Lathe troubles

[Snorton20]

I have a Jet variable speed mini lathe and this is the problem I am having. I am wanting to drill using my lathe however I am having a problem with the drill bit centering up and when I start into the blanks it starts to wobble and and wants to drill out of center. I have tried three bits with the same results in the same place as well. The photo will explain more about what I am getting. I hope you masters can give me an answer on what to do. Its almost as if the machines tail stock was not machined right dropping it down on one side. Has anyone else had this issue and what in the world can i do? Thank you

 

[wdcav1952]

Joe, my CarbaTec mini does not work well for drilling blanks with the lathe. There is a lot of slop when I advance the drill into the blank turning on the headstock. I don't know if I damaged the tailstock, or if it was that way when I bought it used. However, my Jet 1236 works quite well for drilling. It might be worthwhile to consider buying a new tailstock. Hopefully some Jet Mini owners will chime in with better information.

 

[low_48]

Joe, Do you have the tail stock locked to the lathe bed before you start drilling? Probably too simple of question, but I had to ask. You might also try to snug up the lock on the tail stock shaft just a little. Not so tight to lock it up, but just snug enough to keep it from vibrating.

 

[Snorton20]

The tail stock is in a locked position and I have also tried to tighten up on the advance lock down lever with no success. This lathe is less then a year old and was bought new at woodcraft. The box had no damage. I am thinking that maybe, just maybe the tail stock bottom was not milled correctly. I wonder if Jet will send me a new tail stock? I hope so. If anyone else could chime in with the info I gave this would greatly be a help. Thanks to all. Joe

 

[Nick]

I have been told and have tried this.
Using a Jacob chuck in the tailstock and a brad point drill in the jacob chuck, then advance the tailstock to the blank that is chucked in the headstock chuck, just till the point of the drill just touches the revolving wood blank. The drill in the jacob chuck will self center to the rotating blank, at that point tighten down the tailstock and begin drilling the blank. Hope this helps.
I guess my old age prevents me from putting my thoughts in printed form LOL.

 

[Snorton20]

Sorry Nick, I am a little confused. I have a lathe chuck which is not the most expensive one out there http://www.woodcraft.com/family.aspx?familyid=20042 and a drill chuck with a #2 MT that I paid a good amount for. It does not seem to be involving my headstock or the lathe chuck. Are you saying that I put a Jacob self centering chuck on the tail stock? Could you link the one that you are speaking of? Thanks

 

[Randy_]

All sorts of possibilities here. Pretty difficult to diagnose the problem from long distance.

Don't automatically eliminate the HS as a source of the problem. It might be that the scroll chuck (for any number of reasons) is not perfectly centering the blank.

I would check the TS quill to be sure it is absolutely clean before inserting the drill chuck. A tiny fragment of wood chip could cause the chuck to not seat accurately.

You might try drilling a centering hole in your blank using a small bit (maybe 1/8" dia.) to a depth of a half inch or a little less. Then install your brad point bit. With the lathe off, slide the TS up to the blank and align the tip of the bit as close as you can to the hole in the blank and then clamp the TS in position. The tip of the drill bit should be as close to the blank as possible without actually touching it. Turn on your lathe and set the speed to about 1500-2000 RPMs. Drill away and let us know what happens.

 

[rherrell]

It sounds to me that you have two things going here. First, I'll bet the drill bits you're using are "jobber" length. These are the most common and they are fairly long. Because of their length they tend to "flex". The simplest way around this is first: Insert them ALL the way in the chuck to reduce their length and second: Get yourself a set of these http://tinyurl.com/6ccotu
I use center drills EVERY time I drill on the lathe.
After you drill a center hole, if you're drilling a hole any larger than 1/4", do it in stages. For a 1/2" hole I use 3/16", 5/16" or 3/8" and then 1/2".
I also highly recommend "screw machine" length drill bits. These are about 1/3 shorter than jobber length and I use them almost exclusively on the lathe. Cut your blank in two before you drill and you won't need a long bit.
I also use these (can you tell I don't like off center holes?:biggrin http://tinyurl.com/6lp2ut
I bought these for drilling casings but now I use them on everything. A set of four, 1/4", 5/16", 3/8" and 1/2" will serve you well for making pens and you can get all four for $20.
At the very least try some center drills before you go spending money on new lathe parts.:wink:
Also, 1500-2000 rpm's is WAY too fast. 500-750 rpm's is where you want to be.
I also agree that you should tighten your tailstock lock slightly. Not so tight that it's difficult to move but you'll be able to tell when you have a slight drag on it and the slop is removed.

 

[Randy_]

Drilling Speed Chart


Rick is correct about the drilling speeds. I was thinking about twist drills when I suggested a drilling speed. For brad point bits the drilling speed should be slower.

Sorry.

 

[Jim15]

Joe I'm having the same problem with my Jet. I don't know the technical name but the part that holds my Jacobs chuck in the tail stock has play in it and when the drill bit first tries to enter the wood the whole assembly moves a little. I don't know how to solve the problem. This is the first time I have tried to drill on the lathe so I thought it was probably something I was doing or not doing correctly. I'll be watching with interest the suggestions the some of the more experienced people offer. Thanks for asking the question.

 

[rherrell]

Jim, as I said above, try tightening the tailstock lock until you feel some drag when cranking it forward. This should eliminate alot of the slop you're feeling. Just re-read your post. You said" the part that holds my Jacobs chuck in the tail stock has play in it". Are the tapers the same? I think your lathe uses a #2 MT so make sure your chuck has the same taper.

 

[brokenbit]

Have you tryed cutting a little hole in the end of blank with a chisle. this give the bit a place to start (Eagle's trick )

 

[randyrls]

I have a Jet variable speed mini lathe and this is the problem I am having. I am wanting to drill using my lathe however I am having a problem with the drill bit centering up and when I start into the blanks it starts to wobble and and wants to drill out of center.

Joe; I would not use a brad point bit. Tried them but didn't like the results.

The suggestion to drill in stages and use a centering bit are good ones for larger drill sizes. I would also mention that drill bits intended for metal tend to be better quality and more aggressive in cut. Drill bits also need to be sharpened from time to time.

The easiest way to check the lathe is to put a center in the headstock and bring the tail stock center up to it. When clamped, the two points should meet *EXACTLY* point to point. Then back off the tailstock and use the hand wheel to extend as far as possible. Bring the points together again. They should still meet EXACTLY point to point. This can also cause out of round mandrel alignment problems.

Metal lathes have a side to side adjustment on the tail stock so the tail stock is aligned with the head stock.

Hope this helps.....

 

[IPD_Mrs]

My first question would be how do your live and drive centers line up when you slide the tail stock up and you put them point to point? If those two line up and you have little to no problem drilling on a press then my guess would be the drill chuck is either not seated well or in many cases the cheaper ones seem to have a problem with the tapper aligning well. Make sure the tail stock tapper is completely clean. Use a flashlight if you need too.

Mike

 

[SamThePenMan]

I drilled blanks for a closed end pen the other day, on my PSI Turncrafter. The problem I have is my tail stock when loose can wobble back and forth off of center. I used a combination square to mark the center of the blank on the tail stock end, and then mounted the blank making sure the other end was flat against the base of my 4 jaw chuck. I then checked to make sure the blank was in fact centered by watching the center mark on the tail stock end of the blank as I turned it by hand, and under lathe power. Once I was satisfied that it centered and running true enough I slowly advanced the tail stock up to the blank making sure the drill center was on the center line. It wasn't perfect but I think it might have been more accurate than using a drill press. Only problem I had was that I was doing a small segment/laminate on this blank, and not having a table saw or band saw the two different woods were different sizes which made it a little more difficult when the 4jaw had to grab on to part of the blank that had the two different woods.

 

[IPD_Mrs]

Sam the easy way to fix that is to turn it to 3/4" round before you drill then use an ER-32 collet in the 3/4" size. Holds it very secure and you do not have to worry about centering it in the jaws!

Mike

 

[Randy_]

Jim, as I said above, try tightening the tailstock lock until you feel some drag when cranking it forward.....

Rick: I'm sure you meant to say tailstock spindle lock.

 

[RussFairfield]

You have discovered the problem with drilling deep holes into end grain on the lathe. There are 2 problems. Either the drill wants to follow the grain and there is no way to adjust the alignment after it has found its own place to start the hole, or there is a slight misalignment between the hand and tailstocks and there is no way to compensate for it. You can correct the first problem by making the drill start where you want, rather than letting it seek its own starting point. You can do this by making a starting hole in the center of the wood with the tip of a tool, buying a center-drill, or using a large (and stiffer) brad point bit with a center spur to make the starting hole.

There may be nothing you can do about it if the problem is a misalignment of the lathe.

Neither of these is a problem on the drill press because you can slide the vise around so the wood is centered under the drill.

 

[Randy_]

Sam the easy way to fix that is to turn it to 3/4" round before you drill then use an ER-32 collet in the 3/4" size. Holds it very secure and you do not have to worry about centering it in the jaws!

Mike: I agree completely that it would be best to turn the blank round before drilling, Not sure quite sure about the collet comment, though? Firstly, you are assuming the guy has a collet chuck which he very well may not. And secondly, it seems to me that if he has turned the blank round, the scroll chuck should hold it very accurately unless it (the chuck) is a complete junker.

 

[IPD_Mrs]

True Randy, but I was assuming that Sam was using a chuck that you moved each jaw separately and not the type that all the jaws move in unison keeping the stock centered. Well you know what they say about assuming. Anyway if you do not have a collet chuck it is well worth the investment, IMHO.

Mike

 

[txbob]

Joe,

This question is pretty basic, but just to be sure, do you have the wood mounted in the headstock and the drill bit in the tailstock? The wood spins and the drill bit doesn't? That's how it should be for drilling blanks on the lathe.

txbob

 

[gwilki]

Joe: I have the same lathe as you and don't have any problems drilling with it. You've gotten some conflicting info here, so I'll just tell you what works and what doesn't for me using a Jet Mini VS. Don't leave the tailstock loose and expect it to find the centre. It won't. On the Jet, if the tailstock is not tightened down, it can move off centre by quite a bit. Make sure the taper on your drill chuck is seated. If you've backed off the tailstock ram too far, the taper will be bottoming in the tail stock and the taper will not be seated. I use a centre drill to start all holes, but I don't then progress up a range of bits to get to the final size. Doing so takes away the ability of the bit to centre itself since the point of it no longer comes into play. Finally, after getting a dimple with the centre drill, be a bit aggressive when you start with the full bit. You want the tip to get in there quickly so that it centres the bit. YMMV. Good luck

 

[Snorton20]

I have the blank turned to 3/4" round and mounted in my lathe chuck. The tail stock is then moved forward to the point of where the bit is about a 1/16" away from the blank. Then I tighten the head stock down and then tighten up just a little on the quill lock down to get rid of some of the slop. Then I advance the bit into the blank and it starts to wobble as if it never started in the center. The photo I posted is the best I could do to explain what is happening and what it looks like. The seats are cleared in the quill where the drill chuck seats and everything is tightened on the headstock side. I guess I have no other way to explain it. What is going to disappoint me the most is going to be the fact that this is going to limit the amount of stuff I can do. I really want to start doing some segments and without this being figured out I think that it is going to hinder the quality of craftsmanship. It was said that it might be the drill is following the grain. It does not even start to wobble off the bat. The brad point starts to make a circle pattern not a dimple where you know it is centered. Oh well I will see if any of this helps you guys out. I will try to take a few more photos

As always thanks to all, Joe

 

[kirkfranks]

Joe,
I do think it sounds like an alignment problem which is what you suspect.
It would be worth a call to Jet and ask their opinion.
My PSI lathe has an alignment problem (slop) that can be seen.

One last thing to check since it has not already been asked. Have you checked to make sure that the drill bit is not bent? Since it is not spinning like in the drill press it would be easy to miss this. Try slowly rolling the drill bit on something perfectly flat like a piece of plate glass or cast iron saw table. Watch the point of the brad point to make sure that it does or does not stay centered.

 

[KenV]

Looks like the tail stock is not centered and the deviation from the true center is 1/2 of the little hole where the brad point bit is making a donut.

While you want slack out of the tail stock lock so it does not rattle around, it needs to be loose enough that the drill bit point will move the tailstock to self center. My jet midi has a few 1/16th of play and I have not spent the time fitting shims to make it more true.

This is not intuitive -- and the assumption that the tailstock is aligned with the headstock is probably not true unless you have specifically made it so. Probably close enough for wood work, but not if you lever down on the tail stock so it cannot move to find center.

P.S. Vertical alignment is the tough one -- lateral will work out with the side to side movement of a snug but movable tailstock.

 

[gwilki]

Joe: If you put a dead centre in the head stock and a live centre in the tail stock, then lock down the tail stock and advice the live centre, does it line up with the dead centre?

 

[Snorton20]

Joe: If you put a dead centre in the head stock and a live centre in the tail stock, then lock down the tail stock and advice the live centre, does it line up with the dead centre?

Yes, they line up. Also I did shift the tailstock to one side and this helped a little. Thanks to all that gave there input. I hope I get to do my first seg soon. Believe you me, you all will be the first one to see. Thanks again

 

[Randy_]

True Randy, but I was assuming that Sam was using a chuck that you moved each jaw separately and not the type that all the jaws move in unison keeping the stock centered. Well you know what they say about assuming. Anyway if you do not have a collet chuck it is well worth the investment, IMHO.Mike

No doubt about that, Mike. I don't use mine a lot; but when I use it nothing else will do!!

 

[Randy_]

.....The brad point starts to make a circle pattern not a dimple where you know it is centered. Oh well I will see if any of this helps you guys out. I will try to take a few more photos.....

Joe: I know you said you tried several drill bits with the same result so I have a question and a suggestion. Maybe you got an entire set of bradpoint bits that are ground off center? Is your set of bits a quality set or a $9.99 set from a discount tool place? Suggestion is to put one of the bits in a drill press and try drilling that way to see if you have a similar problem.

I have a JET mini and have no trouble drilling blanks so it can be done. I agree with the suggestion that a call to JET technicians is certainly in order. It may take some work and head-scratching; but it should be possible to solve this problem sooner or later. Hang in there!!

 

[Randy_]

.....My jet midi has a few 1/16th of play and I have not spent the time fitting shims to make it more true.....

Ken: Did you really mean to say that? Even only two 1/16s is 1/8" and it is very hard for me to believe a lathe could be out by that much or that you could shim it enough to correct such a misalignment.

 

[Snorton20]

Joe: I know you said you tried several drill bits with the same result so I have a question and a suggestion. Maybe you got an entire set of bradpoint bits that are ground off center? Is your set of bits a quality set or a $9.99 set from a discount tool place? Suggestion is to put one of the bits in a drill press and try drilling that way to see if you have a similar problem

The bits that I gat are like 6 dollars a peice for the 7mm ones. I have three that gave me the same result.