Belt mistery

[JasonB]

On JasonB Said:

Cedric. Look at the early photos where the motor was pulled up tight to the bed. I the photo you are looking at Sonic  slackened it off so it would pivot away from the bed and reduce the slack but it does not take up enough.

Something weird is going on there (obviously!). In the “before” photo the run of belt from the motor to the idler pulley seems close to vertical. Not so much in the “after” pics. Almost as if the motor is further out now. Or the headstock is further in?

I think I’d just buy a shorter belt and be done with it. Or sleeve the  idler pulley.

[Graham MeekParticipant @grahammeek88282]

Hi Sonic,

Have you tried the motor fitted without your sound deadening strips?

Regards

Gray.

[noel shelleyParticipant @noelshelley55608]

IF the mounting studs are long enough then put nuts on first then the mounting bars then the final nut, it will space the motor out and give a secondary adjustment. Noel.

[Sonic EscapeParticipant @sonicescape38234]

I made a video just to show how ineffective is the tensioner in both positions in which it can be mounted. Then at the end I put the belt in a different way, as suggested. It is almost working. But the teeth are rubbing each other. It doesn’t make any sense to try to fix this issue in other way than ordering another belt. A new one is 4 euro. The question was why the belt is no longer tensioned when everything is (presumably) assembled in the same way.

I put a string around both pulleys and the resulting length is 510mm. Without the tensioner touching the string.

 

 

[Phil PParticipant @philp]

There is your 20″ (510mm) that I guessed it would be on an earlier reply.

Phil P

[SillyOldDufferModerator @sillyoldduffer]

Could the belt tensioner be assembled the wrong way round?   If the roller were on the other side, it would allow a wider range of adjustment.   Like this, arc slot under the roller, not above:

I’m not convinced!

Dave

[Sonic EscapeParticipant @sonicescape38234]

But the pin of the roller can not be removed from the plate. I don’t know how to explain, it is assembled like a rivet.

[Nick HughesParticipant @nickhughes97026]

I understand that the motor mounting bracket might look symmetrical, but by now it must be worth a quick check!

Measure from the bench to the motor shaft centre as it is now, then flip the motor over so that the output now faces towards the tailstock end and again measure from the bench to the motor shaft centre (still visible in the end cover), compare the measurements.

It might also be worth measuring from a vertical face to the centre each time as well.

[noel shelleyParticipant @noelshelley55608]

WE TRIED ! Noel.

[peak4Participant @peak4]

Not withstanding the issue regarding belt tension, which can be cured with a new belt; a couple of observations.

I’ve been having a look at as many Emco machines as I can spot to view different types of motors.
Neil’s Machines, amongst others, show photos of the motor ID plates; They appear to point to a frame size/shape of Elin motors Austria “LCY-308” sometimes with a suffix of R01 & S01; all have a conventional foot mount as shown in various photos on this thread, along with the square vented pulley guard.
I wonder if in a previous life, one of more of the feet on Sonic’s motor were broken and the sliding bar arrangement bored through the end plates as an alternative mount, with the angled part machined off.
One hole at each end appears to be sleeved, but it’s hard to tell from the photos. It would be the same hole in each of the castings, but top at one end and bottom the other.
It’s possible that there is a subtle difference in the centring of those pairs of holes with respect to the motor spindle, which isn’t immediately obvious.
As Nick, the previous poster, mentioned, turn the motor over and do comparative measurements using the same mounting studs on the lathe bed. I did suggest this a while ago.

Regarding the originality of the vertical spacer block and the deeper mounting block for the tailstock, Sonic seems to feel that they are original due to the Hammerite style painting.
Again, it’s hard to tell from the photos, but the lathe seems to be painted a blueish/grey Hammerite, whereas the underside of the tailstock and sides of the headstock spacer is a greenish/grey.

It’s more obvious when you look at the later mobile phone photos of the headstock end.
If the changewheels are still in their original factory paint job, it should provide a sample to compare.

Bill

[Sonic EscapeParticipant @sonicescape38234]

No, the motor was designed from the start with that sliding bar mount. Just look at this picture. It looks like a mounting system that allow a wide range of axial adjustment. Useless in this case.

Here is the motor type:

Last night I measured the distance between the motor spindle and a screw hole on the headstock. and then I mounted it in reverse and measured again. It is easy because the spindle is not cover and the bottom end. The results were the same. The motor is perfectly symmetric.

I looked carefully and the two motor covers have a tiny difference that allowed me to figure out after comparing with the original pictures that I reversed them. But it makes no difference.

The color on the bottom of the tailstock is the same like on the rest of the lathe before repainting it. Here is an original change wheel together with the tailstock:

I’m more interested why there is a second cross slide between the carriage and the normal cross slide. I don’t want to use it. Raising the tool post in this way makes no sense!

Interesting thing, before all this belt mess I posted a comment in the “How do I learn machining” thread. Among a few other things I said something like that unlike electronics or programming in mechanics I’ve never come across anything that I couldn’t understand. And not even 24 hours later the belt is too long. I think the god of mechanics is listening to this forum! 🙂

[peak4Participant @peak4]

It gets curiouser and curiouser; The only reason I can think of for a longer cross-slide would be to allow longer pieces to be milled with a cutter in the main spindle.

It must just be a trick of the light and maybe different cameras with varying colour temperatures

This photo made me think that the 75 tooth gear was the same colour as the bed, but the spacer plate looked more green

Bill

[cedric 1Participant @cedric]

Sonic, if you can post some photos of the double cross slide assembled on the lathe, even loosely , we might be able to offer some ideas on its purpose. It is difficult to imagine without seeing it.

[Nick HughesParticipant @nickhughes97026]

O.K, If you have already tried physically flipping the motor around/over, rather than just taking a photo end on and guessing (Didn’t see mention of flipping the motor around/over in the postings),

Then as you have also had the headstock off, I would suggest that this may be out of line, with the pully end twisted too close to the motor and/or bodily pushed too far to the rear (The bolt hole clearance allowing some amount of variation and adjustment).

Surely the motor and headstock positions are the only variables, as the OP is adamant that this is the original belt fitted and correctly adjusted when the lathe was purchased.

[Graham Meek]

On Graham Meek Said:

Hi Sonic,

Have you tried the motor fitted without your sound deadening strips?

Regards

Gray.

I posted the above because I think the introduction of the “Vibration Dampers” or sound deadening strips, are the only thing that has changed. They were not part of the original build set-up.

Contrary to popular belief the Motor needs to move closer to the bed and the adjustment pulley rather than away from it. This will make the pulley more effective. This was pointed out in an earlier post.

Regards

Gray,

 

[Graham Meek]

On Graham Meek Said:

On Graham Meek Said:

Hi Sonic,

Have you tried the motor fitted without your sound deadening strips?

Regards

Gray.

I posted the above because I think the introduction of the “Vibration Dampers” or sound deadening strips, are the only thing that has changed. They were not part of the original build set-up.

Contrary to popular belief the Motor needs to move closer to the bed and the adjustment pulley rather than away from it. This will make the pulley more effective. This was pointed out in an earlier post.

Regards

Gray,

 

Plus one on that. As I posted earlier, it looks like the motor needs moving in closer to the lathe bed so the belt gets more wrap around the idler pulley.

I hadn’t seen any reference to the fitting of vibration  damper strips, but now see them in some pics, between the motor and lathe bed. If they were not there before, they may well be the cause of your problem.

[noel shelleyParticipant @noelshelley55608]

The small size of the motor pulley means that the 2 inner faces of the belt will touch as there is little room for adjustment. The belt must be of a close size to be able to be adjusted with in the limit above. A larger idler pulley will only work so long as the above condition does not occur. A smaller belt seems the only option. Noel.

[Graham MeekParticipant @grahammeek88282]

Post deleted.

Gray.

[JasonBModerator @jasonb]

One of the links I posted earlier shows there was a change in motor at one time. FFD are listed as the later manufacturer.

Thousands of Myfords with the longer top slide so easy to see why one may be fitted as well as milling it allows the fitting of a rear toolpost

I’m kind of wondering if this was a factory machine that fell between the Emcomat/maximat 7 and the compact 8 where they used spacers before using a new casting like I had on my Emcomat 8.6

Paint on mine varied and was infact the hammered early finish under the later green, I suspect a smine was a ex demo machine from the importers that it was just given the latest colour when they changed the factory colour.

[JasonBModerator @jasonb]

[MichaelRParticipant @michaelr]

As you say the lathe was reassembled correctly, have a look at this link it may give a clue to the problem

https://www.google.com/search?q=can+a+toothed+belt+stretch+after+it%27s+removed+from+pullys&rlz=1C1GCEA_en-GBGB1186GB1186&oq=can+a+toothed+belt+stretch+after+it%27s+removed+from+pullys&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCjQyNDYwajBqMTWoAgiwAgE&sourceid=chrome&ie=UTF-8

MichaelR

[MichaelRParticipant @michaelr]

As you say the lathe was reassembled correctly, have a look at this link it may give a clue to

 

https://www.google.com/search?q=can+a+toothed+belt+stretch+after+it%27s+removed+from+pullys&rlz=1C1GCEA_en-GBGB1186GB1186&oq=can+a+toothed+belt+stretch+after+it%27s+removed+from+pullys&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCjQyNDYwajBqMTWoAgiwAgE&sourceid=chrome&ie=UTF-8

[Dave HalfordParticipant @davehalford22513]

According to Lathes.co the wide belt like yours is obsolete, they only have the 19mm size. That implies your belt might be a longer replacement, hence the reversed tensioner.

[peak4Participant @peak4]

Another passing thought on re-assembly, since Sonic is pretty sure all parts are present and correct, regardless of whether they originate from the factory or elsewhere.
From the photos, this hypothesis isn’t obvious to confirm, due to parallax effects etc.

We have all been assuming (I think) that the two horizontal bars should be bolted against the bed of the lathe, as shown in the second screenshot, taken from Sonic’s video.
However, since the bars pivot, unlike rigid feet seen on other motors, how about having the bottom bar bolted to the bed as shown, but with the motor pivoting away from the bed at the top, with the top nut(s) pushing it away from the bed. Effectively the lower bar becomes a hinge.

To my eye, trying to take the perspective into account, the long studs which hold the end caps onto the motor don’t look vertically above one another. That is, the red arrow distance to the rear of the lathe bed looks longer than the blue. Hard to tell when viewed from this angle.

That is, in the photo below, bolt the bottom up fully, and move the top right facing nut with the red arrow, to where the blue arrow points and have the nut facing left.
This would have the effect of moving the motor’s centre, both out and downwards.
I’m not suggesting this as a final good engineering solution, but is this how the lathe arrived from the previous owner?
Sonic could, if this works, replace the top studs with longer ones and then bolt the motor up fully.
I’m not sure if this would push the motor too far down and have it foul the bench.

The green lines above are nominally vertical, and parallel to the read of the bed, but were they when the lathe arrived ??

Bill

 

[JasonBModerator @jasonb]

Peak, in your first photo you are comparing the end of the long hex nut that takes the cover screw with a short standard nut on the lower tie rod. If you take the same point top and bottom there is not such a difference.

 

The spacer plate also projects further back than the bed so your vertical red line is also not right.

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