Lathe

[Jlg]

Put a clock gauge on the bed, with pointed on the cross slide. Take a cut and see how much the cross slide is moving. For a better finish, if the tool is right, you need to remove movment. While the bits still operate smoothly. Also find the right feed rate.

Clock the spindle too see how much thats running out...is there any vibration. Though the finish on your riser block looks far better.

For a quick center height, put rule or similar between the tool tip and work. As you alter tool height the rule moves, when its vertical, you are at center height.

I'll give that a go and yes the finish is better on the riser block I don't know why

 

[Jlg]

So I let my brother use it and he was talking to deal of a cut and kept doing it till I took it off him but now I get a lot of chatter of it when I try to take a cut of aluminium

 

[eLuSiVeMiTe]

So I let my brother use it and he was talking to deal of a cut and kept doing it till I took it off him but now I get a lot of chatter of it when I try to take a cut of aluminium

Check for play in the cross and compound slides and tighten/adjust as required. Did you check for play in spindle

 

[Jlg]

Check for play in the cross and compound slides and tighten/adjust as required. Did you check for play in spindle

No play in spindle it was fine till he started trying to take 3mm cuts how do you tighten the cross slide

 

[eLuSiVeMiTe]

No play in spindle it was fine till he started trying to take 3mm cuts how do you tighten the cross slide

One side against the dove tails will have a metal strip. Probably parallel on yours. Dog point screws through the casting will push this tighter against the dovetails.

Wait one and il look for a vid.

 

[eLuSiVeMiTe]

Should give you an idea.

 

[Jlg]

One side against the dove tails will have a metal strip. Probably parallel on yours. Dog point screws through the casting will push this tighter against the dovetails.

Wait one and il look for a vid.

I've checked all that and it's ok I've taken the cross slide off to degrees it all and found out that the lead screw nut is extremely worn there is a lot of play in it

 

[Gritineye]

Play or backlash in lead screws will not affect the accuracy at all, what it does affect it the way the machine feels and how you adapt to the slackness.

When making normal cuts wind the carriage or cross slide out until you can make enough turns in again to take up the slack well before the tool contacts the work, the tool pressure then holds everything in place.

Opposite when internal cutting, and the same principles when threading or facing, it just takes practice and soon you won't notice it.

A lot of good lathes have been passed up because of folks over fussiness about backlash, in my opinion that is!

 

[Jlg]

Play or backlash in lead screws will not affect the accuracy at all, what it does affect it the way the machine feels and how you adapt to the slackness.

When making normal cuts wind the carriage or cross slide out until you can make enough turns in again to take up the slack well before the tool contacts the work, the tool pressure then holds everything in place.

Opposite when internal cutting, and the same principles when threading or facing, it just takes practice and soon you won't notice it.

A lot of good lathes have been passed up because of folks over fussiness about backlash, in my opinion that is!

It's more the fact I can rock the nut side to side by about 4mm each end that makes me want to get a new one

 

[Seadog]

Play or backlash in lead screws will not affect the accuracy at all

Up to a point that's true. In practice there's more wear in one section then the rest and the wear is not linear. Consequently you cannot rely on the handwheel graduations.

 

[Jlg]

It's more the fact I can rock the nut side to side by about 4mm each end that makes me want to get a new one

Plus I don't want to put any un nesacery wear on the lead screw as its got very little wear if you measure a part in the well used part and a bit at the very end theirs only 0.2 of a mm difference

 

[Jlg]

Does anyone know what thread the lead screw is

 

[rtbcomp]

Play or backlash in lead screws will not affect the accuracy at all, what it does affect it the way the machine feels and how you adapt to the slackness.

When making normal cuts wind the carriage or cross slide out until you can make enough turns in again to take up the slack well before the tool contacts the work, the tool pressure then holds everything in place.

...

Also the tool can be drawn in due to backlash. I get round this by doing as above and then winding out until the backlash is just taken up without moving the tool. You have to get it at the right time, ie once the cut has started but before the tool gets dragged in. Most notable when parting off.

 

[God mode restorations]

Also the tool can be drawn in due to backlash. I get round this by doing as above and then winding out until the backlash is just taken up without moving the tool. You have to get it at the right time, ie once the cut has started but before the tool gets dragged in. Most notable when parting off.

This is true. I had this on my Mellor lathe. The tool would drag in slightly

 

[Gritineye]

It's more the fact I can rock the nut side to side by about 4mm each end that makes me want to get a new one

Picture needed...

Up to a point that's true. In practice there's more wear in one section then the rest and the wear is not linear. Consequently you cannot rely on the handwheel graduations.

I only rely on the hand wheel graduations when roughing, mike when getting within the danger zone..

Also the tool can be drawn in due to backlash. I get round this by doing as above and then winding out until the backlash is just taken up without moving the tool. You have to get it at the right time, ie once the cut has started but before the tool gets dragged in. Most notable when parting off.

Maybe so but I've never had that happen, I do have a thumb screw for one of my my cross slide gibs screws and snug it up for fine work though, or maybe be it's how I grind my tools. I can see why it would happen when parting if the set up is a little off.

Tool room machinist mate has ancient lathes and mills in his shed, does perfect work despite backlash on everything, he reckons even a new machine has backlash, you just adapt to the amount on different machines around the shop, all part of the skill..

 

[God mode restorations]

4mm of movement in the nut says one thing.
It's shot. I get in a panic if there's a quarter of a millimetre

 

[Jlg]

4mm of movement in the nut says one thing.
It's shot. I get in a panic if there's a quarter of a millimetre

I get over a full turn of the handle before anything happens compared to the cross slid a 10th of a mm turn on the handle starts to move it

 

[addjunkie]

Does anyone know what thread the lead screw is

Measure it

 

[eLuSiVeMiTe]

4mm of movement in the nut says one thing.
It's shot. I get in a panic if there's a quarter of a millimetre

Don't panic too much mate. To tight a setup is going to introduce wear quicker no?Better of dealing with a little backlash

 

[God mode restorations]

Don't panic too much mate. To tight a setup is going to introduce wear quicker no?Better of dealing with a little backlash

Yes a little is acceptable. 4mm is not so good