3000 rpm on a Myford lathe

[firebird]

Hi

I haven't posted much of late but I have been busy. There has of course been the usual round of domestic duties to attend to but my workshop time has been taken up with tooling. Since the completion of my small steam plant and the steam beam engine I have concentrated on making all the little bits and pieces, thick washers, handles, knobs etc that are always needed but never to hand. Plus sorting out storage, making racks and boxes etc. I have also been busy on a major bit of kit that is now getting close to completion. During the course of making the two steam engines, especially some of the smaller parts like stainless steel needles for the valves etc it seemed the Myford simply wasn't fast enough. My mate Julian has 2 of the Chinese lathes, a CO with top speed of 3800 and a C3 model with a top speed of 3000 rpm. Having had the opportunity to use both these lathes and a watchmakers type lathe with a top speed of 4500 rpm I decide I needed something faster. What were the options, go out and buy a new lathe?? No I love my old Myford and wouldn't change it for the world. So I set to and designed a new head stock that would sit on the lathe bed in front of the existing head stock. Belt drive to a counter shaft and then back up again. The new headstock sits on exactly the same centre line so I can use the the same tooling in the same top and cross slide plus of course the same tail stock. Its driven by the same lathe motor by mounting the first gear in the mandrel and taking the drive from there. With the Myford belt in the middle position I now have approximately 3000 rpm at the new head stock. The only down side is the loss of about 6 inches between centres but that's no problem as I will only be turning small short stuff in the new headstock, anything bigger will be machined as normal.

Anyway here's a short video. The modification isn't finished yet, there are belt guards to make and one or two more bits.

Before anybody tells me off for running a machine with no belt guards let me assure you I wasn't machining anything and I was wearing a leather welding apron and safety goggles. I was standing well clear while I switched on for a few moments to shoot the video.

[ame]http://youtu.be/YFnk5FHdmp8[/ame]

Any questions please fire away, I have loads of photos etc.


Cheers

Rich

 

[steamer]

That is a fairly serious bit of kit! And yes no mention of the lack of guarding.


Be careful with that....there's a lot of inertia there.

Dave

 

[MachineTom]

Looks nice, what sort of BB are used in the headstock, annular contacts? Is the RPM rating of the chuck good for 3K. High speed is great for the finish, I use stick lube when cutting, an absolute at those speeds.

 

[Spurry]

Rich

Very clever solution. Put's me in mind of Baldrick, when he says..."Sire, I have a cunning plan...."

Pete

 

[firebird]

Hi

Dave, I will be making a substantial guard that covers everything from the existing head stock to the new one.

Tom, I have used taper roller bearings that are good for higher speeds than I am using. I don't intend to use a chuck just collets. It has been designed to use my existing MT2 myford collets which are closed and held in with a screwed ring. I have collets up to 1/2 inch, I figure anything bigger than that won't need high speed. Can you give me a little more info on stick lub?

Pete, unlike some of Baldricks plans this one works.

Cheers

Rich

 

[lordedmond]

well my Myford does go to 3K rpm as standard ;D

a point on my my ford chucks ( big bore ) they have the safe working sped stamped on and it is 4500 rpm, I would be a bit wary of the standard 1 1/8 nose chucks at that speed.

also the new back plates have a safety screw in them to prevent spin off, it not for using in reverse if the shaft stops at 3K then the mass of the chuck will continue to try and turn , result fly away chuck


good project though but do consider the speed ratings of the parts and the spin off problem


Stuart

 

[firebird]

Hi Stuart

As stated above I don't intend to use a chuck, only collets. I had thought of potential spin off problems at the design stage. My thinking is that any work piece big enough to require a chuck won't need the high speed so will be machined using the standard speeds and original head stock/spindle. Its a good point though and worth emphasizing.

Cheers

Rich

 

[arnoldb]

:bow: :bow: Rich, that is just brilliant :bow: :bow:!

I agree about checking for spin-off - but it's always the small things that need a wee bit of speed which our ML7s don't have, and for collet chucks this is just dandy.

There's an additional advantage to your solution. It gets away from the headstock a bit and will use some of the less-used bed for working; I don't know about your lathe, but mine is definitely a lot "looser" on the apron close to the headstock, as a lot of small parts are made there and wear is the highest on the bed there.

;D Oh, and don't be too jealous of the high speeds - when it comes to needing slow speeds (for threading and turning BIG bits close to the lathe's limit), I do consider the ML7 to be a good girl; very few new lathes of a similar size will go down as slow as 35RPM with maximum torque like ours does Thm:. The problem is the electronic speed controls; I found that already with my additional "small" lathe; runs great at 1000+ RPM, but no torque below that because of the variable speed control. Guess it'll get back-gearing as well!

Stuart, you're fortunate ;D - Super 7 ?

Kind regards, Arnold

Kind regards, Arnold

 

[firebird]

Hi Arnold

I agree. One of the new skills I had to learn while making this was screw cutting, the 1 1/8 thread on the nose for instance. The high torque and low speed made it a lot easier. Another was line boring the two holes for the taper roller bearings, and then there was turning the large blanks to make the two 90 tooth pulleys.

Anything anyone wants to take a closer look at just shout up and I'll post some pics.

Cheers

Rich

 

[tel]

Looks a good, workable solution to me - that 700 odd rpm top speed has always been a limiting factor with my ancient, but well beloved Myford!

Put up some pics by all means - I, for one, would like a closer look.

 

[Mosey]

50 to 1375 on my South Bend 10K. 3000rpm? Sounds great.

 

[lordedmond]

:bow: :bow: Rich, that is just brilliant :bow: :bow:!

I agree about checking for spin-off - but it's always the small things that need a wee bit of speed which our ML7s don't have, and for collet chucks this is just dandy.

There's an additional advantage to your solution. It gets away from the headstock a bit and will use some of the less-used bed for working; I don't know about your lathe, but mine is definitely a lot "looser" on the apron close to the headstock, as a lot of small parts are made there and wear is the highest on the bed there.

;D Oh, and don't be too jealous of the high speeds - when it comes to needing slow speeds (for threading and turning BIG bits close to the lathe's limit), I do consider the ML7 to be a good girl; very few new lathes of a similar size will go down as slow as 35RPM with maximum torque like ours does Thm:. The problem is the electronic speed controls; I found that already with my additional "small" lathe; runs great at 1000+ RPM, but no torque below that because of the variable speed control. Guess it'll get back-gearing as well!

Stuart, you're fortunate ;D - Super 7 ?

Kind regards, Arnold

Kind regards, Arnold

Arnold

Its not a super 7 its a connoisseur complete with inverter drive as standard

 

[firebird]

Hi

Stuart, you are a very lucky man.

Ok a few pics of how it all started. For quite a while I was stumped on how to make the spindle. It would of course have to be accurate, hard and have a 2 MT. I looked into all ways of how to machine one but I was really stuck until one day I was working on my mill which is an R8. I have an adapter which takes it to 2MT so I can use some of my other tooling and when I took it out the draw everything suddenly fell into place. Checking its dimensions its largest diameter was even the same size as the Myford nose. They are not that expensive to buy at £9.50.

First job was to get it very accurately centred in a 4 jaw chuck.



Then turn down to 1 1/8 with support from the tail stock.



Then screw cut.



It then has to be reversed in the chuck and set up accurately again



Then turned down to 24mm. Its just under 25mm diametre, a standard sizefor taper roller bearings, so I had to turn it down to 24mm and source some bearings of that size.



A trial fit of a bearing.



The spindle is quite hard. I trashed a couple of TCT inserts and had to face up the screw cutting tool a couple of times.

More to follow

Cheers

Rich

 

[Davo J]

Great idea and turned out nice.
It's amazing how people go on about guards, when years ago we had none or very little guarding.

Dave

 

[firebird]

Hi

Thanks Dave.

Here's one I forgot to show re the spindle. Screw cutting a 32 TPI thread on the other end. This will take a screwed collar which will be used to adjust the bearings.



Cheers

Rich

 

[steamer]

Great idea and turned out nice.
It's amazing how people go on about guards, when years ago we had none or very little guarding.

Dave

Yeah I know...but big brother and the lawyers love it... ;D

Dave

 

[firebird]

Yeah, tell me about it Dave.

At work we are being plagued by the council, health and safety etc etc. It'll get to the point where we won't be able to get anything done but that's a debate for another place I think.

The head stock I made from 1/2 thick steel plate. The base has a fixed and an adjustable strip underneath which sits between the lathe beds. These were adjusted until it was a nice snug fit on the bed. The idea is that once adjusted and set up I can fit the high speed head stock to the lathe in less than 3 minutes.





The rest of the head stock is then fabricated from 1/2 steel plate and 6mm cap head bolts.



the head stock is held onto the lathe bed with 2 clamp plates that sit underneath the lathe shears.



With the head stock fabrication complete it is fitted to the lathe with the 2 clamps just nipped up enough to allow the head stock to slide up and down the lathe bed which has been well oiled. The head stock is now fixed securely to the cross slide with a strap.



Boring for the bearings started with a centre drill and then increased to the biggest drill I have which is on a 2mt shank fitted directly into the mandril. Drilling is by moving the carriage up and down the bed taking the new head stock with it.





Then I changed to a boring head fitted into the lathe mandril but now I used the lead screw to drive the carriage up and down.



Here's a video of the boring operation.

http://youtu.be/ktD7-AQpUj4

Final cuts were taken very lightly until the taper roller outer race just started to enter the hole. There is no room for error on this part of the operation. Just .001 too much and the bearing will be too loose.



Cheers

Rich

 

[arnoldb]

Good going Rich ;D

Keep the pictures coming; I'm also watching!

Kind regards, Arnold

 

[tel]

... as am I - with bated eyes!

 

[firebird]

Hi

Here's a few more photos.

The outer bearing races need a shoulder to press up to. I turned a piece of thick walled aluminium tube



To be an absolute dead fit in the head stock.



Set up in the mill and drilled and tapped both ends 5mm.



Using the same coordinates the head stock was drilled 5mm.



Fitted in



A trial fit of the bearings and spindle



The spindle needs a larger diameter collar at the nose end. A collar was turned with a bore a few thou undersize.



And then pressed onto the spindle. Its purpose will become apparent shortly.



Cheers

Rich