help/advice with the sieg sx2 benchmill

[bazmak]

I am not happy with the fine downfeed on the Z axis.A lot of backlash and the head has an annoying habit of dropping a couple of mm at the wrong time
Before i strip it down can anybody offer advice on adjustment etc.I dont want to spend too much downtime as i would rather be using it.I assume most of the problem is the rack and pinion ???.Thanks in advance Regards barry

 

[kf2qd]

The vertical slide lock is in a nice position to just bump with you finger and provide some drag so the spindle can not come down on its own. Even works if the balance spring is disconnected to allow just a bit more travel.

 

[Tin Falcon]

I am not happy with the fine downfeed on the Z axis.A lot of backlash and the head has an annoying habit of dropping a couple of mm at the wrong time
Before i strip it down can anybody offer advice on adjustment etc.I dont want to spend too much downtime as i would rather be using it.I assume most of the problem is the rack and pinion .Thanks in advance Regards barry

I never trusted the fine downfeed on mine the micrometer lines are useless.
But easy work around I just put a dial indicator on it just a mag base on the column . then just read the diail . I always keep the lock on unless i was moving it. I found just unlocking the lock and re-locking would move the head down 3-5 thousands so usual would just play with the lock for a fine cut. Primitive but it works. Digital indicator from harbor freigh make a cheap z axis dro.
Tin

 

[velocette]

Hi Bazmak
The spring and quadrant are not strong enough to hold up the head properly. An air spring kit is a vast improvement on the original setup.
It should support the head completely with the tendency to raise the head with the lock loosened.
See
http://www.littlemachineshop.com/products/product_view.php?ProductID=2258&category=879658189

Eric

 

[jayville]

I fitted a gas strut to side of my mill and solved a lot of problems ..no more head drop and makes drilling a lot easier..I also have a vertical dro fitted on find feed side of mill..I find that once I have selected my depth of cut and set the column stop it still drops down maybe 0.02 or so I have learnt to allow for this when I set up..I haven't had many problems since I installed the gas strut..quite good actually. Clem in tassie

 

[purpleknif]

I put a counterweight on my XJ 9512. Worked wonders.

 

[rythmnbls]

I put a counterweight on my XJ 9512. Worked wonders.

+1, I went with a counter weight, properly adjusted gibs and dial indicator. The z-axis dial on my X2 was .060" per turn and had about a whole turn of backlash, making the dial useless for measurement.

Regards,

Steve.

 

[bazmak]

Thanks for the replies.I have in the past read the improvements with gas struts etc.I have also found the downfeed dial primitive and the lock must be tight
before using.I want to keep downtime to a minimum and reduce vertical
backlash.My question is this.Can an improvement be made to the rack and pinion mesh where i assume the main problem lies,ie by shimming the rack
etc.I may also look at improving the lock and making a new dial etc
Just trying to get some input before stripping down

 

[velocette]

Hi Barry
Most of the backlash is in the coupling the dog clutch and the poor mesh of the worm and wheel.
You can replace the coupling with a solid shaft extension on the worm shaft it helps a little also shimming the rack to a minimum backlash will help.
A larger diameter wheel is a huge help for control.
Short of fabricating a new worm and wheel and dog clutch or a friction clutch that can be pulled up tight and locked.
A digital readout is probably a better option.

Attached a pic of Hand Wheel and shaft

Eric

 

[bazmak]

Might try that velocette thanks.Just stripped down and redid the gibbs for the X and Y.Tried shimming the rack and retensioned the spring arm.No good so just tightened iu the gibb on the Z axis.Also want to change nthe hwheel on the
x axis larger for more leverage etc.Dont want to get too involved would
rather be using it.Will keep posted

 

[bazmak]

Good idea from velocette.Removed the cover and and universal joint linkage
Made a new drive shaft.It has taken out all the play and added just the right amount of tension.I made a new 3" dia alum. wheel and press fit over the existing.Works really well.I tightened up the gibb strip to give me the right tension and take the free movement out.Big improvement.Time will tell

 

[kiwi2]

Hi Bazmak,
What is your current opinion of the X2? I'm going to replace my Emco V10P lathe/mill combo with separate machines early next year so I'm looking at mills and lathes now. I want a machine which will work well out of the box without having to modify it to make it work properly.
Regards,
Alan C.

 

[bazmak]

Hi Kiwi,very happy with the SC4 lathe,as i was with the SC3.The 4 is twice the price and weight of the 2 but nothing to do,works straight out of the box
Very happy with the mill,but must have R8 spindle and fixed column
but for 25% more you could try the X2.7.Looks very good on paper

 

[kiwi2]

Thanks Bazmak. Do you know where to find detailed specs for the Sieg gear? The info I can find on their website is very basic. I want to know things like the distance between the mounting bolts and the system for fixing the chucks to the headstock so I can decide whether to keep some of my existing gear.

Regards,
Alan C.

 

[chucketn]

Alan, Try e-mailing Chris at LMS and ask him if there is a drawing of the C4 spindle available. They have drawings of the C2/C3 lathes and both MT2 and R8 spindles of the X2 mill, as I have collected them.

Chuck

 

[bazmak]

Hi Kiwi,it depends where you are in the world,therefore your supplier
I got mine from aussie machine tools in melbourne they have a website
and will post a nice brochure.If you give me an idea what you are looking at
i can give you any info you need regards barry

 

[kiwi2]

Thanks for the suggestions. I think I've figured out the chuck mount on the SC4 lathe. My current ER 25 collet holder is only 78mm OD with a 41mm recess so I'll either have to make an adaptor - as you did Bazmak - or splash out US$17 for an MT3 holder from CTC Tools. This is the same as the cost of an R8 holder I'll need if I get the new mill.
I got a hold of the local agents and they sent me a pdf catalogue. There's still not a lot of detail in it. I'm tempted to go for an SC6 lathe which is closer in size to my current lathe but it will only do 12 metric threads as opposed to the 17 metric threads the SC4 will do.
The lathe will have to come in on a 90 day back order which is not necessarily a bad thing. My shed is at the back of my house across the lawn which is too wet at the moment to drive over. If it ever stops raining here, it should be rock hard in another three months.
Thanks again for your help,
Alan C.

 

[bazmak]

You dont say where you are from.I would recommend the SC4 over the 6
Adaptor plates are easy for the sieg lathes but i bought my last one for the SC4
well worth the $20.As for the Mill i paid $1000 for the sx2 with R8 and fixed column but for $300 extra you can get the Sx2.7 It looks good. Both machines make ideal companions at about 100kg each Regards barry

 

[kiwi2]

Hi Barry,
I'm from New Zealand.
I'll probably go for the SX2.7 or an SX3.
Although I can see the advantage of a speed contolled motor on a lathe, what is the advantage of a speed controlled motor versus a fixed speed motor with manual gear reductions on a mill?
I seem to remember a thread from a couple of years ago which recommended replacing the geared connection to the motor with a belt but I can't find it. I think the problem was that the plastic gears were too easily broken. From what I can remember there was a kit available to do the conversion. How is the motor on the SX2 connected?
Why do you prefer the SC4 to the SC6 or SC8?
The catalogue says you can cut 17 metric threads or 10 TPI threads on an SC4. Is that on the same machine or is it 17 metric threads on a metric machine or 10TPI threads on an imperial machine?
Regards,
Alan

 

[bazmak]

Sx2.7 is the latest design,the sx3 is much heavier it depends what you want
it has 750w high torque motor with belt drive variable speed.Works really well
very quiet and being able to vary speed at the touch of a button is good
Geared head models are old hat and too noisy
The sc4 and sx2.7 are 100kg each.The sc6 and sx3 are over 100kg each
depends on what you want and how much you want to spend
Personally i would go for the sc4 and sx2.7.Any further questions please ask
Regards barry