how do i drill a straight hole?

snipershot

snipershot

Go ahead.....run for it.
Silver Member
Ok, I've converted a few butts and as far as looks go, I'm somewhat pleased, and they hit good with a shaft I've been using on em. My problem is that the joint doesn't line up with the shaft perfectly. I'm using a taig style lathe. I cut the joint collar and juma joint down flush with the wood and I indicated it and got about .0025 runout. Its not great, but for a simple sneaky its not bad (I aim to get closer to zero when I get a metal lathe). Here's the problem: I indicated my pin and it had .035 runout. I know the pin was straight, and I've had this problem on all three cues I've done so far. I'm using a tailstock with a jacobs chuck, center drilling the hole to start, and slowly drilling my hole with a good quality drill bit. Is it possible my tailstock is off? Can I use a drill bit in my boring bar holder to drill the hole? What other options do I have?(besides getting a better lathe)

Joe
 
First off, you should probably drill undersize and then bore the rest of the I'd. How do u know the pin was in straight? Did u measure TIR before the glue set and compensate for error?
You COULD leave both a few thous over and then take material off while the cue is assembled OR buy some carbide sanding mandrels, which would make all ur butts and shafts match


Sent from my BlackBerry 9800 using Tapatalk
 
Oh boy...
Here you go...
  • Is the lathe leveled?
  • What is the runout on the chuck?
  • Do you have access to a coaxial indicator to check the tailstock?
  • Have you put a dead end on the chuck and tailstock to make sure they are aligned or the tailstock might be lower or higher than the dead center in the chuck...
  • If you are installing a self aligning pin and your answers on the questions above are good, then do the following (installing a 3/8x10 pin with a self aligning barrel at 0.381") :
    - Drill the hole (5/16 drill bit) length of the barrel and thread plus 0.125 so the pin can bottom out
    - Drill another hole at length of the barrel, probably 0.900" with a 3/8 drill bit
    - Use a reamer at 0.381" and then tap the hole
    - Glue the pin and be done with it.
  • If lathe bed is aligned correctly I guarantee you that the process above is always dead nuts. Always check the alignment of your tailstock with your chuck before this procedure.
 
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snipershot said:
Ok, I've converted a few butts and as far as looks go, I'm somewhat pleased, and they hit good with a shaft I've been using on em. My problem is that the joint doesn't line up with the shaft perfectly. I'm using a taig style lathe. I cut the joint collar and juma joint down flush with the wood and I indicated it and got about .0025 runout. Its not great, but for a simple sneaky its not bad (I aim to get closer to zero when I get a metal lathe). Here's the problem: I indicated my pin and it had .035 runout. I know the pin was straight, and I've had this problem on all three cues I've done so far. I'm using a tailstock with a jacobs chuck, center drilling the hole to start, and slowly drilling my hole with a good quality drill bit. Is it possible my tailstock is off? Can I use a drill bit in my boring bar holder to drill the hole? What other options do I have?(besides getting a better lathe)

Joe
Click to expand...
Your jaws may be out of alignment to each other, and will need to be trued up, or your tailstock isn't aligned with the headstock. One question is what are you using to tap with? What is holding the tap, a quality tap head, or just chucking it up in your tailstock? If the tailstock is off, nothing will line up right. Is the forearm held by 2 chucks and goes thru the headstock, or is it only held on the end and then inserted thru a steady rest?
A lot of questions can be answered by taking a precsion ground metal dowel and chucking it up and run a dial indicator over it and see how true the chuck really runs.
Dave
 
pescadoman said:
First off, you should probably drill undersize and then bore the rest of the I'd. How do u know the pin was in straight? Did u measure TIR before the glue set and compensate for error?
You COULD leave both a few thous over and then take material off while the cue is assembled OR buy some carbide sanding mandrels, which would make all ur butts and shafts match


Sent from my BlackBerry 9800 using Tapatalk
Click to expand...

Well, I don't have a small enough boring bar to bore a 5/16 hole. I'm very limited on options with my lathe, hehe. I'm looking for a metal lathe, but I was hoping I could still do some work with mine.

Joe
 
Dave38 said:
Your jaws may be out of alignment to each other, and will need to be trued up, or your tailstock isn't aligned with the headstock. One question is what are you using to tap with? What is holding the tap, a quality tap head, or just chucking it up in your tailstock? If the tailstock is off, nothing will line up right. Is the forearm held by 2 chucks and goes thru the headstock, or is it only held on the end and then inserted thru a steady rest?
A lot of questions can be answered by taking a precsion ground metal dowel and chucking it up and run a dial indicator over it and see how true the chuck really runs.
Dave
Click to expand...

I trued up my jaws after I found out they were off by quite a bit. I indicated the chuck with a brown & sharpe bestest indicator by chucking up maintenece pin and running the indicator over the smooth machined edge. I'm using a tailstock, not another chuck. I am using a $40 tap I bought from atlas, and I'm chucking it up in the tailstock with both the dovetail mount just loose enough to move, and the tension knob just loose enough to move. I tried to use the tool post with the boring bar tonight when I got home, and it was slightly better, but it was still .020 out.

Joe
 
JoeyInCali said:
Bore for final hole
Click to expand...

Where can I get a boring bar that small? I'm trying to put in a 3/8 10 pin, so I've been drilling a 5/16 hole. By the way, thanks for the help on that buffalo horn man, it turned out great! Except for the pin not lining up, lol.

Joe
 
I have still got some 1/4 diameter drill bore tools still available that fit the Taig type lathes.
You need to check that the tailstock is true to the chuck. Not only left right , but also in the vertical plain.
You can use an indicator in the chuck to the centre of the taistock. Another option is to have a piece of rod with centres in each end. then indicate to see where it is.
0.0025 inches in my opinion is a long way out from being true. A selection of shims under the jaws will help.
As been mentioned earlier you can true the jaws for a size.
Check that if your lathe has twin chucks that the chucks are orientated together. ie have the jaws of the chuck be in the same radial alignment. If both are perfectly true it would not matter, but from what I am seeing of the Taig type chucks, they are not to the precision of an engineers lathe chuck.
You might be better off with 4 Jaw independent chucks on each end.Then they can be dialed in,a bit more work but worth it.
Boring the pin hole true and then tapping the hole true is important. But the pin needs to be held in alignment as well.
Often on the Taig type lathes, I find it better to have the end being worked on true in the headstock, while the remainder is supported by either a bearing bushed steadyrest or chuck mounted in a bearing steadyrest that is aligned to the headstock.
Assuming it is round, runout of less than 0.001 inch TIR(Total indicator runout) can be easily achieved.

Have you checked the pin fit before gluing to see how it fits and runs ?
Do the pins you are using have an alignment shoulder on them or are they the full length thread type?
Either way, checking that you can drill, bore tap and have a pin run true is important to establish before trialing on a cue.
Errors normally accumulate hence the term booking effect. A .0025 runout on the handle joint end when faced aligned to a shaft with a similar run out, can leave a situation where the middle of joint of the cue being out of true by .005inches, or they could just by luck cancel each other out.
Hope this helps.
 
Conetips boring bar is great i use it. This is just a thort besides all the good advice from everyone so far. I have a taig lathe and its works great. I had the original 3 jaw set up and ran into problems constantly adjusting. Then i bought Todd's new 4jaw head stock with indexer. It took the lathe to the next level. I have it to .0015 . I check it frequently and only need to adjust the tailstock. This could be a option. Frank
 
Your holes can be dead nuts center, and threads cut dead nuts center to the holes, and still get .0025" runout on the pin, especially if you are bottoming out the pin. There's at least that much slop in the grooves of the threads. You can avoid it by using flat minor style threads, or else grind the threads instead of tapping and cut them to match the OD of the pin, to avoid settling to one side or the other. Otherwise, just a v-groove pin & tapped hole is not good enough for accuracy. Never has been & was never meant to be. This is why in mechanical situations where bolted together parts require accurate alignment, there is a pilot.

In short, it seems to me your tap is cutting threads deeper than your pin's threads, giving room for slop. It's tough to describe but very simple stuff & often overlooked. VERY common problem. Point being, if you want your shaft to fit flush to the butt, then you need to be sure your joint has a way of aligning the two parts to come together on center. A standard 3/8-10 with tapped holes simply doesn't offer that.

I Build the butts of my cues & have them prepped for finish before I even choose shafts for it. I make the shafts & then shave them down to the matching diameter of the butt. They always fit flush. Often, the shafts never get screwed onto the butt until the cue is finished & ready to ship. It's because my joint system is so repeatable & accurate. I use a flat minor pin that has a .3115" minor and it fits a hole that gets reamed to .312". It fits too tight to screw together so I have to coat the internal threads of the shaft with a lube. Then it fits smooth and feels snug but right as you are putting the cue together. I have my pins made to match my tooling exactly, and finish arbors to match my pins exactly. I struggled with the same issue you are having for a while. It sucks. But it's not necessarily you or the machine screwing it up. It's the nature of v-groove threads cut with a tap. To be honest, the fix will cost you quite a bit. Or you could try using Radial pins & tap and follow the directions exact. That'll get you a really good fit without costing much.

Otherwise you can accept the slop of your fit and roll with it. Screw the shaft on snug and chuck up the assembled cue, then shave/sand the joint area until the shaft & butt are concentric. Seems to be what a lot of folks do but it's just putting lipstick on a pig. Much better if everything fits right every time, every step of the way. Feels better, too, knowing it's right. Truth is that the difference likely doesn't affect playability, but if you take short cuts here then where else do you take short cuts? Multiple short cuts in a cue will certainly have the potential to affect playability, and longevity.
 
snipershot said:
Well, I don't have a small enough boring bar to bore a 5/16 hole. I'm very limited on options with my lathe, hehe. I'm looking for a metal lathe, but I was hoping I could still do some work with mine.

Joe
Click to expand...

you have to learn to bore using any lathe, it is part of the process of good machining.

bill
 
qbilder said:
Your holes can be dead nuts center, and threads cut dead nuts center to the holes, and still get .0025" runout on the pin, especially if you are bottoming out the pin. There's at least that much slop in the grooves of the threads. You can avoid it by using flat minor style threads, or else grind the threads instead of tapping and cut them to match the OD of the pin, to avoid settling to one side or the other. Otherwise, just a v-groove pin & tapped hole is not good enough for accuracy. Never has been & was never meant to be. This is why in mechanical situations where bolted together parts require accurate alignment, there is a pilot.

In short, it seems to me your tap is cutting threads deeper than your pin's threads, giving room for slop. It's tough to describe but very simple stuff & often overlooked. VERY common problem. Point being, if you want your shaft to fit flush to the butt, then you need to be sure your joint has a way of aligning the two parts to come together on center. A standard 3/8-10 with tapped holes simply doesn't offer that.

I Build the butts of my cues & have them prepped for finish before I even choose shafts for it. I make the shafts & then shave them down to the matching diameter of the butt. They always fit flush. Often, the shafts never get screwed onto the butt until the cue is finished & ready to ship. It's because my joint system is so repeatable & accurate. I use a flat minor pin that has a .3115" minor and it fits a hole that gets reamed to .312". It fits too tight to screw together so I have to coat the internal threads of the shaft with a lube. Then it fits smooth and feels snug but right as you are putting the cue together. I have my pins made to match my tooling exactly, and finish arbors to match my pins exactly. I struggled with the same issue you are having for a while. It sucks. But it's not necessarily you or the machine screwing it up. It's the nature of v-groove threads cut with a tap. To be honest, the fix will cost you quite a bit. Or you could try using Radial pins & tap and follow the directions exact. That'll get you a really good fit without costing much.

Otherwise you can accept the slop of your fit and roll with it. Screw the shaft on snug and chuck up the assembled cue, then shave/sand the joint area until the shaft & butt are concentric. Seems to be what a lot of folks do but it's just putting lipstick on a pig. Much better if everything fits right every time, every step of the way. Feels better, too, knowing it's right. Truth is that the difference likely doesn't affect playability, but if you take short cuts here then where else do you take short cuts? Multiple short cuts in a cue will certainly have the potential to affect playability, and longevity.
Click to expand...

Hi,

All of your reasoning and methods described is spot on and is great advise. I also used to have problems until I got a repeatable method.

If your sanding on the joint when the cue is assembled, either your method or equipment needs some investigation.

Its a nice feeling to know it's right before you roll and put the cue together.

Rick G
 
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qbilder said:
Your holes can be dead nuts center, and threads cut dead nuts center to the holes, and still get .0025" runout on the pin, especially if you are bottoming out the pin. There's at least that much slop in the grooves of the threads. You can avoid it by using flat minor style threads, or else grind the threads instead of tapping and cut them to match the OD of the pin, to avoid settling to one side or the other. Otherwise, just a v-groove pin & tapped hole is not good enough for accuracy. Never has been & was never meant to be. This is why in mechanical situations where bolted together parts require accurate alignment, there is a pilot.

In short, it seems to me your tap is cutting threads deeper than your pin's threads, giving room for slop. It's tough to describe but very simple stuff & often overlooked. VERY common problem. Point being, if you want your shaft to fit flush to the butt, then you need to be sure your joint has a way of aligning the two parts to come together on center. A standard 3/8-10 with tapped holes simply doesn't offer that.

I Build the butts of my cues & have them prepped for finish before I even choose shafts for it. I make the shafts & then shave them down to the matching diameter of the butt. They always fit flush. Often, the shafts never get screwed onto the butt until the cue is finished & ready to ship. It's because my joint system is so repeatable & accurate. I use a flat minor pin that has a .3115" minor and it fits a hole that gets reamed to .312". It fits too tight to screw together so I have to coat the internal threads of the shaft with a lube. Then it fits smooth and feels snug but right as you are putting the cue together. I have my pins made to match my tooling exactly, and finish arbors to match my pins exactly. I struggled with the same issue you are having for a while. It sucks. But it's not necessarily you or the machine screwing it up. It's the nature of v-groove threads cut with a tap. To be honest, the fix will cost you quite a bit. Or you could try using Radial pins & tap and follow the directions exact. That'll get you a really good fit without costing much.

Otherwise you can accept the slop of your fit and roll with it. Screw the shaft on snug and chuck up the assembled cue, then shave/sand the joint area until the shaft & butt are concentric. Seems to be what a lot of folks do but it's just putting lipstick on a pig. Much better if everything fits right every time, every step of the way. Feels better, too, knowing it's right. Truth is that the difference likely doesn't affect playability, but if you take short cuts here then where else do you take short cuts? Multiple short cuts in a cue will certainly have the potential to affect playability, and longevity.
Click to expand...

Thanks for the info Eric. I am using a v groove tap, but I would prefer to use the flat minor threads like my carolina cue has. I have some of those pins, but where can I get a tap for that? I'm guessing that's only done on a threading lathe. I also have been bottoming out my pins, and I checked the runout on a pin before I glued it in last night and it had the same problem. I'm only making simple sneakys out of old house cues at the moment, but I'm wanting to learn it all. I'm not interested in short cuts that take away from the quality of my cues, I want to be as perfect as possible.

Joe
 
snipershot said:
Thanks for the info Eric. I am using a v groove tap, but I would prefer to use the flat minor threads like my carolina cue has. I have some of those pins, but where can I get a tap for that? I'm guessing that's only done on a threading lathe. I also have been bottoming out my pins, and I checked the runout on a pin before I glued it in last night and it had the same problem. I'm only making simple sneakys out of old house cues at the moment, but I'm wanting to learn it all. I'm not interested in short cuts that take away from the quality of my cues, I want to be as perfect as possible.

Joe
Click to expand...

Your tap should work just fine, but if you are going to use a tap, the piloted tap works best. If your pins have a .308 minor, then get the tap with a .308 pilot and drill/bore your hole to .308. That will ensure your threads are centerline with the hole and the pin cannot waver from center. Same with shafts. And NEVER bottom your pin. Leave a slight void, which fills with adhesive, anyway. Bottoming your pin causes it to cock to one side or the other because it can no longer continue moving linear. It takes almost no discernable pressure to cause it, either. Either way, when using flat thread pins, the hole should be no more than .001" larger than the flat diameter of the pin.

It would do you great service to mount a dial indicator on your lathe so you can measure the runout of the wood sticking out of the chuck. The chuck's runout doesn't really matter much so long as you can monkey the workpiece around to where it is spinning true. Having your chuck running true merely makes it easier to get the piece center & true. But what you want to indicate & have running true is the cue itself. Once it's running true, don't move it. Drill, bore, thread & face, all while it's running true. This will make your joint face concentric to your joint pin and you'll know everything is center.
 
qbilder said:
Your tap should work just fine, but if you are going to use a tap, the piloted tap works best. If your pins have a .308 minor, then get the tap with a .308 pilot and drill/bore your hole to .308. That will ensure your threads are centerline with the hole and the pin cannot waver from center. Same with shafts. And NEVER bottom your pin. Leave a slight void, which fills with adhesive, anyway. Bottoming your pin causes it to cock to one side or the other because it can no longer continue moving linear. It takes almost no discernable pressure to cause it, either. Either way, when using flat thread pins, the hole should be no more than .001" larger than the flat diameter of the pin.

It would do you great service to mount a dial indicator on your lathe so you can measure the runout of the wood sticking out of the chuck. The chuck's runout doesn't really matter much so long as you can monkey the workpiece around to where it is spinning true. Having your chuck running true merely makes it easier to get the piece center & true. But what you want to indicate & have running true is the cue itself. Once it's running true, don't move it. Drill, bore, thread & face, all while it's running true. This will make your joint face concentric to your joint pin and you'll know everything is center.
Click to expand...
I practiced last night and I actually did indicate the wood at the joint to see where I was off, and it had about .0035 runout on it. It might have actually been less, but my practice piece was very cheap wood with lots of sugar and minerals. It didn't get very smooth like it should have, so it might actually have been better. With the v groove pins can I make the hole a touch smaller before I tap it? Would that help seat the pin a little bit straighter?

Joe
 
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