# Survey on Sieg 7" lathe - Bazmak



## bazmak (Dec 11, 2014)

Just posted on my thread on the sieg lathe concerning the slop between the carriage and the bed.The width of the bed will be fairly accurate and i hope the width of recess in the carriage,which has lots of play.With the saddle firmly located in the V i have a gap of approx 20 thou at the front and 60 thou at the back.If you put a horiz rotation force ACW and CW i have lots of play as the carriage tries to ride up the V.There is no location on the front and back edges
of the bed,
.I am currently playing about to try and improve this problem.So all you sieg lathe owners,please check and comment on this problem.Also please post the following dims and hopefully arrive at a remedy
1-Width of Bed.2- Width of recess in carriage.3-Gap at front and 4-gap at back.I have located the front gib plt to run against the rack,and hope to fit a 1/16" thick
gib plt and screws to the back,for location only.Hoping for lots of responce Regards Barry


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## goldstar31 (Dec 11, 2014)

The classic way- call it old fashioned- is to pull a new lathe to bits, cleans it  and adjust it -to one's own liking.

From then on, one regularly takes it to bits, cleans and adjusts it- to one's own liking. Sounds like the needle beeing caught in the groove- but that is engineering.

As far as a lot of lathes are concerned- of the cheaper variety they are put together in the shortest possible time and held together with the least possible adjustment. It is is cost accountancy so that you can afford them. If you can hold a wobbling gib with a couple of any old screws- so be it. If you have time- you read John Ruskin on Price.  Makes a change from standing on the edge of Friars Crag in the English Lake District and looking at the lake and alternating with  look at  his statue. It will not make your lathe better but you might realise that 'You are some man's lawful gain' 

Usually, there is nothing that is basically wrong with the bits that go together to make something that sort of looks the part- but doesn't.
You might find that someone in an effort to get a profit- which is why people work or whatever, has skimped the machining and left it there instead of scraping in- PROPERLY. You might find that there are two adjustiing screws on a bit of something that passes for a gib but in practice wobbles about like a pea on a drum. Perhaps it could do with putting a peg in the gib to hold it in place and perhaps a couple more adjusting screws. Agan, the gib might be far too thin and could do with a thicker one or the air space being filled with - well, some shim. Nothing more than having a coke and using a pair of scissors to make packing strips. You could even glue them together- with a pennyworth of two part epoxy.

It's often as simple as that. Remember that the factory never wants to see the lathe again but you do.

End of lecture. 

Norman


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## bazmak (Dec 11, 2014)

Nice lecture goldstar but all i want is feedback on the gaps to front and rear
of the bed.This will tell me A are all the lathes the same. B Has it caused a problem with anyone else C.Is anyone wanting to do anything about it.
Please will someone with this lathe post the requested measurements
Regards barry


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## bazmak (Dec 11, 2014)

Had to strip down the carriage to adjust the gibs so did the mod anyway.
Seems to have solved the problem.A piece of 1.5 thk brass 8 x 100 was a nice fit to the rear of the carriage and fitted 2 gibb screws.Set to just touch.
The front gibb plt was then pushed to just touch the rack.All locked up
 and the problem appears to have been solved .Only time will tell. Still hoping for input as 5 alive used to say Barry


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## Swifty (Dec 11, 2014)

Just be careful Barry, the back of the lathe is just a rough finish, the "V" has to do the location. If the back of the lathe is not spot on parallel to the "V", it might lift it up. Have you put an indicator trailing along the "V" as you wind the saddle along.

Paul.


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## bazmak (Dec 11, 2014)

Not done anything yet other than take out oodles of slop which was allowinthe carriage to ride up.Will see if i have any problems and check everything
when i test the the cross slide feed is square to the main axis.It was a couple of thou out as recall when i first checked out the lathe just after delivery
The rack may not be parallel either as its fixed to the bed casting.At this stage it seems to be an improvement.Regards Barry.


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## goldstar31 (Dec 12, 2014)

Lecture maybe- sorry Barry but the problem is endemic. The world is full of people who have bought these lathes and in the words of a cleverer guy than me 'Are asking the same silly questions and getting the same silly answers' This guy is building his own steam locomotive, a world authority on tugs and writes jazz for the saxophone. 

Quite simply, you go to Moran- Gadgetbuilder.com and the various fora. I've cross referenced and cross referenced - and am included in the same silly answer brigade. Most owners become disallusioned(sp?) and flog their lathes to another equally confused aspirant. 

The number of people that actually re-adjust their lathes etc seem to be counted on the amputated fingers on a fingerless hand.

I only commented because I like your style. It is like that.
Best regards


Norman


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## bazmak (Dec 12, 2014)

I can opnly say that i am very happy with the lathe and enjoy finding problems and sorting them out.This is a problem i have come across which i feel is an easy fix and wondered how many others out there know or dont know of it
Again i will reiterate love the lathe and the mill


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## /// (Dec 12, 2014)

Agree with you Baz. Enjoy my lathe immensely. 
Captain Jerry's quote in my signature also sums up my position pretty well too. 
The hollier than thou elitists can go jump.
I am planning to upgrade very soon, but it will be another Sieg as that is all my finances can allow.

Edit: Sieg, not site. Damned autocorrect!


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## goldstar31 (Dec 12, 2014)

As an elitist, I had a basket case of a lathe. It has been run on mahogany dust, it had stripped gears, it was worn out beyond getting spares- Myford had gone to the knacker's yard. It was awful and still looks it- but I doubt few  could afford it. 

As an old man, I pulled it down to pieces and had the bed professionally reground- to BETTER than original. The clapped out saddle is Turcited as is done to--- the better lathes. I handscraped every worn bit of slides and made and pegged gibs- better than original. The stripped gears were made on the mill drill - and there was a lot! 

It now has an inventory of accessories- bought or home made that is longer than when  the firm issued the catalogue. 

If an octogenarian I am now 84- can do this and who  was never an engineer- perhaps there is every reason to feel somewhat elitist. 

With failing strength and so on, I'm wanting to go CNC or something. Perhaps it will happen. Keeps me from being chased up the aisle by a raging father with a shotgun!

Cheers

N


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## bazmak (Dec 12, 2014)

There you go,the enjoyment is doing things you like whether it is refurbing a clapped out quality lathe or a cheap chinese.Hope your still doing it at 94 Barry


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## goldstar31 (Dec 13, 2014)

Thank you for your good wishes. Another thing- in case you missed it- I'm a grumpy old git.
I got a phone call prior to Christmas. Another grumpy old git. A Goldstar who was, like me, just a boy when we met up in 1949. Just 19, he was the best Spitfire mender EVER. The last of his Spits is still airworthy and now in Canada. We sort of owe our lives to each other. I'm still here- his other little Proctors with their worn out Gypsy engines always worked- when others did not! Life was cheap- but not to him!

I expect another Goldstar will drop a card in. He was the best man in my section then . He was only a telegraph boy on a motor bike before we met up in 1948. He never forgot that he weighed about 100 pounds then- he couldn't eat the swill we got. I got him another shilling a day to buy something edible.

It all taught one thing- to try to help each other. 

Enjoy your hobby but learn to accept funny old grumpy gits who have seen- well- a lot.

Norman


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## MCRIPPPer (Dec 14, 2014)

you dont need a gib on the back of the lathe ways like that. if the bottom gibs are adjusted snug the V will do the work of keeping you square. a common mod is to make new tapered gibs with tapered holders. it works wonders and will greatly increase your machining capacity  in the way of depth of cut and feed ability.


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## bazmak (Dec 14, 2014)

As you say you should not need a gib at the back.However there was play when the carriage was twisted as the it rode up the V.The gib was just touching at the front and back and has cured the problem.The reason for this thread is to get input from other owners of the same lathe and see if they have a problem


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## MCRIPPPer (Dec 14, 2014)

i own a 7x12 lathe and have done the tapered gib mod. after making new gibs you will not need the back gib and you will have no rotation of the carriage. you will be so glad once you do because it not only fixes the carriage rotation issue, but it makes the carriage more rigid in all directions. you will actually be able to bore holes to size and turn reasonable amounts of material off. i also put tapered roller bearings (trailer/ car wheel bearings) in the spindle which helped greatly with rigidity and surface finish. another good mod is to buy the littlemachineshop 16" bed upgrade, and use a milling machine to locate the holes for the rack and leadscrew blocks.


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## bazmak (Dec 14, 2014)

Hi macripper,i have the 16" bed and i am thinking of doing the the taper gibs to the front as you cant adjust the front gib withou stripping down the carriage,as you say the back gibs are not as important and can be adjusted without stripping the carriage.The new gib plt works well and does not cause any problems,also i may be able to use it to nudge over carriage a couple of thou to square up the cross slide


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## MCRIPPPer (Dec 14, 2014)

you should not use the extra gib you made to adjust for square. that wont work. you need to machine the dovetails again if you want to make the cross slide perfectly square to the carriage movement.

build new tapered gibs for front and back.


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## goldstar31 (Dec 15, 2014)

Actually, there is NO reason why a saddle cannot be modified to skew it further into alignment provided that rigidity( whatever that translates to on a cheap Chinese affair) is maintained. 

I was going through the specifications of the old Pools lathes and noted that mine- a Pools Major had totally different gibs and a mechanical power feed to anything described in Lathes Co Uk site.  Again, I had access to a Murad Antarctica  when I put it on a tug boat to go down to Queen Maud Land. It was similar to the Bormilathe( which most have never heard of) but a variant is Jack Radfords Elevating heads in his excellent book- which no one will have ever read. People are missing a helluva lot when people simply become disenchanted.

 I can cock mine over on the Myford -because I can go off the rear shear. 
It may be only fine milled but go off it, you can. In this day and age, superb plastics are the norm as bearing surfaces. The days when a scraper with his sleeves deep in black cast iron and wearing spectacles made out of thick Newcastle Brown Ale bottles are past. Don't get me wrong- I can scrape  but I usually spend my scraping to removing mould on my villa walls  in Spain! It is worth more and my wife gives me a beer!


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## bazmak (Dec 15, 2014)

I understand that the rear gib plt should in theory not be necesarry,however
it has sorted out my problem,even though it is only just touching.I also think
that it can be used to skew over the carriage (say a couple of thou) to help square up the carriage,not good practice but will help.Only time will tell


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## goldstar31 (Dec 15, 2014)

Ah, Barry, you should get Connolly's Machine Tool Reconditioning. Great book, it is big , thick and comprehensive. If a leg falls off the bed or the car has a puncture you can use it as a spare leg or stand. Again, if you are insomniac, it is the finest way of going to sleep if your are not a Kiwi.

Oh, and in case you are wondering, it does tell you how to make a silk purse out of a sows ear. 

It doesn't tell readers how to make sufficient money to get a better lathe- but one cannot expect miracles.
These, I believe, came out of the East. There is a book on that as well but I missed them- the first time round.

Anyway, Merry Christmas to all our readers and the ones who cannot, I apologise for not photographing -when I was there.

Cheers

Norman


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## ShopShoe (Dec 15, 2014)

bazmak,

I'm following this thread and I have a 7x lathe. I have had to address this problem at least twice. 

I can also say that I was originally plagued by gib screws continually working loose, which has also been mentioned by many owners of these lathes. Better-quality screws and nuts and sometimes new tapped holes are needed.

I am conservative when it comes to modifications. I start slowly and work up to "better" a step at a time and things really do get there in the end.

Back to the problem in hand: I don't have the measurements to hand, but my lathe's problem is that the measurements vary depending on the distance along the bed (14-inches in my case). It appears to "belly" near the tailstock end, like the lathe here:

http://madmodder.net/index.php?topic=627.0

(Too bad the photos have been moved)

 In addition, the serial number stamping distorted the bed in that area.

My next major effort at improvement will be an attempt to totally disassemble the lathe and attempt to actually determine whether the bed can be improved by scraping, maybe even grinding, but this may end up proving I need a new bed.

Meanwhile, things with this lathe are OK enough for my present operations that I can do well in my usual work envelope near the headstock: I only have to worry if I would want to turn a long length between centers, which I seldom need to do.

So, I originally made a part like yours and that was good enough for about a year. The next iteration included a remake of both sides, lapping and shimming: Better. If I can determine the bed is workable or end up with a new bed, then I will probably go the tapered-gib route.

If you haven't read this, also see here:

http://www.homemodelenginemachinist.com/showthread.php?t=8306&highlight=Beginning+Mini-lathe

I can also recommend the Connolly book. Not used every day, but worth having to see what would be done in a perfect world (circa 1954). It is a good idea to get the whole theory down, otherwise it is possible to "correct" via a compensation that creates another need for a compensation-for-the-compensation further down the road. 

I have been following your various projects and I have no doubt you will do something  and I will be watching whatever you post on this.

--ShopShoe


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## bazmak (Dec 15, 2014)

Do me a favour shoeshop.When you have time please check and post the 3 dims requested.Next time you reove the apron and disconect the leadscrew
set the gibs to a nice sliding fit and then twist the carriage ACW and CW let me know if there is much play. Regards Barry


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## ShopShoe (Dec 16, 2014)

bazmak,

I've just been out to the shop for the measurements. I believe I am measuring what you asked for, but I could also be confused.

1. The width of my bed varies from 3.244 to 3.247 inches over the length of the bed, measured in five places multiple times. Just as I said, the larger measurement is at the tailstock end, near the area where the serial number is stamped.

2. The milled-out area of the saddle (carriage) measures from 3.322 to 3.326. I do not have an extremely accurate way to measure this in the center of the saddle and I do know that the outer ends are "bell-mouthed" a little (lets say the outermost 3/16-inch).

3. Using feeler guages, I get something like 0.039 gap in the front and 0.032 in the rear. Once again, I wish I had a more accurate way to measure this. After earlier work, I have the main travel of the saddle located and stabilized by the front and back of the prism. My carriage does not try to climb up the prism as you were describing. My front gib clears the rack and gear by a good margin.

4. With the saddle sliding freely and smoothly, but not yet as uniformly as I would like, and checking movement with a dial indicator, I can get the back side to lift a maximum of 0.0015 at the loosest point. I can not get the front side to change more than 0.0005 under considerable pressure, which I consider good for this lathe at this point in time. The important thing (to me) is that the amount of slop that shows up at the tip of the cutting tool is very minimal in the normal direction of rotation. 

I believe that I can eventually get the bed evened out more (or replace it) and then put in the tapered gibs and get this even better.

I hope this is what you were looking for.


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## Brian40 (Dec 18, 2014)

Hi Bazmak
You may find some of the work on my site handy (see bottom of page) feel free to down load any of the PDF's you think handy, the one on adjustable gibs may be of particular interest. I am always available to help.

 I haven't Touched the gib's on my lathe for three years and it is worked hard with a 1HP motor
 If you look at my 32x40 H gas engine thread you will see just how hard.
 Brian*.*


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## bazmak (Dec 18, 2014)

Many thanks Brian,just had a quick browse.Many thanks for the PDFs very interesting and opened up some problem areas that i have thought about
that you have appeared to have solved.I like the gibb plts with top adjustment screws and will make a decision on your idea pr try tapered gibs now that i have a mill.I like the cross slide nut mod and may try screwcutting a new lead screw for the the cross slid mod.I did the extended cs travel to the front but 
as yet have not found a need for the rear ext. travel.Again many thanks
will post if i do any of your mods. Regards barry


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## zoltan (Feb 19, 2015)

I agree with the other posters here, that you really want the prism locating the carriage and not the back edge of the bed. However, the carriage gibs need to be adjusted well for the prism to do its job.

While tapered gibs would be great, I went a cheaper and easier route which has worked very well for me. I found the biggest problem to be the stock gib adjustment system. It's super difficult to get adjusted correctly and go out of adjustment super fast; it sucks. I removed the small set screws and tried different shims (I use feeler gauge leafs as shims) between the carriage and gib until I found ones which _just_ allowed easy movement. Now everything is nice and tight and solid.

http://benchtopmachineshop.blogspot.com/2014/04/lathe-shimming-carriage-gibs.html

Also, if you want to easily increase the rigidity of your lathe, replace the compound slide with a solid block of steel; I only ever used the compound for threading anyway. That cheap mod alone will help a lot.


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