Two problems I need help with

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FrankP

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Hello. I have two separate issues going on that are driving me crazy.

First. I am having the hardest time drilling in the center of my pen blanks. The hole starts out in the center, but exits way, way off. I checked my drill press for square and the bit and table are 90 degrees. I am using a 7mm pen bit. Not the fancy kind that does it in one pass, but a regular bit. I am drilling slowly and removing chips as I go. I am holding the pen blank in a machinists vise. The pen blank is square in the vise. I have tried a second bit as well as another drill press. I can't figure this out. Oh, and I did try soft woods and hardwoods, same problem.

My second problem is a lathe problem. I have a Delta 46-700. I have very bad wobble in the headstock. I opened the cover and see a pulley and some bearings. I am not sure what is causing the wobble. I bought the machine years ago, but never did much turning. I can't imagine the problem is from use.

Any suggestions on either of these problems will be greatly appreciated.
 
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walshjp17

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I recommend getting a dedicated drilling chuck -- PSI has one -- and drill on the lathe. I use a starting, centering bit with the drill chuck first and then drill out the blank. Since I started this regimen I have not had any off-center holes. YMMV.
 

randyrls

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My second problem is a lathe problem. I have a Delta 46-700. I have very bad wobble in the headstock. I opened the cover and see a pulley and some bearings. I am not sure what is causing the wobble. I bought the machine years ago, but never did much turning. I can't imagine the problem is from use.

Frank; Is the headstock itself wobbling? You may have gunk inside the head stock taper causing the wobble in your mandrel. The smallest bur or gall on either the mandrel, or head stock taper will cause endless problems.

Google your lathe manual on the net. Most manufacturers now post the manuals on-line.
 

FrankP

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Hi John. I thought about a chuck for the lathe, but until I get the wobble problem resolved, I will have the same problem as the drill press. Besides, there has to be a reason the blanks are so far off on the drill press.
 

frank123

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All kinds of thigs can calus off axis drilling, Some suggestions:

First be sure you have both ends of the bland exactly centered on the drill axis and not at an angle,

Be sure your drill point is exact, perfectly ground and sharpened so one flute does not engage the material even the tiniest amount earlier and drag it off center at the start of the bore. this causes problems on a regular basis ind is not readily apparent - if you have a accurate micrometer measure the entrance and exit diameters at several different and opposing places to see if they are exactly round, if not this is probably a problem. This is probably the most common reason for off axis deep holes, factory drill bits are high production things and the ones made first at machine set up and the ones at the end of a run can be quite different as wear occurs within whatever tolerances the manufacturer allows.

Use something to start the hole, a spotting drill (best) a short fat stubby drill bit made out of an old drill with only a very short part of the flutes left (second best), a center drill (third best) or better than all three use a four flute center cutting end mill of the same as the drill bit size to bore the first three quarters inch or so of the hole and give it a perfectly aligned start. The purpose of this is to prevent or minimize drill bit deflection.

A spotting drill has a slightly (1 - 2 degree) shallower angle and allows the drill bit to engage in dead center of the bore so one flute or the other or even both do not grab the edge first. A home made one using an old drill bit that is short and fat enough that it won't flex gives a total surface initial engagement and not just an edge engagement and a center drill allows the bit to engage on the edges first which won't matter much at all if the bit itself is perfectly ground. Using an endmill gives a perfect bore for some depth that is aligned with the drilling axis if you need an absolute critically aligned starting bore. An endmill will follow its axis and a drill bit can deflect from it.

Wobble would make me suspect bearing play. I'm not familiar with your lathe but some bearing can be adjusted and others need replacement (I'm thinking you are meaning side to side play by wobble and not end play)
 

PenMan1

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For problem 1, I suspect the drill bit. First, find a scrap of wood and do everything EXACTLY the same as you do now, EXCEPT use a different drill bit that will drill a hole without resetting the table.

The reason I suspect the bit is because 70 percent of the time dull or improperly sharpened drill bits cause one side to cut faster than the other. This makes the hole wander.

If the test using a new drill bit fails, try starting the hole with a centering bit to see if this helps.

For problem 2, I need more information. Does a mandrel in the Taper wobble? Or does a chuck or faceplate wobble? A photograph or a short video wouldl really be helpful as your description is not very specific.
 
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FrankP

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Thanks all for the suggestions. I am going in the shop now to try some of them. I will post video and photos later if problems still persist.
The wobble is very noticeable in the headstock. Especially if I put a threaded mandrel in it and not feed it through the tailstock. It is also noticeable if I put a bowl faceplate on it. I think my drilling problem may be cheap drill bits. They actually came with the mandrels and they are not brad point. I'll report back tonight.
 

jttheclockman

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The second problem is actually your first problem and until you fix it you will not be making any pens no matter how you drill. Second when you fix the lathe the first problem goes away when you buy some good equiopment such as a dedicated drilling chuck for your lathe and get rid of the brad point bits. Get rid of them. Get some good machine bits and as stated get a starter bit.

I will adress the drill press issue and unless you did all the necessary checks as far as the bit is 90 degrees to the table, there is no runout to your drill chuck, the table is flat. the blank is held exactly 90 degrees to the bit after the above were checked then you have a problem. If you are making slimlines and with that bit that is what you are doing then probably it does not matter if you are not drilling straight unless this is a designer blank. As suggested get better bits and start from there with the drill press and make sure all of the above checks out also and report back.
 

Smitty37

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I often had slimlines drill off center - it was usually somewhat related to the blank some woods were worse than others, secondly the speed that I drilled at and how often I cleared the chips made a difference. I started using pre-cut blanks bought in bulk and there were many different woods. Never really had a problem with bigger, hence stiffer drill bits so I think it's also related to the size of the bit.
 
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FrankP

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OK. I have figured out both problems and would like to share so that maybe it will help someone in the future. The first problem was caused by cheap drill bits. The 7mm bits came with my pen mandrel. Today I received in the mail a Colt Five Star Pen Drill I ordered. The cost was about twice the cost of a regular bit, but OMG, what a difference it made. It drilled fast and true. The exit hole was just as centered as the entrance hole. So I am sure that the two pen bits I had were not very good.

The lathe problem, no so good news. After taking the whole headstock assembly apart, it appears the headstock screw is bent. I was hoping it was the bearings but it wasn't. Unfortunately, the headstock screw is no longer available from Delta. So the only choice I had was to use a vise and a hammer. I was able to straighten it out a little bit. After putting it all back together, there is some wobble, but not as bad. By the way, taking the headstock assembly apart is not for the faint of heart.
While I can use the lathe on big pieces with no problems, smaller turnings will telegraph some imperfections due to being out of balance.

So, I think I will save my pennies and look into getting a midi lathe, maybe a Delta or a Jet. I'll ask for some recommendations in another post.

Again, thanks to those who replied with suggestions. Hopefully what I learned will help someone else.
 
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I would at least keep looking for that part. I am sure someone here will have suggestions for parts suppliers that may help. Keep an eye on this thread maybe someone will come up with something.
 

FrankP

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Did you look at ereplacementparts.com? Sometimes they have or can get parts that others don't seem to be able to get.

I did check them. I searched quite a few sites that sell Delta parts.
The part number is 434-08-385-0001 and its called the spindle shaft.
If I can't get the part, maybe I'll look around for a junker lathe that I can salvage the shaft from. Aside from the shaft, the lathe is in great condition.
 
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