Fixing wear in old machines
As I am new too all of this....and my lathe came over on the mayflower....I would like too start tightening my lathe up a bit.....it has some slop in the tool rest cross feeds......and possibly the spindle.....
Where do I start?......the lathe is a "Dalton 6" with flat belt drive.
Has anybody had any experience with these lathes and could tell me something about them?....I have no books on this lathe...but lots and lots of stuff came with it.
I have a set of dividing heads from Grizzly made by YIYEN, Tzu Yen industrial co. ltd. The set is brand new. I have no idea how to use them.....so some manuals are going to be in order.
I would love too take a machinist course at the local vo-tech center in the evenings but just dont have the time to do it.
I also have several sets of starett mic.s and bore indicators, and various measuring devices new still in the box.
Most of this stuff I have had some experience with and know most of the basics.....common sense isnt a problem.....but professional know how is!
Thanks guys for any help you can send this way......I'll get the camera out today and take some pics. of what I have and maybe we can take this a step at a time.
Sounds like an olde but goody type piece of iron! I know nothing about the Dalton but googled just out of curiosity and came up with this site. There are otheres but at quick glance these looked the most promissinig.
looks site looks very good here. http://oldarn.com/dalton/restoring/index.html
I went out and tried to figure out what size lathe this is....
Embossed in the front of the main casting is "Dalton Six"
The bed way (measuring the length of the front V is 30" long.
From the center of the spindle to the V of the bed way (where a turning piece would touch the way) was 4-1/8" approximately.
Would this lathe be a 8" X 30" lathe ?????
The one manual list a 8X30....but mine has the full cabinet stand and looks like the 9X36 picture with the overhead electric motor.
If you infact have an 8" you may have the only known one. One of the web sites I googled suggested that allthough a 8 is listed, no known examples of it have been found. I looked for it again but could not spot it, but, I know its in the first page of googled "dalton lathe" search results.
Last edited by Your Old Dog; 01-21-2007 at 08:27 AM.
What is the proper way too measure the lathe for size?
The British and the Colonists differ in their methods of lathe nomenclature.
A lathe's dimensions are given in center height and length. The Brits use center height, the maximum dimension from center to the bed. We use swing, the diameter of that dimension. It sounds like your machine is around a 9" swing.
The Dalton sounds like an interesting machine, and possibly has some collector value as well. It would be interesting to see some pictures.
Last edited by JCHannum; 01-21-2007 at 08:50 AM.
The 4 1/8 could be anything from a large 6" to an 8", depending on the marketing folks at the manufacturer..... But probably a 6 or 7.
The Daltons I have seen, (almost bought one) were very nice old-timey looking machines with lots of brass and polished steel.
Pretty much a lathe is a lathe is a lathe, until you get to some oddities. So most info for one works on another as far as use. Fixing, adjusting, etc, does differ, depending on details of construction and types of gib, etc.
Slop in cross-feed is really not a problem, but for reference it can be due to several things. Of course one is wear on the screw and nut.
But also the collars or other bearings that hold the screw against end-wise forces can be loose. That will allow the screw to slide end-wise, mimicking slop from wear, if you don't notice the movement. That can allow amounts of total slop that are impossible with wear alone.
Spindle is almost surely plain bearing type. If you mount an indicator obove teh spindle, with the plunger or arm on top of the spindle, you can determine vertical wear. Stick a piece of heavy stock into the spindle hole. Press down firmly, and note reading of indicator. Raise up on teh stock, and see how much the dial indicates the movement is. Anything over about 1.5 thousandths (a number good for S-B 13" lathes) thou would be grounds for considering adjustment, which may be by removing thin shims from between the bearing caps and the headstock casting.
A similar technique can be used for fron-to-back assessment, although that isn't quite as common a wear area.
O.K., I removed the 3 jaw and placed a piece of heavy stock in the spindle....pushed down on the stock and dialed in the dial indicator on the headstock right behind the threads.....dialed to "0".....then pulled up on the stock...... .002 difference.
However...with the 3 Jaw on the lathe and tight.....did the same thing to the same piece of stock mounted in the 3 jaw......sitting still.....dialed in too "0"....pushed down and readings varied with pressure but with nominal pressure..... .006...pulled up and went past "0" to .006 the other way...... ".012 difference".
I take it that is the slop in the spindle causing this as I was taking readings farther from the spindle bearing?
Possibly, I am not sure how you did it..... how much force, where the indicator was for the second measurement, how far in teh heavy stock was, etc.
With any measurement not AT the bearing, you are getting the increased lever arm movement, plus any movement that is due to sliding or tipping of any extra parts between the spindle and the indicator. Possibly also deflection of the spindle, or movement of the stock in the jaws, depending on how far in the stock is and where the indicator tip is put.
The S-B method is without extras attached, as per your first measurement.... right on the spindle collar. They specify, for a larger spindle nose diameter (2 1/4"), 50 to 75 lb force, I think. The stock should go right thru the spindle, or you are producing a bending of the spindle. I suspect this is part of what increased your second measurement, at least.
All you are wanting to measure is actual radial movement of the spindle within the bearing.
The 0.002 total is right in the area of "maybe"....... depending on spindle diameter, and depending on exactly how you did the pulling and pushing, how far the stock was in etc. Remember, stock right thru entire spindle, you want a "handle" not a "lever".
There has to be clearance for oil to "fit" in between the bearing and spindle and form a "wedge" oil film that takes the weight. So there must be some amount of slop. The 0.002 initially sounds a bit over, but I'd repeat, being sure to only apply up and down force, NO bending force on spindle..... stock clear thru spindle.