Tail stock or or chuck clamp first?

[pitnut]

Is it okay to clamp down on a part before engaging the tailstock? I can only grab onto a small portion of the part before a taper messes up the axis of the part. I’m just worried about the tail stock pushing it further into the chuck. 175 tailstock psi 200 chuck psi gripping aluminum with hard jaws

 

[MilGunsmith]

Make a stop block to fit into the chuck. This will stop the work from being pushed into it. If you have soft jaws for the chuck, you can bore them with a stop built in.

 

[just Dave]

Chuck lightly bring center to contact, hold part towards center, rechuck .(loosen tighten)

 

[eKretz]

MG has it. Use a solid stop. I'd stay away from boring soft jaws unless you have a decent quantity of parts.

 

[4GSR]

Are you working on a manual lathe? or is this on a CNC lathe?

 

[pitnut]

Make a stop block to fit into the chuck. This will stop the work from being pushed into it. If you have soft jaws for the chuck, you can bore them with a stop built in.

I ended up using a bolt threaded through my spindle liner plug. Thank you for your reply!

Are you working on a manual lathe? or is this on a CNC lathe?

CNC, its an old okuma.

Thank you for all the replies guys!

 

[just Dave]

Is it okay to clamp down on a part before engaging the tailstock? I can only grab onto a small portion of the part before a taper messes up the axis of the part. I’m just worried about the tail stock pushing it further into the chuck. 175 tailstock psi 200 chuck psi gripping aluminum with hard jaws

It sound like you are running your center to tight!

 

[pitnut]

It sound like you are running your center to tight!

Do you say that because of the PSI or my worries of it pushing in?
What would you normally recommend if it is the PSI?
I am running fan blades so they wobble pretty bad in there and I’m cautious of lowering my pressure.

I’m running off of 10 year old set up sheets with little guidance. I’m trying to get everything updated and running smoothly for others in the future

 

[michiganbuck]

I like to hand-hold the part on the tail center when tightening a chuck, then adjust how much pressure I might use.
Yes, for smaller parts that one can handhold.
Pretty much the same as what just Dave said in post #3.

 

[Garwood]

Sounds like most of the posters here have never used a cnc lathe before. 95% of lathes built in the last 45 years have hydraulic chucks and tailstocks. You set the pressures, you don't "feel while you tighten" anything.

 

[michiganbuck]

Sounds like most of the posters here have never used a cnc lathe before. 95% of lathes built in the last 45 years have hydraulic chucks and tailstocks. You set the pressures, you don't "feel while you tighten" anything.

I will be first to admit I am not a CNC lathe guy..but this thread is in the General forum, not in the CNC forum.

 

[just Dave]

much depends on the physical characteristics of your piece, but as a general rule you should be able to stop rotation of the center with a good two finger grip. Over tight center can cause bow,chatter,ovality and other bad things .

 

[just Dave]

Sounds like most of the posters here have never used a cnc lathe before. 95% of lathes built in the last 45 years have hydraulic chucks and tailstocks. You set the pressures, you don't "feel while you tighten" anything.

No matter what you run you must FEEL to be a good Machinist.

 

[just Dave]

Do you say that because of the PSI or my worries of it pushing in?
What would you normally recommend if it is the PSI?
I am running fan blades so they wobble pretty bad in there and I’m cautious of lowering my pressure.

I’m running off of 10 year old set up sheets with little guidance. I’m trying to get everything updated and running smoothly for others in the future

If I had to chuck it and then bring in center for support only, you are fine. If the center needs to run true with surface you’re machining; center drill after chucking.
Characteristics of your part are paramount and I don’t know yours.

 

[Cole2534]

I will be first to admit I am not a CNC lathe guy..but this thread is in the General forum, not in the CNC forum.

You ever seen a manual lathe with a hydraulic tailstock? Me neither.

 

[Garwood]

No matter what you run you must FEEL to be a good Machinist.

I FEEL like its more important to understand what the tailstock pressure gauge is for.

 

[eKretz]

You can adapt that feel to the proper hydraulic pressure easily enough. I always wondered why they don't have a gauge with actual pounds of force rather than psi. Would make a lot more sense.