Author Topic: Advice on buying a vertical mill.  (Read 7651 times)

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #30 on: March 11, 2018, 11:08:26 AM »
I'll use it to do 'full sized' stuff as well as model engineering, which is what I found attractive about the 40 INT  spindle nose.  My poor old 3 MT boring head jumps about when I bore a 4" hole.

Power feed on the X axis is a requirement but I don't mind so much about the other two.  DRO is a necessity too but not important on the quill, although I could fit a cheapy from eBay if I thought it necessary.

I agree about spares Jason, but I'm not going to be using it in an industrial situation so don't think they are a huge consideration are they?  It looks hugely chunky compared with the Bridgeports on offer for a lot more money, does it not?  Who sold it originally and how old is it?

I expect I'll get a reply from G and M tomorrow and will be interested to hear what they say about it.  I've looked up Hartford 5KV3 on Google but can't see any full specs including dates when it was available and dimensions.
John Fearnley

Offline Alyn Foundry

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Re: Advice on buying a vertical mill.
« Reply #31 on: March 11, 2018, 11:11:06 AM »
Good morning John.

It's a nice machine. Far Eastern, and " generic " spares readily available. It's virtually the same machine I used to use at Chester UK.

As I see it your problem will be the motor. At 5 KW it'll be right at the top end of your static phase converter. I'm also pretty sure the motor doesn't have the " Star point " available to use a VFD.

The " vari speed " heads are marvellous, two speed mechanical with an infinitely variable belt drive over the low and high setting.

They are very robust machines.

Cheers Graham.

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #32 on: March 11, 2018, 11:43:23 AM »
Morning Graham!

I should have told you the casting arrived safely!  I'm part-way through machining it.

Thanks for the input and reassurance about spares.  My Transwave converter is 7.5 KVA capacity and powers the Bantam with its 4 HP motor on no5 of 8 output settings - I just checked to make sure - so I shouldn't have a problem?  Its a pain not having 3PH - we have 2 phases coming onto the property at 440V or whatever and the big welder , being an auto-transformer, uses the higher voltage.  I enquired about having 3PH brought in but apparently the local transformer would have to be changed and the cost to us several years ago would have been somewhere in the region of £10K.

John.
John Fearnley

Offline Alyn Foundry

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Re: Advice on buying a vertical mill.
« Reply #33 on: March 11, 2018, 03:19:54 PM »
Hi John.

Glad to read the OEM part arrived safely.  :)

Two phases, that's unusual but, I'm pretty sure there are VFD's that can convert a 415 two phase input into a 3 phase ( 415 volt between phases ) output, advice from a supplier should be sought.

The beauty of modern VFD's is the efficiency, up to 98% against 50% with static phase converters.

With the milling machine in question, a 50 HZ output is all that's required as the machine itself has variable speed with the belt.

Cheers Graham.

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #34 on: March 11, 2018, 04:21:27 PM »
I'll speak to someone Graham.  I don't know much about our supply apart from the fact that the previous owner (a farmer who had been here since it was put in) called it split phase when I moved here in the 60s.  There were one or two enormous (for their HP) electric motors driving barn equipment and a water pump, and half the domestic supply is on one phase and the other half on the other to share the load.
Apart from the proposed mill, we have a large 3PH hydraulic press that we were given but have never used, so its worth finding out a bit more.

Carb casting is coming along.  Don't you just love machining cast iron - its so satisfying!

John.
John Fearnley

Offline Tennessee Whiskey

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Re: Advice on buying a vertical mill.
« Reply #35 on: March 12, 2018, 09:20:05 AM »
John, don’t know if something like this available on your side of the pond, but, I use one on my Bridgeport clone and Monarch 10ee and have had no complaints or problems.

https://www.americanrotary.com

Cletus

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #36 on: March 12, 2018, 11:29:17 AM »
Thanks for that Cletus.  I'll investigate whether they are available over here, but if they aren't there are several makes of rotary ones that are.  I'd have to take advice on which I would need - which model do you have?  Reading the AR Series specs, presumably I'd need one that will start 5HP on an easy start as a mill running light wouldn't be a hard one?  Like that the 7.5 would do.  I'm also bearing in mind that it wouldn't be in constant use as in an industrial situation.  Some weeks it might work most days for an hour or two and other weeks not at all.  I'll also ring Transwave and ask what my present one is capable of.

John.
John Fearnley

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #37 on: September 27, 2018, 09:43:02 PM »
Having been sidetracked for months, I'm finally back to making a decision about the mill!  Today I've been to Leicester and then up into Staffs to look at some used turret mills.  The choice seems to be between  a very nice, little used one with R8 tooling, 1998 vintage, and a very similar but not quite so pristine 1998 Excel machine with 40 Int spindle nose.  Both have 2 axis DROs and variable speed drive and are around £4000 plus vat delivered.  The R8 machine has power lift to the knee and its slides and table are absolutely pristine, the 40 Int one appears to be very nice but isn't quite as pristine, as I say, and the price is £300ish more delivered.
Both machines seem very hefty compared with the old lady I've been using, but is there any big advantage in having the 40 Int tooling?  Is it much more rigid than R8?  Does the little pin break so the R8 drive isn't positive - eg when using a boring head on biggish holes?  I have used mine on occasion to bore a 100mm hole in steel, and that was with a boring head with 3MT shank.
I've said I'll make a decision over the weekend, but I'm totally confused, so any advice will be gratefully accepted! 
Thanks in advance, John.
John Fearnley

Offline jadge

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Re: Advice on buying a vertical mill.
« Reply #38 on: September 27, 2018, 10:31:52 PM »
In theory INT40 will be much more rigid than R8. But it depends upon the rest of the mill. My Bridgeport (R8) is versatile but not especially rigid. I doubt it would be much better with an INT40 taper. On the other hand my horizontal mill, with INT40, makes a brick built outhouse look flimsy and can make use of the INT40 taper. It didn't even cough taking 2mm depth of cut and 8 thou per rev feed in cast iron swinging a flycutter at 9" diameter.

By the way the little screw in the R8 taper isn't a drive pin; it's purely to stop the collet rotating when tightening the drawbar. The taper transfers power solely by friction. On both my R8 taper mills they're broken and I don't miss them in the slightest. I've bored 3.5" holes in steel on the Bridgeport without a problem.

Andrew

Online Jo

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Re: Advice on buying a vertical mill.
« Reply #39 on: September 28, 2018, 07:51:13 AM »
The other thing to bear in mind is the availability of tooling: R8 is hard to come by, in comparison 40 Int is much easier.

Both of my larger mills are set up for using 30 Int tooling in the early days that was like Hocking horse do-das to find but thanks to CNC (and Flea bay) that is much easier to find these days.

Jo

P.S. 40 to 30 Int converters are available  ;)
Enjoyment is more important than achievement.

Offline Manorfarmdenton

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Re: Advice on buying a vertical mill.
« Reply #40 on: September 28, 2018, 07:18:16 PM »
Thanks Jo and jadge.  Interesting re the screw /pin in the R8 socket.  They were missing in most of the mills I looked at.  I hadn't thought much about availability of tooling but did ask for an ER32 collet chuck to be thrown in and both vendors agreed to supply new ones - I have a full set of ER32 collets that I use with my old 3MT mill.  I think I'd also get holders for my Clarkson imperial and metric collets in either deal.
As regards rigidity, the two machines are very similar in build apart from the spindle, but the R8 machine is 3hp while the 40 Int one is 5HP.  Presumably that's significant as the 40 Int socket is capable of transmitting higher torque?  How much that matters I'm not sure, as jadge says R8 is capable of boring a 3.5" hole and I've done a 100mm one with 3MT?

Another machine I've been offered is a Cincinatti with 40Int spindle, very rigid but it looks as if its seen more use.  It would be about the same money but would have a new 2 axis dro and an additional slotting head.  It doesn't have power to y axis or knee, but that isn't the end of the world.  I don't know - I'm still indecisive!  John.
John Fearnley

 

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