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View Full Version : Selection of milling machine to complete model steam engine.



Brownie
10-22-2012, 05:57 AM
I have settled on a Grizzly GO619 mill drill to complete my current steam engine and other projects of the same nature. Does this machine have acceptable rigidity and accuracy to complete projects of this nature? I currently have a small metal shaper, lathe, drill press and related machinist tools from my apprentice days many, many years ago.

Brownie

oldtiffie
10-22-2012, 06:23 AM
That machine is a Sieg SX3.

I have one and am very pleased with it as it does all I ask - small jobs and small cuts with no "tear-ar$ing".

I don't make "small engines" but I like what I've seen of them here and from what I can see the SX3 will do very well as it is very accurate and robust for its size.

SGW
10-22-2012, 06:27 AM
It depends on the size of the model you are making and possibly how ingenious and patient you are. As long as you stay within its capabilities it should do well.

Brownie
10-23-2012, 10:53 PM
Thanks for your reply. I am trying to locate a dealer in central Indiana who carries this machine. I am reluctant to order without "touching" the machine.

Brownie

flylo
10-23-2012, 11:03 PM
Brownie, if you don't find a dealer I'm almost sure someone has one near you. Maybe thru a forum or user group on model making or small shop machining you can find an owner close by that would show his to you. Just an idea.

Forrest Addy
10-24-2012, 12:50 AM
Careful there. This machine has no mechanical speed changes (gears, step pulley, V/S belt etc). The sole methodd of altering spindle speed is electronic variable speed.

Electric motors are pretty mch conctant torque devices. The machine might be rated 1 HP at max spindle speed but the HP at the spindle will change in rough proportion to RPM with the speed control setting. It will run a 1/2 endmill just fine but if you wish to take a facing cut with a 4" dia flycutter the machine may not have enough oomph at the tool to take any but the lightest cuts.

If you can accept this limitation fine, but if you wish to run larger cutter diameters you may wish to find a machine having three or more steps of mechanical speed reduction.

Will power feeds be important to you? I notice there is no power down feed on the quill making smooth clean bores with a boring head a little tricky.

Don't get me wrong. The Grizzly G0619 is probably very suitable for model engines, horology, and other small scale machining projects. It may be less desirable if you decide to branch into larger scale work where significant volumes of metal have to be removed. The spindle speed limitation may work against you and make stock removal slow and tedious.

You may wish to take a step back and look at your future projects for a clearer idea of the machine features you may require. If the machine you're looking at still suits you, go for it.

Shop carefully

oldtiffie
10-24-2012, 01:39 AM
I can hand-feed for boring using either the quill or the vertical dove-tail - dove-tail is preferred as it eliminates what ever clearance there is on the quill (which I lock during boring).

The motor control and torqe are really adequate - you may be surprised.

There is a quite good (but a but "heavy") optional power feed which is not bad.

Mine has an MT3 spindle taper and all my adaptors are MT3.

Spindle cutter diameter is limited to (I think) 2 1/2" > 2" preferred - which it handles very well.

http://www.machineryhouse.com.au/M515

http://www.machineryhouse.com.au/M516

If you want to "get bigger" hang on to the SX3 as it works very well as an auxilliary machine.

Mcgyver
10-24-2012, 08:53 AM
The motor control and torqe are really adequate - you may be surprised.

.

maybe. pics please :D

uncle pete
10-24-2012, 02:46 PM
Brownie,
I totally agree with the others. One way or another you are going to run into a torque limit. It's electrically impossible not to with a variable speed system like that mill has. I certainly don't think you'd expect to be drilling 1 1/2" holes thru 304 stainless. Where you would need that bottom end low speeds would be with oversize flycutters, boring heads, etc while skimming or boring parts or castings. And if you can swing the extra price, I'd highly recommend that add on power feed also. Spinning that handwheel would get real old real fast. It's got a R-8 taper so that's a real bonus. If it's not made in R-8 you probably don't need it.

And a few pointers if you don't mind? NONE of these mills are properly cleaned or assembled to what can be expected from the much higher cost industrial level equipment. You will want to pull the table and Y axis assembly apart before you use it. And on that mill, I'd also pull the Z axis gearing and feed screw. All that dragon fat preservative grease is just that. It's not the proper way lube. When I did my Taiwan built mill, I certainly didn't find pounds of contamination. But there was more than enough cast iron and some grinding dust that it was well worth doing. It's not a complicated job, it just takes some time, solvent, a few cheap paint brushes, and some paper towels or clean rags. And replacing that grease with the proper way oil will allow it to operate much smoother and be adjusted much tighter while still allowing smooth travels.

And you are going to need to tram that mill in before using it. These dovetailed rear column types are a bit more complicated to do than something like a bridgeport since you need to shim or scrape the rear column in both X and Y axis's so it's actually correct, and then tram the head and spindle to the table. There's lots of good informative threads around on various forums about how to do it. Super accuracy mostly isn't needed for what your doing, but drilling the steam passages in the cylinder and drilling, boring, reaming any cylinders or linkages so there's no binding would be where you want your mill set up so it's as close to zero as you can get. That's just common sense, and again it's worth doing.

You may find an issue with that rear hollow column and it flexing when using a boring head or even while using larger drills. There's some good threads over on the CNC Zone forum about adding some concrete Viagra. But overall I think that mill will work pretty well for what you want it to do. It's certainly light years ahead of the X2 types, and there's been more than a bit of impressive work produced with those.

Pete

Forrest Addy
10-24-2012, 03:12 PM
I just had a look at the G0619 PDF manual on the Grizzly website. It looks like there's lots of room in that sheet matal belt guard. I bet a clever guy could stuff in a 3 step pulley to get greater transmitted power at low RPM.

Ratio selection might be a stumbling block. I suggest the top ratio the same as stock. The second half and the third quarter speed respectively but a second reduction may be needed for quarter speed. PITA to change belts but if you can take a decent cut with a fly cutter in steel....

Anyone got one of these? Maybe take a look for practicality and get back to us?

uncle pete
10-24-2012, 04:54 PM
Hey Forrest,
Great idea, it's been done numerous times. Too many to really list. I just Googled "X3 belt drive mod" and a whole bunch came up.

Pete

oldtiffie
10-25-2012, 01:10 AM
Just how many of the posters have seen let alone used a Sieg SX3?

oldtiffie
10-25-2012, 01:41 AM
I have settled on a Grizzly GO619 mill drill to complete my current steam engine and other projects of the same nature. Does this machine have acceptable rigidity and accuracy to complete projects of this nature? I currently have a small metal shaper, lathe, drill press and related machinist tools from my apprentice days many, many years ago.

Brownie



Thanks for your reply. I am trying to locate a dealer in central Indiana who carries this machine. I am reluctant to order without "touching" the machine.

Brownie

I think the OP just wants experienced advice from users of that Sieg machine.

BigJohnT
10-25-2012, 08:11 AM
Griz has three showrooms, the Springfield one is 3 hours from me and I've been there several times. I don't know if they sell via dealers. I'm like you I want to put my hands on something like that to make sure it fits my needs and the quality is good enough before I put out the cash.

Interesting that an Amazon search for Sieg Sieg SX3 (http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Sieg+SX3) turns up the Griz model by a couple of different sellers who turn out to be Grizzly.

John

Brownie
10-25-2012, 10:25 PM
Thanks to all of you for your helpful comments. I did send an E mail to Grizzly 'yesterday and they gave me the name of an owner in northern Indiana. I have not contacted the gentleman yet but will do so in the the next few days. I will give feedback after I talk to him.

Again thanks!

Brownie

macona
10-25-2012, 11:07 PM
Careful there. This machine has no mechanical speed changes (gears, step pulley, V/S belt etc). The sole methodd of altering spindle speed is electronic variable speed.


This mill has a Brushless DC spindle motor. It is quite a different beast than a motor with a VFD or a DC brushed motor with a SCR or PWM control. The brushless motor has feedback to the control via encoder or hall effect sensors and is mostly a closed loop system so you have for or at least a significant portion of full torque at all speeds.

oldtiffie
10-26-2012, 01:58 AM
Thanks Macona.

That agrees with my experience as at lowest speed (90 rpm) I can grip the spindle as hard as I like and there is no sign of straining or stalling.

Same when cutting - set a speed it gets there quickly and in a cut it may drop a rev or so but it soon picks up to the set speed while cutting.

Tapping 3/8 in steel, brass or cast-iron goes very well - it has a ("tapping") spindle reversing switch right under your thumb on the spindle hand feed handles (3).

I was amazed at just how good (within limits) a small bench-top (no floor "foot-print") could be.

I can't say how it would go with the OP's model-making as I have no experience there but I can say with the smallish work I do it does it very well.

macona
10-26-2012, 02:20 AM
On the tapping, does the motor run in reverse (CCW) until you press the button?

oldtiffie
10-26-2012, 02:29 AM
Yep - alternating forward and reverse - 3/8 capacity.

See specs:
http://www.machineryhouse.com.au/M155