Lathe cross slide

Status
Not open for further replies.
Hi Stuart,
The work piece is 20mm dia, being a newbie I don't have too many accessories as yet. I've a dial test indicator on order, and other bits and bobs off ebay. I spent the first two days setting up the lathe to my work bench. The bench is heavy steel framed with railway sleepers as the work surface,(concrete floor) so I'm assuming its a solid base. It's mounted in a steel swarf tray and I added leveling feet to the lathe.
I changed the motor from a 1/6 HP to a 1/2 HP and beefed up the countershaft with pillow block bearings. I'm not entirely happy as yet as I have a slight vibration on the countershaft due to the large diameter pulley running a little eccentric. Something to sort out a bit later. The lathe bed has one or two "chips" at the chuck end, but with a lathe of this age I think this is acceptable? I could only set up the lathe bed with a normal spirit level and I made it as square as is possible by this method. I have a Myford manual and Lathework a complete reference books, and have tried to set it up as best I can using the info in these books.
Having an experienced machinist willing to help is the best teacher, many thanks for you time and effort.

Warren

Warren
 
You need to ensure the lathe bed is level to itself. Using a normal carpenter's spirit level just isn't good enough. You need something with high sensitivity/accuracy. Either a machinist's level or doing the 2-collars method of alignment testing seems like it would help you here.
 
Last edited:
Warren,

Can you possibly post a picture of your lathe? I still don't understand what you're trying to do or why you want the compound to be parallel with the lathe ways. The carriage moves parallel to the ways unless the headstock in not aligned, which is rare. Do you have a carriage on your lathe? Does it move right and left? If so, it moves parallel to the ways and will cut parallel with the ways. I need a little more explanation and am more than willing to help you solve your problem.

Steve
 
jeddah02 said:
Hi Stuart,
The work piece is 20mm dia, being a newbie I don't have too many accessories as yet. I've a dial test indicator on order, and other bits and bobs off ebay. I spent the first two days setting up the lathe to my work bench. The bench is heavy steel framed with railway sleepers as the work surface,(concrete floor) so I'm assuming its a solid base. It's mounted in a steel swarf tray and I added leveling feet to the lathe.
I changed the motor from a 1/6 HP to a 1/2 HP and beefed up the countershaft with pillow block bearings. I'm not entirely happy as yet as I have a slight vibration on the countershaft due to the large diameter pulley running a little eccentric. Something to sort out a bit later. The lathe bed has one or two "chips" at the chuck end, but with a lathe of this age I think this is acceptable? I could only set up the lathe bed with a normal spirit level and I made it as square as is possible by this method. I have a Myford manual and Lathework a complete reference books, and have tried to set it up as best I can using the info in these books.
Having an experienced machinist willing to help is the best teacher, many thanks for you time and effort.

Warren

Warren
Click to expand...

Hello,

a short length of matirial wont bend too much at that diamitor (any one with some examples of lengthes hanging out the chuck feel free to jump in), i've been having a lot of work piece bending issues with some <6mm shafts i'm working on just popped to mind as a possibility.

I did have some issues with the head stock bearing clamping presure applied by the bolts holding the split part of the head stock casting. Took a little fiddling with to get a nice balence of low friction and spindle rigidness. Does/can the chuck wobble if you apply some side to side or up down presure?

Bench sounds quite solid. :-)

Asked about chips on the ways as i have one chip that causes a slight bump as the sadle pases over it on heavy cuts.

Maybe a photo of your work piece set up will help with sorting the prob.

Stuart
 
Hey Warren-

I think you should make your test cuts or use an indicator once each on scrap, and mark your compound in some way at each of your most common angles. 90, 45, 60, 30, 0 degrees. Then no more guesswork.

I do agree with Steve's question regarding your reason to make it parallel to the bed ways?


Bernie
 
Hi and thanks to everyone for there replies.
I have made all the adjustment and check on the cross slide and top slide but this problem keeps reappearing.

The top slide should move parallel to the work no matter what angle it is set at but I still measure a taper on the work when the top slide angle is only slightly moved.
The following checks have been done.

1. The top slide checked for free play and adjusted to be slightly tight.
2. The cross slide checked for free play and made slightly tight.
3. The chuck checked for any movement (none found) and the bearings adjusted.
4. The lathe mounting check for any movement.
5. The top slide adjusted to be as close to 0 as possible.(this is the root of the problem, as slight movement off 0 provides eithr positive or negative taper, up to 0.5mm in some cases.)

View attachment 50991View attachment 50992

The pictures may help in diagnosis.

Thanks
Warren
 
Warren,

Your pictures didn't come thru.

I'm still not understanding the issue. Are you making a cut by advancing the lathe carriage or are you making the cut by advancing the top slide/compound? If you are using the carriage, then the angle of the top slide/compound makes no difference. If you are using the carriage and cutting a taper, the headstock is not aligned with the ways of the lathe.

Steve
 
Hi Steve,
I making the cut by advancing the top slide towards the chuck. I'm taking as little off as possible and using a slow speed. The work piece is 20mm dia with 100mm hanging out of the chuck. As you7 say, I expected a parallel cut but this taper cut has really "got me going crazy". If I move the top slide angle by the smallest amount in either direction the taper becomes either positive or negative with respect to the chuck end.
With this in mind I tried to get the top slide at exactly 0 deg (90 deg to the chuck face) but without any angle markings it seems to be a real pain to find the point where a parallel cut can be made. I shall try and send the photos again.
(We call the carrier with the tool clamp the cross slide.)

Warren
View attachment 51011

View attachment 51012View attachment 51011
 
Hi Warren,
If you move the "top slide" either side of zero, you will, of course, get a taper when you move the top slide, right? One of the earlier photos showed a carpenter's square held against the chuck showing a gap on the top slide side. If you were to hold a carpenter's square against the chuck face and bring the top slide to bear against the 90 degree leg of the square and adjust it as close as you can to align with that leg of the square you should have the top slide set to 90 degrees. Then when you move it either towards or away from the chuck it should give you a parallel cut as opposed to a tapered cut. If not then I would check the angle of the chuck face to the lathe ways to make sure that angle is 90 degrees.
Hope this helps.
NodakGary
 
Warren,

Still no pictures. There is a sticky somewhere on the home page that explains how to post pictures.

Here's the best advice I can give you without seeing a picture of what you are trying to do:

Set the top slide/compound to 29 degrees. Lock it and leave it. Make your X-axis cuts with the carriage. Done.

Steve
 
Status
Not open for further replies.
Back
Top