# velocity myford ML7



## troll (Aug 22, 2010)

I have myford ML7 with pulley motor 3 1/2"
Which is the nominal speed? pulley 2 1/2"
thank you


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## Deanofid (Aug 23, 2010)

What is the rpm for the motor?


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## troll (Aug 23, 2010)

I am sorry
1450 rpm 50hz
thank you


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## arnoldb (Aug 23, 2010)

Troll, for 1450 RPM 50 Hz with a 1 7/8" motor pulley spindle RPM is:
   Straight  Back gear
1  200     35
2  357     62
3  640     110

and with a 2 1/2" motor pulley:

   Straight  Back Gear
1  273     47
2  487     84
3  870     152

May I be so bold as to suggest that you invest in a copy of "Myford Series 7 Manual" authored by Ian Bradley ? - it is really inexpensive and worthwhile to have around for your Myford Thm:

Kind regards, Arnold


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## tel (Aug 23, 2010)

I'll second Arnold's suggestion - every Myford owner should have a copy of that book!


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## lordedmond (Aug 24, 2010)

arnoldb  said:
			
		

> Troll, for 1450 RPM 50 Hz with a 1 7/8" motor pulley spindle RPM is:
> Straight  Back gear
> 1  200     35
> 2  357     62
> ...



the smaller pulley was for the babit bearings and the lager was considered the high speed one for the bronze bearings. 640 is the max you want to run with babit main bearings


Stuart


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## Maryak (Aug 24, 2010)

lordedmond  said:
			
		

> 640 is the max you want to run with babit main bearings
> Stuart



Stuart,

I am very curious about the above and why this is so. Many machines with babbit, (whitemetal), bearings run at higher speeds than 640. At higher speed the more likely you are to have hydrodynamic lubrication, without forced lubrication.

Best Regards
Bob


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## tel (Aug 24, 2010)

Mine runs around 750 rpm and has done for many years, quite a lot of my stuff is done at the top speed but there has been no measurable wear thus far. I would think Myford were well and truly erring on the side of caution.


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## lordedmond (Aug 24, 2010)

maybe they were cautious with the speeds , maybe thats why they last well
the export ones with 60hz motors ran at a higher speed with the same pulleys due to the faster motor speed 

AFAIK the larger pulley was a high speed option


My big bore runs at 3k rpm buts thats on the bronze taper bearings only two speed ranges tho with back gear only recommended on the lower one .

I do take advantage of the higher RPM eg today I was extracting a petticoat pipe out of a 3 inch length of 2 1/2 dia brass at 1500 rpm using HSS zero top rake of-course

the book mentioned in earlier posts dose give the normal spindle speeds

Stuart


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## BenPeake (Aug 25, 2010)

I have altered the speed of my Myford ML7 by doubling the diameter of the pulley attached to the motor. I've found this to be really good for turning small diameter work and I've also found that the range of speeds I now have is much more useful. However, I did run into some trouble with the countershaft bearings. They were bronze bearings but were damaged after some use at the highest speed. The shaft was also damaged so I've since re-machined the shaft to accept ball bearings. Since then I have had no trouble at all running my ML7 at higher speeds. If I have any trouble with the main bearings I'll probably investigate doing something similar. Perhaps spindle bearings or something like that are available. I have a picture of the bearings I put in:







Hope this is interesting to someone,
Ben


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## troll (Aug 26, 2010)

Thanks to all
A friend I give myself a meter of rpm
countershaft to 621 rpm
lathe spindle to: 
380 rpm
640 rpm
1100 rpm


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