don’t quite show how the motor was originally attached.  Frustrating.

I can’t think of an explanation other than a missing spacer. Something hidden that moves the motor further away and needs that long belt.  But that idea doesn’t fit with this photo:

I’m on the wrong track!

Very educational this forum: I’d no idea that this lathe had so many variants and clones.

Dave

 

[blowlampParticipant @blowlamp]

I’m finding it difficult to believe that Emco would have mounted the motor in that way.

I’ve never seen an arrangement like that before.

You’ve got cross-drilled round bars which are unsupported under the holes, along with the weird way the motor to bed contact area is unmachined where it meets the bed. It seems like very sloppy engineering, which I wouldn’t expect from Emco.

I know it doesn’t explain how it was apparently functional before, but it just doesn’t feel right to me.

 

Martin.

 

[cedric 1Participant @cedric]

Looks like it needs some spacers or thick washers between those two round bars and the lathe bed. You have about 8mm of thread sticking out on the mounting studs. Try packing each one out with a stack of washers.

[Sonic Escape]

 

On Sonic Escape Said:

Here are some high resolution pictures I found on my phone. I can clearly see at least 15mm between the bottom of the motor and the stand. Not the belt is tensioned only is the motor sits on the stand. Regardless of the tensioning roller position.

I don’t have a similar belt at home to mix them by mistake. I even counted in the picture how many teeth the bels has. And it is matching with the one I’m using. It beats me how is this possible.

Well there is the answer then. Has it been staring us in the face?

Leave the motor where it is (or was) and rotate the black plate carrying the idler by 180 degrees. Not only will the arc of adjustment make more sense but the idler position will take up more of the belt length.

Still seems odd that Emco did not put the idler on the slack side of the belt run.

Ian P

[larry phelan 1Participant @larryphelan1]

Since you say you have only one belt and if that is the original, it would seem that you have rebuilt the machine wrong, so there would be no point in buying a different belt.

Just saying !

Why not take it apart again and CHECK every part to see how they all fit, because SOMETHING is not right there.

Someone once said that it pays to take a few pictures when doing things like that, could save a lot of grief.

Sorry I cannot help more, but NOTHING like that has ever happened to me [or if it did, I choose to forget it ]  Fact is, been there,done that ,even had a few bits left over !

[Nigel Graham 2Participant @nigelgraham2]

I think this thread is sprawling from the original Belt Mystery – next instalment will examine the tailstock!

Going right back to the original photoes, and looking at some of the replies, it seems to me Sonic has not changed any components, just slipped up somewhere in re-assembing it, so does not need worry about relacement belts and raising blocks.

I thought the pad might not affect things but to be sure, I would:

1) Take that anti-vibration pad out – go back to as-was.

2) Put the motor on the studs, lightly tighten the nuts so the motor contacts the bed.

3) The tensioner: Repainting has lost any obvious witness marks there may have been in the original paint, but if the new paint is simply over the original there might be very slight ridges just detectable by finger-touch or different lighting angles. Worth looking to help verify the tensioner’s orientation.

It seems on this lathe, the tensioner swings on the right-hand screw, and is clamped by the left-hand screw in the slot. The first photo shows still some adjustment possible. So refit it that way round.

The diagrams showing opposite-hand orientation may be for other versions of the lathe. I suppose a former owner might have fitted an over-length belt, but since no parts have been changed here it should still go back together as it was!

4) Slip the belt back on the pulleys and establish if it will now tension properly.

5) If it still needs more even with the adjuster at full slot-end, try adjusting the motor retaining nuts, without taking them beyond flush ends.

If this combination of moves looks hopeful, were there any spacers, perhaps just large-diameter washers, on the studs to help place the motor as it needs?

 

As for the resilient pad, I can see its aim but I am not sure if it is a good idea. It might not be very effective but worse, might distort under the belt pull, and put the motor and driven shaft out of parallel.

[larry phelan 1]

On larry phelan 1 Said:

Since you say you have only one belt and if that is the original, it would seem that you have rebuilt the machine wrong, so there would be no point in buying a different belt.

Just saying !

Why not take it apart again and CHECK every part to see how they all fit, because SOMETHING is not right there.

Someone once said that it pays to take a few pictures when doing things like that, could save a lot of grief.

Sorry I cannot help more, but NOTHING like that has ever happened to me [or if it did, I choose to forget it ]  Fact is, been there,done that ,even had a few bits left over !

I echo this sentiment, if the belt is the same one you have re-assembled the lathe in a different way.

Tony

[Ian P]

On Ian P Said:

Still seems odd that Emco did not put the idler on the slack side of the belt run.

Ian P

I thought that too at first, but then looked again – as the spindle drive is via a gearbox, is that actually the slack side, with the motor running anti-clockwise?

Rob

[Phil PParticipant @philp]

Sonic
Can you tell us what the numbers are marked on the belt ?

According to the parts list it should be a 190 XL 075
With details on this link, does it actually have 95 teeth ?

https://www.tyma.eu/products/190-xl-075-conti-synchrobelt-neoprene/?srsltid=AfmBOoqo5EAvD95hTaxqt_kbJLVbKXUW0VH4lwzqnBOKFbUNNpmiOOP2

[Author]

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