Drilling non-square segmented blanks.

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TonyL

TonyL

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Hey Folks,

Now that I build a decent sled to cross cut some blanks into segment slices, how does one find the center or simply drill where the blank will be left with the maximum material all around the hole. My segments are square, but the blanks I used were not both 3/4 inches - they were supposed to be.

Is it just a matter of sanding to the point where it is as square as possible. I guess drilling and irregularly shaped blank is a better job for a drill press; not drilling on a lathe?

Thank you!
 
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Tony

I carefully find the center point of THE PATTERN on both ends and then carefully turn between to a cylinder. I try to get 80% or so of the circumfrence or better round. I want even support along my Nova pen jaws.


Note that for fragile blanks wrapping in gause and ca glue may be needed.
 
Tony I think this might help. When I drill antler blanks I find the center on both ends and make an indent. Then I match one indent with the live center and the other with the point of my drill bit (the drill bit is in the head stock). If you push the blank into the drill bit with the live center (half way then rotate the blank) you have drilled the center of your blank if your drill bit and live center match.
 
This is good, but I usually place my drill bit in the tail stock. I did not know that I can put my drill chuck in the head stock. I thought the head stock hold a chuck jaws that rotate and the tail stock holds the drill bit (not rotating), but advancing forward toward the blank and head stock. Please pm me your number and a good time to call you; I am sure I am missing something. Thanks!
 
Tony, I solved that problem by turning the blank between centers until round. I then put the blank in my chuck with pin jaws and drill on the lathe.

Dave
 
Drilling with the drill buck in the headstock and a live center in the tail stock sounds like a recipe for disaster and possible injury, in my opinion.
 
Dave. I turn between centers with bushings. I don't believe you mean that. Do you mean to place the irregularly shaped blank between my 60 degree drive center inserted into the headstock and the live center inserted into the tailstock with enough pressure to rotate and turn the blank? Sorry fOr such a dumb question. Thank you.
 
Tony; Without seeing how you glued your blanks together or what your pattern is, it is hard to give a surefire method of drilling. This is what I would do. Take a straight edge and draw a line from corner to corner on the tops and bottoms of your blank. where these to lines intersect will be the center of your blank on each end. Mount your blank in the lathe and use a center drlll to start a hole at this intersection. Turn the blank around and do the same at the other end. Mount your blank between centers and turn round. Now you can drill your hole on the lathe or in the drill press. TIP !! Next time you do segmenting, drill your blanks first, cut to size, and glue together on the tube you are going to use for the pen. Everything will be lined up for you. If you are doing brick work segmenting, this realy helps to get your lines and angles aligned. You could also use a disk or belt sander to even out your blanks before drilling and bring them to equal sizes. The two centers on the lathe is a much safer way of doing it !! Jim S
 
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Thank you Jim (and all). I will take a picture tomorrow. It's just my third attempt at segmenting. It's about 10 cross cuts with alternating solid blue acrylic (about 5/8 inch each) and solid white acrylic (about 1/4 inch each) stacked on top of each other about 6 inches high in total. I will probably make a Rollester with it. I don't understand how to turn between centers with out bushings. I do have a collect system. Is it safe to put one end of the blank into to collect and turn it without anything on the tail stock end holding it?
 
Tony

Turning between centers is the spindle turning lingo for using a drive center in the headstock and a live center in the tailstock.

Pen turners adopted the term for use with bushings to contrast it with mandrell processes.

You should have a drive center that came with your lathe. Most have a point and 4 sharp edges that form a cross. I use steb centers most of the time for this.

If using a 60 degree live center, i suggest adding a small washer on the point to avoid splitting wedge action from the live center pushing into the blank.

The key is tofind where you want the center of the pattern so the resulting cylinder is concentric to the center line of the pattern.

This is one of the tricks of an excellent blank maker (RIP) known as Eagle.
 
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Thank you Ken. That's what I though,t but did not know that one can TBC without bushings or without a tube or hole in the blank, I have the steb drive center that came with my lathe as well as a 60 degree drive center. I also have a live center for my tail stock (60 degrees). I don't use a mandrel, only TBC with bushings. Thanks for clarifying. I wasn't sure I was hearing/interpreting correctly. Can't wait to give it a shot in a few hours!
 
Drilling an irregularly shaped segmented blank

Worked-out very well Ken considering the imperfectly sized cuts and alignment. Thank you. This was my third shot at segmenting anything. Here's the pics (try not to laugh....I am :) ).
 

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Thanks Ken. It was my first attempt to cut segments on a TS (with a jig, that since "perfected"). The jig and my skills were not quite up to par when I made these segments, so I just started gluing pieces together. I will use this to make a short single barrel pen. Thank for you help. Without the steb center, the blank just kept rotating. I would love to ask you a question or two live. I will PM you my number and leave that up to you. Best to you.
 
Tony, I use a clear ruler to line up the pattern. I use a punch on the end to mark center of pattern not center of blank. I turn round between a spur drive and 60 degree in tail stock.You use calipers to make sure it is the same diameter the whole length. I then wrap the blank in packing tape to help hold together. You can add a small block or leave a little long to prevent the drill from blowing out the bottom. Put drill chuck in tail stock and drill slowly clean out often. Perfect hole centered. Let me know if you have any questions. I can take pictures on the next one I make.

Dave
 
see.. EXACTLY why I love this group. Always willing to help someone learn how to accomplish something. I know I have learned so much. I have not done any "true" segmenting .. yet. I have done some quasi segmenting when I did the leather pen and also the steampunk pen. It is on the list though. :)
 
Can't beat the folks here! As I have mentioned in another post, I have opened my home to anyone that has informed me that they would be in the area (no one accepted yet..maybe I should be concerned LOL). I love the different opinions, even the different delivery styles.... I have never met such a selfless group (and I am a member of some very good faith-based groups that do o/s work for others). I love this site and the kind folks that comprise it. I am amazed by how the more experienced members to continue to help the less experienced. We are also blessed by some outstanding vendors!
 
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