Need Help!- Need your opinions please on which of these mills would you buy?

[Oldmanandhistoy]

Hi,

I'm looking for your opinions, advice or alternatives to which of these I should buy.

1, http://www.optimum-machines.com/prod...rio/index.html

2, http://www.chesteruk.net/store/model_t_universal.htm

3, something like this http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=220377266773

4, other alternatives your suggestions but please keep in mind I'm in the UK

Will they be up to the task?

Purpose of the mill will be for prototyping and very small run (10 of) production in 6082 T6 aluminium. Mainly 2.5D simple small parts.

All the options will need CNCing which I will under take, which is not a problem and the 3rd option will need reworking and updating.

Why not a Bridge port?

This machine will be in my home workshop and there just isn't enough space.

If you need more information please let me know.

Any and all advice appreciated,

John

[tobyaxis]

I would buy the Knee Mill. It has both Horizontal and Vertical abilities with the added advantage of the Knee for raising and lowering the table.

http://www.chesteruk.net/store/model_t_universal.htm

Good Luck

[DareBee]

I am with Toby - wouldn't think for a second on the other 2.

That machine is 3X the machine of the other new one.
Travels, weight, max Z clearance, etc.

And the ebay machine! I have had machines similar vintage and capabilities.

No3 Morse Taper. Spindle Speed 75-775

For what you want to do these 2 items alone should make you run screaming.
Small aluminum parts need high spindle speeds and morse taper tools (for a mill) like to fall out in the middle of a cut.

[Oldmanandhistoy]

Thanks for the replies,

I think the Ebay machine was a poor choice it was the first mill I came across.

As with all the machines I listed the rpm's are not ideal for aluminium and the idea was to replace motor, bearings and control gear on the second hand machine. A machine with a more suitable taper would also be necessary. But the idea was to start with quality iron and spend the necessary funds and time to bring it to spec.

As the bench top machine has a 2.2 kw (3hp) motor I had planed to increase the spindle rpm's and still have the extra torque. Main concern with this machine is the rigidity which may be enough for Ali?

The knee mill would be my first choice also but I don't presume to be always right so thought I would put it to you guys. Again the spindle is the usual low rpm 3000 and only 2hp.
Do you think increasing the rpms at the cost of power is worth considering?

I'm still searching for other possibly alternatives and may even look at building a machine myself.

Anyone else?

[DareBee]

Do you think increasing the rpms at the cost of power is worth considering?

Double edged sword.
Answer to your question considering your application is YES.

The answer to the big picture is "fried spindle and bearings"

If I had to bet on it, I would figure the spindle bearings to be rated 4000-4500RPM. You will likely be able to add this 30% with a reasonable amount of money. At that point I suggest living with it. If your "work load" is greater than that you should be looking at a "real" VMC anyway. Remember that the machine doesn't have ballscrews and the ways are not designed to deal with continuous high speed movements.
ROI needs to be carefully considered. Machine life and output speed are hard to figure.
You will maybe be 10k (USD) and months work to have that machine purchased and in "production"
This machine is 20K

Fadal VMC 3016 HT
1998
10K Air Oil Spindle
High Torque Pozi Drive Spindle
Rigid Tapping
422K Expanded Memory
-5 CPU
CAT 40
21 Position Tool Changer

Will this machine do your parts 30,50, 100 times faster?
Will the ATC and rigid tapping allow the machine to run unattended and/or create less hand work?
This machine should out last the other one.
Over a 5 year period what is the dollars per part cost to repay the machine?

This machine will be in my home workshop and there just isn't enough space.

I know.. I know.. I am babbling

I guess my point is, take what you will get for what it is.
Otherwise get the VMC and build a room for it.

[Oldmanandhistoy]

Thanks DareBee for your time, it is very much appreciated.

The point of this purchase is for R&D and there is a possibility I wont even CNC it.

A VMC, full size workshop plus the fully qualified operators will come after and maybe closer to the end of this recession if all goes to plan.

All I need is a machine to cut aluminium, fit in my workshop and produce a few finished products for market research.

I'll go away and look for other possibilities but it's looking like the Knee mill is going to be the way I go.

Cheers,
John

[DareBee]

You been around here for awhile. I know that you know your stuff.

My words often take a bit of a harsh tone but I have got myself into way too many situations where I should have spent more money up front to save money in the long run.
If I was flexible enough to kick myself in the ass, I would be pretty sore some days.
Just trying to help not discourage.
That model T universal looks like a nice little machine and would be cost effective to overspeed slightly and install a DIY CNC.
Just stay close to the context of it's originally designed intent.

[Oldmanandhistoy]

DareBee,

No harsh tone noticed here I'm learning the spend now to save later (could have been considering an X4+ ). I don't want to spend in haste and it's difficult to find a small home workshop size machine for aluminium.

I would be happy to pay extra for more rpms and a one shot oiling system and still looking.

Thanks again,
John

[handlewanker]

Hi John, failing a Bridgeport, I think option #2 is also a fair choice, just depends what you want to use it for overall.

I notice that it doesn't have any feed mechanisms to the various X-Y axis, so you would probably be standing there hand feeding it, No problem?

I recently (two weeks ago), fitted a power feed mechanism to the X axis on a Bridgeport mill I once owned, but sold to a mate of mine, and he wanted to be able to have a feed mechanism and quick traverse.

The feed mechanism is the type that replaces the right hand end handle bracket and supplies power to the X axis, costs about A$750, (about 380 quid),works a treat.

Also, I personally prefer the R8 collet setup of the Bridgeport, although at the moment I have an Ajax knee mill, like the Bridgeport, but 1-1/2 bigger, and that has ISO 40 taper in the head, which means a bit more expense for all tool holding options, but do I like the ER32 collet chuck I bought for it.

I really miss the Bridgeport, but my mate, who's still working for a living, needed it more, whilst I'm retired now and only do various hobby work to amuse myself.

If you aren't strapped for cash, I'd have a look at the Deckel mill range, not sure of the model number, but they have some pretty decent tooling applications built into them.
Ian.

[Oldmanandhistoy]

Hi Ian,
Thanks for the advice but I have rejected all the above choices and got myself a nice Harrison with the vertical head http://www.lathes.co.uk/harrisonmiller/index.html . I’ve replaced the motor with a 2800 rpm single phase motor, 3hp which gives me about 3600 rpm max on the vertical head (after replacing the gears for the higher speed range).
I couldn’t cope with the idea of another Chinese heap of cr*p and do not have room for a BP. I’m power feeding all of the axes with stepper motors which gives me accurate (enough for intended use) positioning and allows PC control as and when I need it.

You just can’t beat old iron imho

John

[handlewanker]

Hi John, Pity about the BP, once a BP owner always a BP wanter.

I found the turret head with multi angle ability on the head to be so verasatile I wouldn't consider any other method practical.

I worked a TOS universal mill in my early days and it had the vertical head like the Harrison in your link, but I found the weight of the knee to be too heavy for most tool making work, and although it had feeds and fast traverses in all directions, the verasatility of the quill and R8 collet system on the BP was a most deciding factor in my choice of "must have" features.
Ian.