Sieg s3 gib twist.

[ian_in_the_midlands]

Hello.
I have recently purchased a new Sieg s3 lathe, and am disappointed with it. Both gibs are twisting as I tighten them.
Even if I set them, they shift after the lightest cut and rigidity is then lost,
The compound slide is the worst.
I have replaced the adjustment screws with cone point, but this has not helped.

From looking on the internet, this appears to be a common problem.
Fixes seem to be :
1. Make better gibs that fill the hole better.
2. Drill holes for additional adjusters lower down.
3. Pin with dowels.

My concerns are:
1. I have no mill. I would have to make new gibs using a file. Is this practical? (I have limited experience of working with metal).
2. Does this fix work? The new holes would have to be very close to the edge. Is it a fix that works, and worth risking ruining the compound slide?
3. Probably beyond my ability.


Has anyone got any details and pictures of these fixes?
Are any other fixes that I should consider?
Thanks.

 

[bazmak]

Hi i made new full size gibbs in brass quickly and easily without a mill
fitted additional adjusting screws and covered all points you mentioned
You can check out Bazmaks thread.I used a cheap belt linisher set up as described to 30o with a holding fixture.I ground them down quickly and accurately to 2 thou with excerlent finish and didnt even have to bed them in
The cheap belt/disc linisher cost me $70 and once modified with a simple more robust table gets lots of use.Worth its weight in gold.If you are able to buy one
i will run a thread on mods etc for you.Regards Barry

 

[bazmak]

Hi the thread is under Bazmak diary of a sieg 7x16 mini lathe
towards the end with photos.I originally had to make a replacement
gibb in brass for one missing from the Advance lathe and came up
with the idea.It worked so well that i then made new ones for the
the sieg.Keep in touch regards Barry

 

[bazmak]

Hi again if your in UK midlands you can get the Linisher at Machinery Mart
under Clark Brand.Cheap and Nasty but can modified to a good standard
The free roller has plastic bushes which didnt last long i bored out and fitted cheap skate bearings,but i have had mine with good use for many years now

 

[oldboy]

Hi Barry.

I would be very interested in your mods to the linisher as I am sure others would be, so would be very grateful if you coul write them up. Loved your write up on your 7 x 16 some of your mods are great. I am also going up to Tuggerah to have a look at the Titan mill which you have sometime in the next week or so.

Love your work.

Barry

 

[bazmak]

Hi Oldboy,you wont be disapointed with the Mill,will take some photos of the linisher and do a short writeup.Just simple things really but easily done
and makes a cheap machine really useful.Regards barry

 

[ian_in_the_midlands]

That is a very interesting thread Barry. I had read it before. Does the full sized gib work well?
I notice you had not drilled for additional adjusters. Did you not find these necessary?
Also, I have some concerns about using brass. I have read peoples concerns regarding the softer metal will pick up abrasive and working like a lap.
Should I be concerned about this?

I ordered some flat steel a few days ago off Ebay to attempt making some gibs.
I will order some brass too.

Just to show how little I know, am I right in thinking the gib should contact at faces A and B, with minimal clearance at C and D?
There should be no contact at E and the carriage should ride on face F?

 

[ian_in_the_midlands]

Reading the thread again, but this time more carefully, I see you have fitted additional adjusters. Did you find you had to mount these lower or are they in line with existing? If lower, how close did you go? I was thinking of adding M3 adjusters as the smaller diameter would allow me to move closer to the edge.

Have you any pictures of drilling the holes?

As a test this afternoon I laid a 0.022" shim on top of the gib (at point B). This has reduced the twist considerably, and the gib appears to be sitting at a better angle now. Faces at F are still in contact. Unfortunately with the adjustment tight, it still does not take much effort to lift the slide so that the faces at F open.
This does offer me some encouragement that a new gib and additional adjusters may resolve my problems.

 

[bazmak]

Hi Ian,i will post a thread and sketches shortly and try give my opinion on your
concerns Regards barry

 

[bazmak]

Back again.I first measured the dovetail in the cross slide with the gib removed
It was 6.5h and 6.2 w. The existing gig measured 5.6 x 5.6 Plenty of slop
I used a piece 1/4" brass 6.35mm and decided to make it 6.1 w
I dont have cad so drew it out 10x fullsize as sketch this gave me a reqired width of brass at 10.85.I hacksawed a piece just over 11 wide and 5mm longer
than the cross slide.I drilled 2 holes 3dia on cl.Using a piece of 40x5 flat i drill and tapped 2 holes M3 and bolted the gib to it with the good edge to the top
As per previous thread i linished the brass (and the steel bar) to a knife edge
I then reversed the brass and linished the 2nd edge to the 6.1 dim and using the check dim of 12.6mm.I put a small radius on the 2 diamond corners and it was a good fit in the cross slide.I then blued took off the high spots and fitted to the cross slide.The natural tendency is for the screws to rock the gibb and bear on two corners.It still did but much reduced.I the spotted thru
the slide and dimpled the gib. Fitted 2 additional screw in line. M4 i remember

 

[bazmak]

Do you intend to linish or mill ? In answer to your questions
I think brass is better than iron .A is the main brg face,B&C are part brg
as the gibb twists and rides on 2 apposing corners F is bearing and E,D are clear
When you have it assembled without the leadscrew,lightly nip up the screws and
work back and forward or blue and check the high spots as long as you have a decent brg area i would accept it as removing the high spots just allows it to rock more.I think you will be more than happy Regards Barry

 

[ian_in_the_midlands]

Thanks for advice. For my first attempt this week I intend to ...... File it by hand.
I plan to make a wooden holder/guide and check progress regularly.
Maybe unpractical, but I don't know until I have tried.

If this does not work I do have a belt sander, but I really want to keep this for wood, not metal.

 

[ian_in_the_midlands]

Thanks for all advice.
I went with brass as no horror stories about lathe wear.
Initial results feel good. Twist appears to be eliminated.
I will give that lathe some use and see how they bed in.
Thanks again for the help.

 

[bazmak]

Hi Ian,how did the dims i gave you from the sc2 compare to your sc3 ?
How did you hold the piece to do the second side and how long to do the filing
Regards Barry

 

[ian_in_the_midlands]

I made the gib to fit rather than make it to your measurements.
Although I was consistently measuring whilst making it to ensure a constant width, I can't remember what the measurements were now. Sorry.
I made a wooden holder by routing out a 1/4" slot and planing a bevel to match the slide for my filing. I then scribed a line to aim for that would give me the desired angle.
I found I was having trouble gripping the holder in my vice so I resorted to the belt sander.
For the second side I simply reversed the strip in the holder.
I then had to lap the side closest to the adjuster screws to get the required thickness using a sheet of wet and dry stuck on a sheet of glass.

The point where the cone point of the grub screws contact was found by simply screwing them in to make a mark.
I then centre-punched the mark to give them a hole to sit in.
I may file these points flat in the future if need be.