Author Topic: Myford VM-B CNC Conversion.  (Read 11412 times)

Offline John Stevenson

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Myford VM-B CNC Conversion.
« on: October 04, 2011, 04:30:00 PM »
So got most of the big bits of a VM-B from the Myford sale for 100.
Brand new but well shop soiled and robbed.
No motor, spindle, pulleys, covers etc
Main bits are base, saddle, bed, screws and head.

problem is this is a right backwards arsed design as where the spindle locates.



Rough assembled with a lump of tube to represent the missing spindle.



Right at front of travel with a plate on bed that it will need to machine, plate is 150mm or 6"



Full back and it overhanging the bed.

Shot inside the head showing how cored it is, no spare metal anywhere.




I can squeeze another 15mm to give me 165mm but the problem is the spindle hole is in the wrong position, plus I don't have a spindle anyway or any of the drive mechanism.

So this is the bit that poses the problem.



So a bit of hacksawing, not shown, a bit of angle grinding, definitely not shown due to artisic license and a bit of surface grinding.




Only shown because they show it on tele and it's only microns being killed <g>

And we get this:-





The motor in the picture is only a slave for pics, new motor ordered.

After searching all the motor specs we can get a 1.1Kw [ 1.5HP ] motor in a reduced 80 frame size at 2800 rpm [ remember we are on 50 Hz ]
80 Frame means 80mm from feet to centreline, that one in the pic is a 63 frame.

So if we run a 2 pole motor at 120 hz which they will stand, they are good for 6,720 which is about the right speed for a 3mm drill.

At low speed usuable torque on a 1.1Kw motor is about 20 Hz giving a low speed of 1,120 rpm.

Not much use for a manual machine but for a CNC only using small cutters this spread is ideal.

So plan B is to strip the new motor when it comes, make a new end up out of solid alloy as most motor ends now and very skimpy, fit a double row angular contact bearing that held in place by a keep plate.

Press the shaft out and make a complete new shaft to take ER 20 collets, because the bearing won't be able to go over the collet chuck bit the rotor will have to be modified to be a push fit, not press fit and have a keyway and retaining nut to hold it in position.
Many grinder rotors are built this way.
Get the rotor re-balanced and rebuild the motor.
motor then bolts to a conversion plate between the cut down head and the motor.

Ballscrews are on order from China, motor should be here later this week or early next week.


John S.
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John Stevenson

Offline Swarfing

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Re: Myford VM-B CNC Conversion.
« Reply #1 on: October 04, 2011, 04:57:26 PM »
John if you ask nicely the Chinese collet chucks can be had with different dimensions than the standard ones they sell. I did inquire and they said they could do that for me for an extra 15...bargain. In the end i found one already with a 10mm shaft so changed my design a little to suit. Forgot his name but the one that sells all the ballscrews and kits is the man. I think you should know the one i mean.
Once in hole stop digging.

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #2 on: October 04, 2011, 05:24:17 PM »
Yes got a few of them kicking about but I need a collet chuck that has the same bearing diameters on it as the motor, plus the rotor bore with keyway and a thread for a lock nut to hold the rotor on.

Long short it will be quicker to make a complete new shaft to suit.

John s.
John Stevenson

Offline Swarfing

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Re: Myford VM-B CNC Conversion.
« Reply #3 on: October 04, 2011, 05:55:40 PM »
See what your saying now you put it like that.
Once in hole stop digging.

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #4 on: October 05, 2011, 01:30:05 PM »
Cool project John  :thumbup:


Is that a swing grinder your using there ?,,,,,must have missed that at your shop

How many division plates are you planning to make  ::)


Rob

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #5 on: October 05, 2011, 02:35:02 PM »
Outside just outside the door under a sheet.
It's a very dirty machine and I don't want it inside, best out in the open with all that dust and crap.

We make 4 different styles of plates, some are in sets of 4, some in sets of 3 and some singularly. No matter what type the blanks are laser cut in 100 quantities and they don't last long.

Been making these for quite a few years now and often wonder where they all go.

All the plates are different to standard plates in some way, typically 127 holes added or the small set for watchmakers has weird numbers of holes.

John S.
John Stevenson

Offline doubleboost

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Re: Myford VM-B CNC Conversion.
« Reply #6 on: October 05, 2011, 05:12:25 PM »
Looking good john :thumbup: :thumbup:
It must be the time of the month for cutting up milling machines :bugeye: :bugeye: :bugeye:
John

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #7 on: October 08, 2011, 09:02:11 AM »
Next instalment, as I said this is only being done on Tuesdays and Fridays as it's the only time my Grandson can get down.

Still awaiting ballscrews etc so got the motor today.



Bog standard 1.1kw, 1.5 HP motor and stripped it down, nothing to these, cover off, fan off and an end shield then pop the rotor out.



Original bearing on left, similar but double row angular contact on right.
One thing to note with these new inverter metric framed motors is the absence of slots in the rotor. These are now coming out with the allow 'winding' pressure die cast into internal slots so the outside of the laminations is uninterrupted, less chance of flying out at high speed.



Shaft pressed out the rotor, keyway broached in and set around the rotor are the existing bearings, two different sized angular contact bearings, existing 20mm and the one I'm going to use at 25mm bore plus a collet and nut for ER25.

I was going to use ER20's but on checking I don't have collets for ER20's so it was a choice of 16's, 25's or 32's so 20's won out.


Next step is to make drawings up of the existing motor so the details can be transposed without cutting metal. This is the existing motor as an accurate drawing.



Drive shaft is on the right.

Same drawing with the modified nose superimposed on it.



Because the bearing can't go on over the collet nose it's designed to assemble the opposite way and the bearing is held into the front cover by a keep plate so it's held firm with no end float.

This means the rotor will have to assemble onto the shaft after hence the keyway for a sliding fit as opposed to a press fit and a nut on the fan end to secure it all.



Next job is to copy the spindle, spacer, nut and end cover from the second drawing and dimension up [ only part done so as not to crowd the drawing ] We now have all the details we need to start making the spindle on Tuesday.
John Stevenson

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #8 on: October 08, 2011, 01:38:49 PM »
Dam interesting John  :smart:

Clever too  ::)


Rob


Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #9 on: October 12, 2011, 02:29:15 PM »
Next instalment, as I said this is only being done on Tuesdays and Fridays


What happened ! :whip: :poke:


Rob  ::)

Offline Stilldrillin

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Re: Myford VM-B CNC Conversion.
« Reply #10 on: October 12, 2011, 02:38:50 PM »
Next instalment, as I said this is only being done on Tuesdays and Fridays


What happened ! :whip: :poke:


Rob  ::)

Slave driver........  :lol: :lol:
David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline doubleboost

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Re: Myford VM-B CNC Conversion.
« Reply #11 on: October 12, 2011, 04:06:46 PM »
I reckon you have blown the warranty on that motor :bugeye: :bugeye:
Looks good  :thumbup: :thumbup:
John

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #12 on: October 12, 2011, 05:00:38 PM »
Grandson had his 6th form meeting at school last night and I'm working like crazy getting ready for the Warwick show so every thing is on hold until a week on Friday.

I didn't know about the meeting until too late.
Good news is the ball screws are in, not bad 9 days from China and under the radar as well  :wave:

John S.
John Stevenson

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #13 on: October 23, 2011, 08:53:34 AM »
OK, catching up.
Tuesday was out this week because of the show so only Friday available.

Now got the drawing for the spindle from the previous sheets so lump of metal cut and front bit of the spindle machined.

Simple machining, bore the taper , thread for the nut. Next bit is the crucial bit and it's stood me in good stead making quite a few similar spindles.

Remove from the chuck and replace with a bit of Scrapbinium [TM ] turn this down, in this case to 16mm so the largest ER25 collet can grip on it.



Then carefully drill the tail centre hole, do this at low speed so the shaft doesn't whip, once the centre has been drilled and supported the shaft can be belted down to size.
I tend to turn everything down with 1/2 a mill left on for final cutting, the reason behind this is that the shaft is constantly getting hotter as you block the bulk out. Once cool then reset the tail centre as it will have moved moved under expansion and turn to finished size.

This is state of play at the moment.



I need to make the new end housing up, do a quick assemble, check for run out then send for Tuftriding, then final assemble and test run, hopefully by the end of this week and I can get back onto the main frame fitting screws etc.

John S.
John Stevenson

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #14 on: October 23, 2011, 09:34:12 AM »
Is that it ,,,,,,,,,,,,,its been 2 weeks   :coffee:

Rob  :wave:

Offline Ned Ludd

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Re: Myford VM-B CNC Conversion.
« Reply #15 on: October 23, 2011, 10:11:16 AM »
Hi John,
My hero. :bow: :D
Ned
I know enough to do what I do, but the more I know the more I can do!

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Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #16 on: October 23, 2011, 11:39:21 AM »
Is that it ,,,,,,,,,,,,,its been 2 weeks   :coffee:

Rob  :wave:

Done a show in between and had to take the piss out of a few Geordies, as you know that takes a lot of effort getting the thick bastards to understand they have been had  :scratch:
John Stevenson

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #17 on: October 23, 2011, 01:35:01 PM »
Is that it ,,,,,,,,,,,,,its been 2 weeks   :coffee:

Rob  :wave:

Done a show in between and had to take the piss out of a few Geordies, as you know that takes a lot of effort getting the thick bastards to understand they have been had  :scratch:


 :lol: :lol: :lol: :lol: :lol: :lol: true very true  :doh: :lol: :lol: :lol: :lol:

I do like the way you machined the spindle  :med:

Rob

Offline DICKEYBIRD

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Re: Myford VM-B CNC Conversion.
« Reply #18 on: October 24, 2011, 04:45:44 PM »
...do a quick assemble, check for run out...
I'm keen to hear how much runout you end up with John.  I turned down the 1 1/4" straight shank on a CTC ER32 collet chuck to 30 mm using the same method as you (other than screwing a bolt into the plain end and center-drilling it) and ended up with .0015" runout.  I guess I should have turned a 8 deg. tapered stub to fit the chuck instead of relying on a collet to be close to perfect. 

I've now skimmed the taper in-situ and still have .0004" or so. :doh:
Milton in Tennesee

"Accuracy is the sum total of your compensating mistakes."

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #19 on: October 26, 2011, 04:02:32 PM »
Managed to get all the bits back and assembled the motor tonight.
Just sat on the bench with a collet and drill blank in the collet and turning by hand i get about 1/4 of a thou run out right on the end.

End housing is just a solid lump of alloy bored for the register and bearing so seeing as it was so thick I belted two 26mm holes in for headlights.



Two 5v CREE LED lights from China, dead bright these are you can weld with them.

Switched off all the lights in the shop and switched these on pointing across the shop.



That's just these two lights. Took another picture with the motor jacked up as though it is working but all you could see was two overlapping orbs so i had to shine the lathe work light over towards the bench to get some background lighting.



Now got to sort an inverter out and test run the motor, bought a big box of 10 surplus inverters a while ago and can't find the damn box.............................

John S.
John Stevenson

Offline doubleboost

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Re: Myford VM-B CNC Conversion.
« Reply #20 on: October 26, 2011, 05:50:10 PM »
That looks very nice
I played around with those led units in cap lamps very bright nice stable light
Only problem was they got very warm
John

Offline HS93

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Re: Myford VM-B CNC Conversion.
« Reply #21 on: October 26, 2011, 06:06:17 PM »
have you got a link to the lights.

Peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #22 on: October 26, 2011, 06:51:21 PM »
Link:-

http://www.dealextreme.com/p/cree-q5-led-drop-in-module-3-7v-18v-input-11621

They have an inbuilt regulator and will take 3.7 volts to 18 volts.

Full operating voltage is 5 volts, anything over 5 volts gets turned to heat, run them on 5 volts, I use a Nokia phone charger rated at 350mA and they will run all day with no heat. Got about 5 or 6 fitted to machines and at the end of a day you can hold them in a closed fist and they are just warm.

John S.
John Stevenson

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #23 on: November 06, 2011, 06:52:14 AM »
Friday nights episode.

New inverter wired up and test run.



Backed off to 6,000 drops the noise a bit which is mainly fan noise, might pay me to reduce the fan diameter but see how it runs and cuts first.

Conversion plate made and bolted to the head casting with countersunk screws and motor fitted.
need a new set of holes drilled as it's about 40mm too high, not a problem.



State of play at the moment, ball screw fitted roughly, conversion plate needs a tidy up as regards cutting the width down, radius corners etc.

Tuesday night job is to make a top plate that will support the stepper inside the column and carry a bearing block for the top of the ball screw.

Been drawn up and belts and pulleys, 2:1 reduction, HTD 5M, on order.

John S.
John Stevenson

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #24 on: November 11, 2011, 03:49:04 PM »
Hi John

Your sure getting a fare old lick out of the motor  :bugeye:  ,,,,,Did you do anything with the fan ?   



Rob

Offline HS93

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Re: Myford VM-B CNC Conversion.
« Reply #25 on: November 11, 2011, 04:07:45 PM »
have you got a link to the lights.

Peter

Thanks for that

Peter
I am usless at metalwork, Oh and cannot spell either . failure

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #26 on: November 11, 2011, 04:29:23 PM »
Hi John

Your sure getting a fare old lick out of the motor  :bugeye:  ,,,,,Did you do anything with the fan ?   

Rob

No same fan but I reckon I can trim it down a bit to quieten the motor, getting a fair bit of wind noise, either that or it's the curry.

Nothing done tonight, grandson has injured his knee playing rugby again, about time his team bout a ball instead of using him....................
John Stevenson

Offline doubleboost

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Re: Myford VM-B CNC Conversion.
« Reply #27 on: November 11, 2011, 05:39:14 PM »
Hi
John
Ntcely done  :thumbup: :thumbup:
Like Rob says you have got some revs out of that motor
Warranty is nackerd now :lol: :lol: :lol: :lol:
John

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #28 on: November 11, 2011, 06:17:05 PM »
Hi
John
Ntcely done  :thumbup: :thumbup:
Like Rob says you have got some revs out of that motor
Warranty is nackerd now :lol: :lol: :lol: :lol:
John

No way, still got 10 year warranty on it, I do too much work for the motor importers for them to upset me  :wave:
John Stevenson

Offline doubleboost

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Re: Myford VM-B CNC Conversion.
« Reply #29 on: November 11, 2011, 06:34:53 PM »
You would have :clap: :clap:
I remember years ago we were racing in formula atlantic
Using cosworth 1600 bda engines
We were using standard ford escort starter motors but giving them 24 volts :Doh: :Doh: :Doh:
By the bastards used to spin
Had a load of warranty claims (we were lucas dealers) :Doh: :Doh: :Doh:
John

Rob.Wilson

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Re: Myford VM-B CNC Conversion.
« Reply #30 on: December 23, 2011, 08:10:16 AM »
Is this project finished John  :poke: :whip:


Rob  :coffee:

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #31 on: December 23, 2011, 09:08:10 AM »
Gimme 10 minutes  :wave:

Doing it with my grandson and he's had to miss the last few weeks due to other commitments.
Only night he managed to get over we spent sorting the hay loft out so i could cram another two CNC I had bought up there out the way.

John S.
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Offline DICKEYBIRD

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Re: Myford VM-B CNC Conversion.
« Reply #32 on: January 16, 2012, 10:15:44 AM »
Yer 10 mins are up John.  Go on, you've pharted around long enough with this thing.  We wanna see it drill some holes.  :poke:
Milton in Tennesee

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Offline mexican jon

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Re: Myford VM-B CNC Conversion.
« Reply #33 on: September 14, 2015, 08:36:50 PM »
Did this ever get finished  :scratch: :scratch:
People say you only live once ! I say thank F@*K can't afford to do it twice.

Offline John Stevenson

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Re: Myford VM-B CNC Conversion.
« Reply #34 on: September 15, 2015, 04:47:04 AM »
Still slated to be finished but in the meanwhile I bought a complete CNC workshop for a college who were packing in, slowly been doing these as conversions and selling them on.
Only got 4 more to finish   :headbang:
John Stevenson

Offline BillTodd

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Re: Myford VM-B CNC Conversion.
« Reply #35 on: June 03, 2017, 12:02:57 PM »
John, 

Did you ever get around to testing your spindle?

I was thinking of a similar conversion to add a Z to my xyz edge 2axis Bridgeport copy.

Bill