No timing belt available for lathe

[rusel]

Need help, suggestion, advice
I can not locate a timing belt for my CQ6125 bench lathe (China made *$@^)
Been to two different belt retailers and they can not identify the belt. Pitch is about 4.8mm, 18mm wide and 2.2mm thick with 118 teeth
The place where I brought the lathe (Hare & Forbes) told me to replace the pulleys with standed pulleys as there do not stock spares #$*@&.

First problem with this is the large timing pulley and the 3 vee pulley cone are all one part
Any one be here before?
Any suggestion

Russell

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[RICHARD ZASTROW]

.48 mm pitch???????

Dick Z

[rusel]

Meant 4.8mm pitch

[Al_The_Man]

Could it be 5mm pitch?
Misumi have a 5mm pitch in either 15mm or 20mm wide 118t.
Type T5 (TTBU).
Their part no is 590T5 if it is close enough.
Al.

[rusel]

Al thank for the reply
Tried a 5mm pitch belt on the pulley and it start to rides over the teeth after 2-3 teeth.
It is less then 5mm pitch.

Here is photo of large pulley as you see it is one part with vee pulley
Russell

[Al_The_Man]

It looks the same as fitted to the R.O.C. lathes imported by Lathemaster in the US.
Although the large timing pulley is 18mm wide the belt is 15mm. 118t.
I converted a 9" x 30" for my son so I have the pulleys and belt as we fitted a direct drive spindle motor.
The belt is translucent with reinforcing fibres visible.
http://www.lathemaster.com/
I checked the one we have it is 124t, but probably the same make/origin
Al.

[mikej65]

If you can get me the sprocket OD and tooth count, I should be able to tell you what you need.

Mike

[rusel]

Mike
Large pulley
OD 134mm
ID 25mm
Width 18.5
90 teeth

Small pulley
OD 27.65mm
ID 16mm or shaft is 15.75mm
Keyway 5mm wide 3mm high
Width 18.5
19 teeth

Centres are 155mm with some adjustment available

Russell

[rusel]

Thank Al
I was talking to my son about direct drive spindle motor as well, have be toying with the idea for a while now.The question is put the money to it or the new pulleys?
Also looking a cnc the lathe already got glass scale on it only need the servo motors, ball screws, mounts and the list goes on on.......
Russell

[RomanLini]

My guess is a 3/16" pitch belt of 3/4 width as the pitch 4.8 is almost exactly 3/16", and your 18mm width is a little less than 3/4" but they often wear a bit on the edges (or skimp on width!).

You could try a USA online supplier like McMasterCarr or if you want to stay in Sydney then most industrial bearing shops (CBC, SKF etc) can order a good range of imperial pitch belts.

[mikej65]

I believe that Roman is correct on the 3/16" pitch. This is an old design from the 50's or 60's and was know as an F profile. There were never any standard sizes and molds were just purchased for a specific OE project. The bad news is that very few F profile belts are still available and would not be something that an industrial distributor would be able to get for you.

The only chance of finding a 118T F would be a parts source for a specific piece of equipment that used it and is buying mandrel quantities from someone who still has a mold. Uniroyal did make this size and Gates might still have the mold, but they would not stock the part or make less than mandrel quantity (maybe 35 belts).

I would suggest adapting an XL, T5, or HPPD 5mm drive. You could turn down the existing large sprocket and mount a ring machined from a stock sprocket over it, or buy a piece of aluminum barstock and machine the V-grooves in it.

Mike

[rusel]

RomanLini
Have been to those two bearing shops, no dice there
Mike
What you say make sense, but it sound like I am 40 years to late. When I brought the lathe new I did not know I was buying a antique.

Looking at replacing the timing and vee pulleys

Russell

[rusel]

Al
Did you put your sons lath up grade in the forum or some wear I can see it.
Seriously looking at going in that direction.If I am going to spend money on pulleys and belts to have the old might as well spend some more and update it.

Russell

[RomanLini]

...
This is an old design from the 50's or 60's and was know as an F profile. There were never any standard sizes and molds were just purchased for a specific OE project. The bad news is that very few F profile belts are still available and would not be something that an industrial distributor would be able to get for you.
...

I wonder how much the profile actually matters in this case. Maybe another profile in 3/16" pitch would still work fine as long as the belt teeth fit in the pulley. Even if you get a slightly longer belt and adapt the motor mount that's still looking much easier than a double pulley retrofit.

Just suggestions.

[mikej65]

I wonder how much the profile actually matters in this case. Maybe another profile in 3/16" pitch would still work fine as long as the belt teeth fit in the pulley.

The problem is that there is not another 3/16" belt out there. Standard pitches in this range are the .200" XL and several 5mm profiles. From there it drops to MXL at .08" and some 3mm profiles.

[Al_The_Man]

Al
Did you put your sons lath up grade in the forum or some wear I can see it.
Seriously looking at going in that direction.If I am going to spend money on pulleys and belts to have the old might as well spend some more and update it.

Russell

I could post a photo of the spindle, we originally went with a DC servo motor with tach feedback using a KB DC SCR controller, this worked fine, but it now has a Fanuc AC servo motor with encoder feedback for C axis control, the Fanuc motor was something I wanted to experiment with.
A new mounting plate was made to use the servo mounting rather than the foot type of the original AC motor.
Al.

[rusel]

Al
We where looking a AC three phase motor with a VFD controller and a encoder feed back on spindle. We are thinking of cnc the rest of the lathe latter.
Reuse the cone vee pulleys to stay in the motor sweet spot.
What are your thoughts on this layout?
Russell

[Yindee]

Belt available from Sidermeca (contact@sidermeca.com) pitch 4.65 mm width 15mm belt model SAV6125/P6.35 around 19 Euro a piece. I purchased one a couple of months ago.
Cheers
Gerard

[rusel]

Hi back again
Have sourced and put on a 3 phase motor on to lathe.
As you can see in photo I had to temporally set up the pulley so that I could bore out the motor pulley to fit lager shaft size. VFD worked well on this first use.
The second photo show original motor where there was only 11.5mm of shaft and 4 mm of key going into the motor pulley.

I guess that motor shaft is expensive in China

Will fit VFD in next few days. Then to tune it in.

Russell

[Al_The_Man]

Bit late but here are the pics of the Fanuc motor conversion, the small circuit board is the pulse detector to sync the threading using the spindle encoder.
in conjunction with the Z.
Al.