Author Topic: Newb mill questions  (Read 10459 times)

Offline Trion

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Newb mill questions
« on: January 15, 2010, 05:56:16 AM »
Hi guys. Again, I've found a nice mill that I'm considering to buy. It's a SAJO UF 52 DM.

Facts:
Table size 1250x290 mm.
Spindle movement X-850 mm, Y-210 mm, Z-465 mm
Spindle taper: ISO40 horizontal and vertical
Spinder speed horizontal: 40-1800 rpm (12 steps)
Spindle speed vertical: 110-1850rpm (8 steps)
Available feeds (X/Y) 20-765 mm/min. (12 steps)
Available feeds (Z): 10-382 mm/min.
Additions: Coolant system, one vertical head with quill, one vertical head with two angle adjusments

Special features: The horizontal spindle is driven by a 5hp motor on its own 12 speed gearbox. The vertical spindle is driven by a separate 5hp motor with a 8 speed gearbox. The vertical spindle motor is mounted in the "boom" (the upper part which the bearing blocks for the horizontal spindle are mounted on) making it possible to position the vertical milling head in the Y direction as one pleases.

Downsides: The shaft and one of two bearing blocks for horizontal milling are missing.


Questions:
- Will the 8 speed options on the vertical spindle be a limiting factor?
- Other things I should look out for?

Offline Darren

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Re: Newb mill questions
« Reply #1 on: January 15, 2010, 07:57:14 AM »
If it were for me I'd consider the spindle speeds to be a limiting factor at both ends.

In vertical 110 is a bit fast for larger flycutting esp with some tougher steels and 1800 is a bit slow for small dia cutters.

My mill has 3,000 rpm and that is slow for smaller dia cutters, esp say 3mm as they snap far too easily. I believe running them faster helps in this regard? 4mm I can get away with, just ...

For horizontal you need the missing bits or it will prob be unstable.

It would have to be cheap...

Just my thoughts ...  :coffee:
« Last Edit: January 15, 2010, 10:50:10 AM by Darren »
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Offline kvom

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Re: Newb mill questions
« Reply #2 on: January 15, 2010, 08:19:59 AM »
5HP is pretty strong compared to normal hobby mills, so you can take big cuts.  But as Darren says, the speeds are a little low for small cutters.

Offline Bernd

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Re: Newb mill questions
« Reply #3 on: January 15, 2010, 10:29:08 AM »
Trion,

I guess I need to ask the question, what do you plan on making? I'm begining to think you are going to mill large pieces by the interest in the machines you've ask about so far.

Bernd
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Offline Darren

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Re: Newb mill questions
« Reply #4 on: January 15, 2010, 10:50:51 AM »
Yes that seems more like a hogging machine than a fine precision tool ...
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Offline Trion

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Re: Newb mill questions
« Reply #5 on: January 15, 2010, 10:55:26 AM »
Thanks for the quick reply guys :thumbup:

Darren: I hate to go against experienced peoples good advice! Makes me feel twice as dumb, when I eventually discover they were right in the first place! :hammer:
Until now, I had not found any disadvantages, except for the missing horizontal milling parts. But, I dont plan on using this in the nearest future anyways.
Regarding the speed, some say it's going to be ok. Since I'm a hobbyist I'll just find the speed that looks to be working ok for the current application and not think about it any further. But then there are the more thorough ones, like you, who reccomend a wider speed range for more optimal cutting conditions. I like to listen more to the ones who actually refer to their own experience, but I also have to take the costs into account. For a similar amount of money, I'd get a new mini mill about the size of an X3.

Asking price is about £1000, that is quite cheap compared to prices for the same machine in Sweden, where it was made. When googling the name of the mill, one can find several companies that have added exactly the same mill, or it's bigger brother, to their machine stock during the last years.

When you say a larger fly cutter, can you estimate what diameter? I assume you are talking about a HSS cutter? Just want to know if it's something I'm likely to be using.


kvom: considering it costs about the same as a new sieg X2/X3 over here, it sure is a lot of machine for the money. And I'm not sure I'll need to use smaller than say 5mm cutters in the nearest future. :scratch:


Bernd: I plan to use the mill to make the occasional tooling for itself and the lathe. Apart from that I want to make flanges, surface manifolds, heads and blocks for cars, and some day I'll take on boring an engine block. Until now, I'm still to fascinated about making stuff for things that I can ride in, but when I discover model building I'll have to make some changes to get higher speeds.
When I get some experience on both machines, making a high speed head for the mill would make a nice little project! I'm thinking a motor mounted on the head in parallell with the spindle, belt-pulley transmission and no quill. :dremel:


I also spoke to the seller today, and got some additional information. Axis movement in all directions has been tested, runs quite light when turning the handles manually. Both spindles run smoothely, tested in several gears. Even the coolant pump works, despite it having not been used for the last years. The quill extends about 50mm and has a handle for quick drilling and a small turning wheel for precise cuts.
There are two central lubrication systems, as I understood, one is on the table and has a little handle to pump it. Transmission oil levels are all above the lowest mark, but have not been changed for the last 3-4 years. The machine has not been used more than possibly 5 hours in the same period, as it is owned by a hobbyist who restores old american cars.

Offline Darren

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Re: Newb mill questions
« Reply #6 on: January 15, 2010, 11:03:37 AM »
I'm thinking of fly cutting car cylinder heads, just about to do my first one this weekend so I'll let you know how I get on and what speeds I used.

Tables can be light just by slackening the gib screws, it means nothing and could still be worn.

As a hobbyist you want more range, not less. A production shop would be happy with a limited machine IF they had a job for it in mind.

£1000 is way too much, here I'd be looking at £250-400 max for that machine. Esp as parts are missing. In fact it might not even sell here at all and end up as scrap. I'm not saying it's only scrap by any means. It's prob a good machine, but buyers should be able to find better for less money.

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Offline Bernd

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Re: Newb mill questions
« Reply #7 on: January 15, 2010, 11:21:40 AM »
Bernd: I plan to use the mill to make the occasional tooling for itself and the lathe. Apart from that I want to make flanges, surface manifolds, heads and blocks for cars, and some day I'll take on boring an engine block. Until now, I'm still to fascinated about making stuff for things that I can ride in, but when I discover model building I'll have to make some changes to get higher speeds.
When I get some experience on both machines, making a high speed head for the mill would make a nice little project! I'm thinking a motor mounted on the head in parallell with the spindle, belt-pulley transmission and no quill. :dremel:



Now that we've established what you want to do I would say the type of machine your looking for is exactly what you are showing us. The machine needs to be fit to the job you are going to do. As far as how much money your going to pay for such a machine you would need to look at the market in your area. I'm going to assume that second hand machines in you country probably isn't plentiful. Darren says the price is way to high. I'm looking at it as US dollars. If somebody offered me that machine for $1,000 US dollars I would buy it. After all I paid $3500 for my Bridgeport last year. That might seem high for some, but it was what I wanted and it was all there, including a two axis DRO.

Now when you get to building models then I would start looking for a bench top mill and/or lathe. But for right now for what you want to do I would say you're on the right track.

I was always asked what kind of computer a person should buy. My question always was "What are you going to use it for?" Are you going to play games, do cad work, sort large volumes of data. That is what should determine the type of machine you will need.

That is my thinking on this. Fit the machine to the job you want to do. You already know what you want to do, now it's just a matter of finding the right machine. You are on the right track as far as I'm concerned. I'm also thinking this machine might be something to consider buying.

Bernd
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Offline Darren

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Re: Newb mill questions
« Reply #8 on: January 15, 2010, 11:29:40 AM »
I need to ask one question, what size cylinders and blocks do you have in mind?

If 4 cylinder you need to make sure the x travel is as long as the block and twice the dia of the cutter.

You could loose 16" of travel in the cutter itself. Then add the longest head/block you might work with.

First person to ask me why 16" gets the booby prize  :lol:
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Offline Darren

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Offline Trion

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Re: Newb mill questions
« Reply #10 on: January 15, 2010, 11:48:44 AM »
Darren: The owner has surfaced some cylinder heads with a large 22-insert carbide surfacer where he removed all cutters except for one. He used 500rpm and a feed some steps above the lowest. Guess the info is quite useless without the cutter diameter though :doh:

Well, he claimed they ways weren't worn. I don't have the ability to see the machine before I buy it, so I'll have to trust him on that.

So I should look for a machine with a bigger speed range. I see your point, but after having had a daily look after machines for sale the last year I have yet to see any other machines than this humongous type machine or new mini chinese ones. This is actually one of the smallest so far!

It seems there is quite the difference between the norwegian and english machine market. For £250 you'd get a set of chinese parallells, or maybe a small vice. Those are all things that I can buy from UK or USA, but when you're talking about a 1tonne machine it gets more difficult. ::)
Price wise, older and worse looking Sajo machines start at £1800 and if they look good and have DRO the may cost up to £6000! :poke: Some say I'm guaranteed to sell it for the same price if I decide I don't like it..

Bernd: I'm sorry that I didn't say that in the first place. Nice to finally hear someone support my choice, most people seem to be teaming up with my girlfriend who probably is making an evil plot to stop this as we speak :borg:
Price wise it's 1760$ at the days currency. What you paid for the bridgeport would be cheap considering the DRO.

I was very fascinated by bogs way of making parts interchangable between the lathe and the mill. Amongst others, I'd like to make a rotary table which has the same quick change chuck mount as the lathe. Ofcourse this would increase the heigth of the table quite a bit, but with almost half a meter of travel, that shouldn't become a problem :)
« Last Edit: January 15, 2010, 01:08:29 PM by Trion »

Offline Darren

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Re: Newb mill questions
« Reply #11 on: January 15, 2010, 11:53:00 AM »
Please don't be thinking I'm trying to put you off, far from it.

It looks a very capable machine, at 5hp it sounds quite a monster. I'm only trying to give you some things to consider, nothing more.  :thumbup:
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Offline Trion

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Re: Newb mill questions
« Reply #12 on: January 15, 2010, 12:20:50 PM »
Darren: Cylinders are stock 86mm. Stroke is also 86mm, but to bore to the bottom of the sleeve i guess i would require up to max 150mm movement. It has some 460mm z-axis movement. I was thinking of using a regular boring head. The block is 300mm high, then there is 165mm left for the length of the tool. It should go, if I haven't overlooked something.

The X-axis movement is 850mm, the block is maybe 450mm. A 16" surfacing tool should make things interresting :lol:

Thanks for finding the links! Damn those mills were cheap. Aspecially the Elliot, with DRO, vice and tooling. But the price would probably be doubled before it got here..


I appreciate that all of you are taking time to look at this! You have definetely succeded in giving me things to consider! :nrocks:

Offline Trion

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Re: Newb mill questions
« Reply #13 on: January 15, 2010, 12:55:55 PM »
Having seen  :worthless:  in almost every post, i thought I'd please you with some pictures :)


Offline Bernd

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Re: Newb mill questions
« Reply #14 on: January 15, 2010, 03:17:43 PM »
Bernd: I'm sorry that I didn't say that in the first place.

I noticed nobody was asking what you were going to do with such a large mill. Since a majority of the members are into model engineering they assume you are too. They never think of asking what you want to make/do with such a large machine. Now that we know we can better help you make an informed choice.

You stated that you would like to bore the engine block cylinders. If I were going to do something like boring I'd want a machine that has either a feed on the spindle, such as a Bridgeport or the knee of the mill can by used to feed the table up. Remember you can't feed manually consistantly. You definatly want some sort of automatic feed rate.

Bernd
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Offline Darren

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Re: Newb mill questions
« Reply #15 on: January 15, 2010, 07:39:49 PM »
As it has feeds on all axis then it should be fine for boring  :thumbup:

Looks like a nice solid machine in the pic's
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Offline Trion

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Re: Newb mill questions
« Reply #16 on: January 17, 2010, 04:36:28 PM »
Well, how shall I put this.. I bought it :D :D

Hope to have it home within two weeks!

Offline Bernd

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Re: Newb mill questions
« Reply #17 on: January 17, 2010, 04:52:06 PM »
Hope it wasn't something I said that made you buy it?  :)

Great looking forward to seeing some pics of it coming home and being installed.  :poke:

Bernd
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Offline Harry Eales

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Re: Newb mill questions
« Reply #18 on: January 25, 2010, 09:30:30 AM »
Trion,
Since no one has brought this up, have you checked the electrics on this machine?  Most households operate on single phase power, whereas many large machines require 3 phase electrical supply. You can get a converter to change over from 3 phase to single phase but they cost about U/K £ 600.00.   :zap:      Ouch.

Harry

Offline Trion

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Re: Newb mill questions
« Reply #19 on: January 25, 2010, 10:16:45 AM »
The machine is 230V 3-phase, the same as my other equipment. I have that available in my workshop, but 230v 3-phase is outdated. Some day I will have to convert to 400V. I have checked, all the motors can be converted to 400V, but I'm not sure about the contactors and fuses. The machine has good electrical documentation, so the convertion should be straight forward. :dremel:

I know little of household/workshop electrics, but as far as I have understood, most new norwegian houses have 400V in the fuse box, but one only use one phase and therefore get 230V for the household stuff.