Lathe tolerances.

[CuesDirectly]

Time for a thread on lathe tolerances?

Perhaps I can get it started, this is not aimed at those with the ability to set up a lathe, more for those who do not.

Simple facts to know; All import lathes come from the factory with the tailstock 3-5 thousands of on inch hi, no problem if you know how to handle it.

Unless you purchase the very expensive Precision Lathe, you will need a new chuck as well, factory chucks are boat anchors.

Set true checks are only perfect at the spot you zero them in at, they are still scroll chucks in all other positions. My Father used to purchase soft jaw chucks all the time. If he had 1,000 parts to machine and they were 1.5" he would have one that was set to scroll to perfection at that size. When he would use the same lathe and machine parts that were 1" in diameter, he would use a different soft jaw chuck set to that diameter, never would one be used for the other size. On the set true chuck I use, I zero it at the diameter of my Collets. It has zero runout inside the collett.

Full size lathes cannot be purchased and used for cues right out of the box for many reasons, my breakfast is done and I don't have time for all the reasons but we have some great talent here to share their own experiences.

Setting your lathe properly before your first cue can save years of misery. Learn all your runouts before your first cuts on any material.

Thanks, Dave.

 

[CroweCues]

Nice post. The last statement should ring home to everyone!

Sent from my SM-G925V using Tapatalk

 

[conetip]

Dave, there are precision scroll chucks, where the scroll maintains it's accuracy over the entire griping range. Not sure if they are even made any more, but they used to be. These chucks would hold a round part to 0.005mm TIR when new and if not abused or over tightened. Then there is the adjustable chucks. Some of these were a combination of the super precision chucks and being adjustable. In latter years, due to costs, the super precision scroll was not done, just the adjustable aspect. These chucks only repeat on a particular size. I have 2 Burnerd Grip-True chucks. 1 is a super precision version that was only made for a very short time frame, the other is the one that most people who brought a Grip True would have brought. The better one, stays within 0.01mm even today over the range of the chuck. The other one can be as much as 0.1mm out from a 6mm pin to a 25mm pin. A real pain actually. The super precision chuck really is quite high maintenance if you want to keep that precision level high. They need a regular service , at least 1x a year of complete strip down and thorougher clean lube and reassemble. Of course , many don't do this and the wear occurs and then it's no longer a precision chuck. I have also noticed that the standard chuck acceptable run out these days is really terrible, it's like 4 to 6 thou. Even at 4 thou it is in my view a waste of time. Sometimes you do get lucky and the chuck that comes with the lathe is better than 0.02mm over its range, but is quite rare these days. The most common miss use of chucks is over tightening them, especially when a partial jaw depth of engagement is being used.
Neil

 

[qbilder]

I began learning machine trade as a young teen. It didn't take me long to realize that a chuck RARELY tightens to the same point every time, so a piece can be chucked & un-chucked repeatedly until it's at a satisfactory run-out. It was no different on the old iron as it was newer Chinese machines. Precision machines could be inaccurate and utility machines could be precise. As much depended on the user as it did the particular machine.

 

[CuesDirectly]

Thanks.

Dave, there are precision scroll chucks, where the scroll maintains it's accuracy over the entire griping range. Not sure if they are even made any more, but they used to be. These chucks would hold a round part to 0.005mm TIR when new and if not abused or over tightened. Then there is the adjustable chucks. Some of these were a combination of the super precision chucks and being adjustable. In latter years, due to costs, the super precision scroll was not done, just the adjustable aspect. These chucks only repeat on a particular size. I have 2 Burnerd Grip-True chucks. 1 is a super precision version that was only made for a very short time frame, the other is the one that most people who brought a Grip True would have brought. The better one, stays within 0.01mm even today over the range of the chuck. The other one can be as much as 0.1mm out from a 6mm pin to a 25mm pin. A real pain actually. The super precision chuck really is quite high maintenance if you want to keep that precision level high. They need a regular service , at least 1x a year of complete strip down and thorougher clean lube and reassemble. Of course , many don't do this and the wear occurs and then it's no longer a precision chuck. I have also noticed that the standard chuck acceptable run out these days is really terrible, it's like 4 to 6 thou. Even at 4 thou it is in my view a waste of time. Sometimes you do get lucky and the chuck that comes with the lathe is better than 0.02mm over its range, but is quite rare these days. The most common miss use of chucks is over tightening them, especially when a partial jaw depth of engagement is being used.
Neil

Thanks for the great response, it sounds like you use a very nice setup and that you know how to keep it maintained. These set tru chucks are very nice, they are extremely accurate thru out the entire range. They do advertise 0.0005" repeatability but I find perfection at the point it's zeroed in at, for me it's the diameter of my collets and I get zero runout on the inside of my collets.

The chuck is only one item to be checked for runout and people buying new lathes with no experience should know them all before turning their first piece of wood. I can tell you know them very well, that's why it was a pleasure reading your comments.

Thanks again, Dave.

 

[CuesDirectly]

I began learning machine trade as a young teen. It didn't take me long to realize that a chuck RARELY tightens to the same point every time, so a piece can be chucked & un-chucked repeatedly until it's at a satisfactory run-out. It was no different on the old iron as it was newer Chinese machines. Precision machines could be inaccurate and utility machines could be precise. As much depended on the user as it did the particular machine.

Try a Zig Zag rolling paper on one of your jaws next time you find yourself retrying over and over but a chuck set up right should not give you these problems.

If someone paid the price for a precision lathe and it was not accurate, wow, who made it? Some are so precise that the runout is measured in the millionths of an inch. Who made the one you found so bad?

Thanks for chiming in, I appreciate your comments.

 

[qbilder]

My point wasn't to bash or brag on any machine, but to point out there are many, many other variables to consider than your lathe's TIR. Case in point, if you pick up a McDermott & roll it on the table and it appears straight, the joint is flush, and finish is clean, would you consider it a fine cue? Nothing about it was precision machined, but it's as precise as a human can detect with his/her God given senses. That's our bar, and anything beyond it is diminishing returns. The joint pin being within .0001" of center as opposed to .001" of center makes absolutely no difference. To be totally honest, .001" is dang impressive on a cue. Our medium is wood, which is rarely if ever round or smooth enough to achieve the TIR numbers you mention. So to play devil's advocate, at exactly what point does precision produce diminishing returns? There are many other critical facets of cue making that a guy has to learn and focus on, so how much does he really need to focus on precision? The difference between .0001" and .001" is many thousands of dollars, lots of time, finer measuring utensils, and for what gain?

 

[CuesDirectly]

My point wasn't to bash or brag on any machine, but to point out there are many, many other variables to consider than your lathe's TIR. Case in point, if you pick up a McDermott & roll it on the table and it appears straight, the joint is flush, and finish is clean, would you consider it a fine cue? Nothing about it was precision machined, but it's as precise as a human can detect with his/her God given senses. That's our bar, and anything beyond it is diminishing returns. The joint pin being within .0001" of center as opposed to .001" of center makes absolutely no difference. To be totally honest, .001" is dang impressive on a cue. Our medium is wood, which is rarely if ever round or smooth enough to achieve the TIR numbers you mention. So to play devil's advocate, at exactly what point does precision produce diminishing returns? There are many other critical facets of cue making that a guy has to learn and focus on, so how much does he really need to focus on precision? The difference between .0001" and .001" is many thousands of dollars, lots of time, finer measuring utensils, and for what gain?

You're the one who said you found a Precision Lathe to be not very accurate. I do agree that wood does not need to be measured by the millionth of an inch. If you use a crappy chuck, go ahead and stay with it. Until tomorrow, Thanks.

 

[JoeyInCali]

Time for a thread on lathe tolerances?

Perhaps I can get it started, this is not aimed at those with the ability to set up a lathe, more for those who do not.

Simple facts to know; All import lathes come from the factory with the tailstock 3-5 thousands of on inch hi, no problem if you know how to handle it.

Unless you purchase the very expensive Precision Lathe, you will need a new chuck as well, factory chucks are boat anchors.

Set true checks are only perfect at the spot you zero them in at, they are still scroll chucks in all other positions. My Father used to purchase soft jaw chucks all the time. If he had 1,000 parts to machine and they were 1.5" he would have one that was set to scroll to perfection at that size. When he would use the same lathe and machine parts that were 1" in diameter, he would use a different soft jaw chuck set to that diameter, never would one be used for the other size. On the set true chuck I use, I zero it at the diameter of my Collets. It has zero runout inside the collett.

Full size lathes cannot be purchased and used for cues right out of the box for many reasons, my breakfast is done and I don't have time for all the reasons but we have some great talent here to share their own experiences.

Setting your lathe properly before your first cue can save years of misery. Learn all your runouts before your first cuts on any material.

Thanks, Dave.

And most of the time, you will need to mount the back plate and face it before mounting the chuck.
We all wish we own a Monarch with a collet closer.

 

[conetip]

Most of the super precision chucks I have seen, only have 1 key position, instead of the usual 3 or 4 that most chucks have. They also have a shorter handle on the key. It is intended to prevent people from over tightening the chuck.
Neil

 

[qbilder]

You're the one who said you found a Precision Lathe to be not very accurate.

If you read what I posted, it's pretty clear that my point was that an idiot can screw up with precision machine and a master can achieve success with a turd. I wasn't referring to any particular machine, but the monkey behind the controls.

I do agree that wood does not need to be measured by the millionth of an inch. If you use a crappy chuck, go ahead and stay with it. Until tomorrow, Thanks.

I think you mistook the tone of my post. I'm not being condescending or argumentative. Please do not mistake my forwardness as hostility. You began a thread to discuss machine accuracy. I asked the question, with basis and background, what level of accuracy is acceptable & at what point is it unnecessary. In other words, what's the difference between .0001" and .001" as it relates to a cue? At what point is a machine accurate enough to produce a good cue?

 

[pdcue]

My point wasn't to bash or brag on any machine, but to point out there are many, many other variables to consider than your lathe's TIR. Case in point, if you pick up a McDermott & roll it on the table and it appears straight, the joint is flush, and finish is clean, would you consider it a fine cue? Nothing about it was precision machined, but it's as precise as a human can detect with his/her God given senses. That's our bar, and anything beyond it is diminishing returns. The joint pin being within .0001" of center as opposed to .001" of center makes absolutely no difference. To be totally honest, .001" is dang impressive on a cue. Our medium is wood, which is rarely if ever round or smooth enough to achieve the TIR numbers you mention. So to play devil's advocate, at exactly what point does precision produce diminishing returns? There are many other critical facets of cue making that a guy has to learn and focus on, so how much does he really need to focus on precision? The difference between .0001" and .001" is many thousands of dollars, lots of time, finer measuring utensils, and for what gain?

Can we make this post a sticky for the Cuemaker section...

I have been quietly harping for years - 95% of most cues is wood and plastic. Both of which
move and shift over time regardless of how precisely they are machined.

That is not to say the OP did not illustrate some vital points. Esp about learning your lathe FIRST.

IMHO - be as precise as you can within reason. I have a workhorse Metal lathe. I have no trouble
machining closer tolerances than a cue will hold on to.

Dale

 

[Tommy-D]

This kind of reminds me of a conversation I had with my machine shop instructor.

I had been reading on here and on some of the machining forums about the so-called "gunsmithing" lathes.

When I asked my instructor about it,he said that although those lathes typically have a few features that are geared specifically towards processes common to gunsmithing like a good steady/follow rest,that ANY decent lathe can be a gunsmithing lathe WITH THE RIGHT HANDS ON IT :wink:. Tommy D.

 

[CuesDirectly]

And most of the time, you will need to mount the back plate and face it before mounting the chuck.
We all wish we own a Monarch with a collet closer.[/QUOTE

If I recall from past comments, you own a Monarch, very nice.

It's been over five years since I put that backing plate on and faced it. You know the process and I am sure many others in here do as well.

Thanks for the nice comments, Dave.

 

[conetip]

What I find interesting with precision things, is that when a particular technology get to plateau, another comes along and takes it all to the next level. The next level is electron beam polishing/machining. As accurate as lapping but to a contoured face or 3d object.
Just remarkable to see the results of what is possible with the new technology.But none of this is wood working, lol.
Happy New Year to all.

 

[CuesDirectly]

Can we make this post a sticky for the Cuemaker section...

I have been quietly harping for years - 95% of most cues is wood and plastic. Both of which
move and shift over time regardless of how precisely they are machined.

That is not to say the OP did not illustrate some vital points. Esp about learning your lathe FIRST.

IMHO - be as precise as you can within reason. I have a workhorse Metal lathe. I have no trouble
machining closer tolerances than a cue will hold on to.

Dale

Thanks for the response and you're very correct, it's easy to set up a machine to specs above and beyond what a cue needs.

 

[CuesDirectly]

If you read what I posted, it's pretty clear that my point was that an idiot can screw up with precision machine and a master can achieve success with a turd. I wasn't referring to any particular machine, but the monkey behind the controls.



I think you mistook the tone of my post. I'm not being condescending or argumentative. Please do not mistake my forwardness as hostility. You began a thread to discuss machine accuracy. I asked the question, with basis and background, what level of accuracy is acceptable & at what point is it unnecessary. In other words, what's the difference between .0001" and .001" as it relates to a cue? At what point is a machine accurate enough to produce a good cue?

Olive wood works great on a cue. An Olive branch works well in peace and blessed is the peacemaker. Your forwardness is good, I always hated a$$ kissers. I agree with the words you offer. Thanks for the peace offering and all respect back to you, sorry if I was not kind.

 

[Kim Bye]

I think you can chart this fairly easy as a cost/benefit chart. We are making cues not guns or parts for NASA.
A basic 12x36 from Grizzly is just under $3000, and I`m sure you could make fine cues on that lathe with minimal tweaking.
But if you want more accuracy, you could buy something like a Eisen 12x36 for about $4000, add a Bison or Gator 6 jaw chuck, Aloris QCTP and a good live center like a skoda and your total is about $5500. If you know how to clean, lubricate and set up your lathe, you should be good to go. Ofcourse you would need some sort of rear chuck or some other way to hold long workpieces and you would need a taper setup if you plan on doing tapering on the lathe.
Sure you can get more precision than the above setup will give you, but is it worth it?
A toolroom lathe would give you a run out at about 0.0015mm, they start at around $25.000, but I`m wondering if you really would notice the improvement?
Sure if you build +$3000 cues all day long, I can understand that you might want to pay more for good tolerances and high precision repeatability, but for most normal people a setup costing around $5000 will give you all the accuracy you`ll ever need.