Tail stock drilling options

[STEVEMORSE]

Hi all. My tail stock is perfectly aligned in both sideways and height I do lots of drilling and reaming useing a chuck. Sometimes a reamer or drill bit does not line up properly with a smaller existing hole. I think it’s my shitty 3 jaw chuck. Is there a collet system available with collet holder and collets. I’m hoping this will solve my alignment issues

 

[EPAIII]

Three posts, so you are new here. You need to understand that this is a professionally oriented forum, not for home shop, hobby people. So you will probably get some directions to read the forum rules. You should do that. And a more appropriate forum for your questions for the near future may be something like:

General -

The Home Shop Machinist & Machinist's Workshop Magazine's BBS

But in answer to your question, just aligning the tail stock vertically and horizontally does not insure that a drill bit held there in a drill chuck or even in a collet will have it's tip on the lathe axis, much less on an existing, "centered" hole in a piece of work held in a three jaw chuck.

The tip of the drill bit will be some distance removed from the end of the tail stock and if the tail stock is not aligned by the vertical and horizontal angles as well as in the two linear dimensions you mentioned, then it will not be on the axis. That could be your problem.

Then, three jaw chucks are a convenient way of holding a piece of stock APPROXIMATELY on their center, not precisely. The main use for three jaw chucks is to quickly hold a piece of raw stock which will then be (partially) machined into a part without disturbing it in that chuck. Once you take it out and try to put it back, it will not be precisely aligned any longer. For additional operations on an existing part you should look toward using a four jaw chuck or collets.

Last, but not least, your drill bit may be bent. That happens in the best of shops, all to easily. Oh, and then the tip of the drill may not be sharpened symmetrically.

I am afraid it's the old, "If something can go wrong, it will."

 

[gbent]

Your best bet is to buy a better drill chuck for your tailstock. You need it anyway. You can also make a holder to allow you to use drills and reamers from your tool post. For smaller deep holes drilling from the carriage is much easier.

 

[dian]

you can get a morse-taper holder for er collets, but you might not need it. there is a trick when center drilling (and even when pre-drilling using a short drill): position the flutes horizontal and after they are almost through the surface pull on the chuck a little. this will result in a centered hole. pushing on the drill with the tollpost is even better.

most of the time, however, it doesnt matter if the tool lines up perfectly , it gets centered anyway.

 

[michiganbuck]

I had a time when I had to run wore out lathes. I found that a tool bit scalp at part but-end would put the end work dead center to the chuck. Yes, follow with a center drill if needing that.

But part center (to the spindle) may not be part OD true if the OD is running out.

That center scalp is so very easy, you just make a facing bit that you can swing around and scalp a simple small bore in the but end..

QT: [I think it’s my shitty 3 jaw chuck.] after turning /boring/raming the part will run near true to the centerline of the headstock..But the section left in a chuck will run out or wobble due to the condition of your chuck. Parting a part off can make the part true...running all features from one end and parting off is good. Running a drill or reamer through and then finishing between centers can be good,
For a part needing fussy at both ends going to between centers can be a good choice.

Few chucks and even collets rarely run dead perfect...you have to understand how to make good/perfect parts with knowing how to cope with machine error. Often the near poorest lathe can make near perfect parts with a good lathe hand running the machine.

 

[michiganbuck]

One quick trick is to have a mild steel center perhaps 1" DIA x 4" long with a center point on one end, and a line-up mark so you can set it back in your 3jaw at the same place for rotation and depth ...You chuck it up and skim turn .005 or so at 60* and have a dead true headstock center. With learning this you can go to between centers in a very short time and run a near-perfect part.

Yes, just dog the part to bump a chuck jaw.

This beats the time to pull the chuck and pop in a center. Then need to put the chuck back on.

 

[STEVEMORSE]

One quick trick is to have a mild steel center perhaps 1" DIA x 4" long with a center point on one end, and a line-up mark so you can set it back in your 3jaw at the same place for rotation and depth ...You chuck it up and skim turn .005 or so at 60* and have a dead true headstock center. With learning this you can go to between centers in a very short time and run a near-perfect part.

Yes, just dog the part to bump a chuck jaw.

This beats the time to pull the chuck and pop in a center. Then need to put the chuck back on.

......I’m not trying to reply with quote but I could not find the reply button. I looked for the forum rules but could not find them. I will try to find them again. Thank you all for taking the time to assist me. It’s good to hear a variety of different ideas. Your ideas have helped me. It forces me to rethink the entire way that I do things , and to think out the best procedure of lathe tasks before I start anything. Sometimes running off to the shop to buy 500 bucks worth of collect holder and collets may not be necessary

 

[thermite]

......I’m not trying to reply with quote but I could not find the reply button. I looked for the forum rules but could not find them. I will try to find them again. Thank you all for taking the time to assist me. It’s good to hear a variety of different ideas. Your ideas have helped me. It forces me to rethink the entire way that I do things , and to think out the best procedure of lathe tasks before I start anything. Sometimes running off to the shop to buy 500 bucks worth of collect holder and collets may not be necessary

Add, then, to your "cheap to do for HIGH value benefit" list, the fabrication of a torque reaction control rod or bar. Look around for examples, or just "figure it out", but the goal is that the twisting force generated when pushing a drill is resisted by a torque arm affixed to the drill holder & male taper, not the poor abused female Morse Taper all by itself. And especially not by the usually TOO small key that prevents rotation of the entire TS quill. Until it fails to do, damaged remains bind the whole shebang up. And NOW you have a problem.

Because there is only the ONE key and the ONE female taper, and it is NICE if it can last - undamaged - for scores of years - whilst the "many" more easily replaced or repaired detached drilling goods come and go.

A soundly built fixture directly mounted to the topslide of the cross AND NOT a tool holder, toolpost, nor even the compound is far better, EVEN IF.. your TS has a capstan, handlever ram, or is a bed-mounted capstan or turret instead of the useless for proper drilling (too DAMNED slow on chip-clear retract..) "handwheel" operated one-hole TS.

Travel, speed, and power-feed thing.

With a carriage-mount?

NOW you have rapid manual in-and-out to clear chips. FAR longer travel. And even gain power feeds. Done intelligently, same rig also mounts your boring-bar arsenal for reduced risk of chatter vs TP & compound mountup.

At least one affordable collet rig is wise. Some among us have "several".
5C is cheap and cheerful if your lathe will support it. Working small-diameter stock with the "usual" 4-J or 3-J chuck is simply put: "an avoidable pain in the arse".

5C also gains you access to easy use of internal expanders. Handy gadgets. Very.

See also Breakheart's inexpensive sets of internal expanders. CNC'ed out of ignorant 12L. So you can afford to custom-machine any of them - more than once - for a really good FIT.. then still have the coin left in-pocket to buy a replacement now and then as one goes below the larger diameter needed, some new tasking.

"tween centers on your dance-card? It should be. Get you at least a cheap-chinee set of expanding mandrels. Those can make the problem of working a pulley or any other "shaft-mounted" goods by their already-existing bore fast and simple instead of slow and difficult.

Some other Brother can explain why we still keep a faceplate or three around, why you may NOT really need a "dog driver" plate, why you best have at least one decent 4-J and a 3-J only "maybe".

3 1/2 CW

 

[dian]

"cheap-chinee set of expanding mandrels":

i have a lot of stuff from ebay but exactly this is the item not to get. they refunded the money and i still have the set. the slits are to short to flex, the thread is messed up and the recess is so rough that you could not expand them anyway. they are fully hardened. maybe i can use them someday somehow as punches or similar.

 

[thermite]

"cheap-chinee set of expanding mandrels":

i have a lot of stuff from ebay but exactly this is the item not to get. they refunded the money and i still have the set. the slits are to short to flex, the thread is messed up and the recess is so rough that you could not expand them anyway. they are fully hardened. maybe i can use them someday somehow as punches or similar.

Well. You got a refund? I got useful goods. AND NOT off ePrey, FWIW-not-much.

I didn't pay a lot for my ones. Three sets, two different makers, IIRC. To cover many sizes. Wasn't "rock bottom", either.

But the finish is fine. They work as they should do. I couldn't make my own for but one or two taskings before I had spent a great deal more time and money than covers a really wide range.

Some importers actually know which is which and give a damn. They are themselves expatriate Chinese, speak and read the language, know whom to ask to vet credentials.

So they WOULD know!

Others?

Not so much!

寄件者

 

[richard newman]

I had a time when I had to run wore out lathes. I found that a tool bit scalp at part but-end would put the end work dead center to the chuck. Yes, follow with a center drill if needing that.

But part center (to the spindle) may not be part OD true if the OD is running out.

That center scalp is so very easy, you just make a facing bit that you can swing around and scalp a simple small bore in the but end..

I'm feeling dumb today - what is a "tool bit scalp"?

 

[thermite]

I'm feeling dumb today - what is a "tool bit scalp"?

"Old Indian trick?"

 

[DDoug]

I'm feeling dumb today - what is a "tool bit scalp"?

"Facing at an angle".....

 

[dian]

Well. You got a refund? I got useful goods. AND NOT off ePrey, FWIW-not-much.

I didn't pay a lot for my ones. Three sets, two different makers, IIRC. To cover many sizes. Wasn't "rock bottom", either.

But the finish is fine. They work as they should do. I couldn't make my own for but one or two taskings before I had spent a great deal more time and money than covers a really wide range.

Some importers actually know which is which and give a damn. They are themselves expatriate Chinese, speak and read the language, know whom to ask to vet credentials.

So they WOULD know!

Others?

Not so much!

寄件者

so where to get decent ones?

 

[Mtndew]

so where to get decent ones?

Anywhere but China

 

[thermite]

so where to get decent ones?

Near you? There is.. or WAS .. at least ONE importer in DE that deals in the better goods that German Industrial, not "hobby", users will tolerate as value-for-money.

Mind - that was prior to "World-War-COVID."

I no longer send money that direction.

Might not be the fault of their industrial folk, but why fund evil, however indirectly?

Looking more to Brazil or India these days if not US, UK, or European.

 

[richard newman]

"Facing at an angle".....

Thanks, you won't believe what comes up if you google "scalping on lathe", horrific!

 

[michiganbuck]

Quote Originally Posted by richard newman View Post
I'm feeling dumb today - what is a "tool bit scalp"?

Just about any drill or reamer will follow the existing hole, a center drill will be deverted by a facing nub, even a poorly sharpened drill point can start off or wander off when first penetrating.
The tool bit scalp is to come in with a tool bit and make a cut that acts like a boring start. It will be dead center to the center of the part. Much needed if you have little stock and need the part but end exactly on center..Yes if the Od is running from the centerline it will still have that error.

I found that sometimes you can 4jaw a part and then put in a center drill, a drill a hole or whatever and still be off-center. If you have enough turning stock it doesn't matter, but if you want it near zero that tool but scalp can help..

 

[cyanidekid]

Quote Originally Posted by richard newman View Post
I'm feeling dumb today - what is a "tool bit scalp"?

Just about any drill or reamer will follow the existing hole, a center drill will be deverted by a facing nub, even a poorly sharpened drill point can start off or wander off when first penetrating.
The tool bit scalp is to come in with a tool bit and make a cut that acts like a boring start. It will be dead center to the center of the part. Much needed if you have little stock and need the part but end exactly on center..Yes if the Od is running from the centerline it will still have that error.

I found that sometimes you can 4jaw a part and then put in a center drill, a drill a hole or whatever and still be off-center. If you have enough turning stock it doesn't matter, but if you want it near zero that tool but scalp can help..

turned center depression as opposed to drilled center hole is the quick way to describe it.

yes the nub will throw a drill off much of the time, and it is relying on rigidity and alignment to get on center even if the nub doesn't, so a turned center is going to be a more reliable. it will be aligned with the spindle centerline, but as to the center of the work, only in so much as its mounted true. any runout will be reflected in the position of the center.

none of this relates to the original question really though, which was why a drill wouldn't follow a smaller pilot.

that likely isn't caused by the chuck, the lathe, or the accuracy of the center hole. its probably the drill, and its grind and how it starts the cut. chatter will throw it off, as will a bad grind.

tell us what size drill, what type and length (new premium 135 deg. screw machine drill? cheap 118 deg jobber drill resharpened with a nail file?), what size pilot, what material, what hardness/heat treat, what speed, how is it held, what is the indicated runout, how long is it, what are you holding the drill with, was the pilot made on the same setup, then we can get a little closer to what is actually going on...

P.S. this thread takes the cake for responders not bothering to read the first post well. LOL! all over the place...