Im having some trouble with getting the holes Ive drilled in the shaft and/ or the tapping straight. Ive checked my lathe and tail stock is aligned and height is level. The shaft is indicated in the chuck and seems to be runnig tru. When I drill my hole I start with a center drill and then follow with a 1/4 inch carbide bit and then bore the hole with a mini carbide boring bar. Then I tap the hole with a 3/8 10 tap. When I check the tapped hole with a pin I find a ton of runout. Im thinking its my tapping process. Maybe someone could give me some method that works accurately.
drilling and tapping shaft holes accurately
- Thread starter kiinstructor
- Start date
the final hole is .3125. Ive even used a letter L carbide drill which is .2900 before boring. The hole seems straight but the tapping must be off.macguy said:
I think thats the way to go. Spoke to my machininst friend and he said he can do it but the tap must be fixed on the tip. Has something to do with the initial bite into the wood. Does the radial tap center every time?dzcues said:
The size of the pilot hole is probably your biggest problem, it is too big. It should be around .275 to .279 which is about 9/32. If you look in a standard shop manual they will call for a .312 pilot hole for a 3/8 tap, but a 3/8 x 10 cue screw has a smaller root diameter then a common machine screw and needs a smaller pilot hole. With a hole as big as you are drilling the tap can wander around, the hole is too big to guide it. Also you will get a tighter fit, somewhat along the lines of a radial screw when the cue is screwed together. Hope this helpskiinstructor said:
I can see your point but Im afraid of chipping out the wood when I tap. Im not sure the minor diameter of the tap. Im going to try .2900. I have a carbide drill that size and will try that. I still believe that if I gring the tap with a .3125 pilot it should follow the hole.macguy said:
kiinstructor said:
That is still too big, just use a 9/32. Do some scrap pieces and I am sure you will find it will work perfectly. Also, if you grind a tap with a .312 pilot, it will tap straight but the hole is still too big for the design of the screw and you will have a sloppy fit at best. There should be no worry about chipping out the wood since you are going to practice on scrap till you have your methods down cold. Don't take my word for it give it a try and see how it works. You can also drill an undersized hole by like .015 and then fill it with a wood hardener. Once it has soaked in pour out the excess and let it dry. After a few hours put it back in the lathe and size and tap the finished hole. You will have really nice threads that will not chip out on you and give a nice tight fit.
Great advice, Macguy. I never try anything new, until I try it on old junk, a few times first.macguy said:
Tracy
Great, you have some very creative ideas. Im goint to try the 9/32 hole first. What type of wood hardener are you referring to. I get the idea about drilling the smaller hole and filling it ect but dont know what type of material your talking about. Just checked the minor diameter of my taps and they are about .272 to .275 so the 9/32 should work. Seeing as how youve tried it. I cant tell you how much I appreciate your help. This has been a real hassle for me seeing my pins wobble and my tapped holes in shafts being out of line. Thanks so much.macguy said:
I have used super glue to harden the wood like willie mentioned. It works for me, and makes nicer threads, but I'm interested to hear if there is something better for that Myself. Sounds like macguy's using something else.
I also underbore the hole. besides centering the tap better, It also makes the joint screw together alittle tighter, but makes for a nice hit, and feels more like a one piece cue IMO.
I do pretty much what your doing, but I start with a micro endmill, then center drill, drill slightly bigger again, then 1/4, then I have a reamer I use, drill larger again, then a larger reamer, then bore to size with a special tool I have for small holes before tapping.
On butts I tap out of the jaws, but on shafts I've been tapping out of My steady rest. Check to make sure the tap is centering in the hole well. When you run it up in there, If you see the tap wobbling, you might as well stop there, because It's not going in straight.
I have an issue sometimes when installing the pin, where even though My fit is good, after I tapped the pin, it would screw in fine dry, and run true before glueing. I like to use a slower setting epoxy, but with the pins, they seem to move somehow over the long drying time with me, and I can pickup a slight bit of runnout by the time it dries. Quick set will stay centered though. Well, I would just use quick set, but the heat created from the quick drying time, seems to make it brittle & harder in My opinion, and not what I want up in there.
I am not using a special tap or anything, just the ones you get from atlas, and It does not have a pilot grinded on it. Would be nice, but can be done without It.
I have best results when I try a scrap piece of the same material out before I begin, just to make sure I have my system down and working properly. Taps are tough to work with, but can get the job done. Seems like I actually have a harder time with 5/16 inserts then 3/8 threads.
Most of these guys have realized that grinding the threads is the way to go, me too, just not setup correctly for it yet Myself, but can't wait for the day when I am. Some are press fitting pins to avoid the problem. I will not make any comment on that except to say I think the bottom of a radial was meant to be threaded, so that is the way I would go about It even with those. I'm not saying the press fit won't hold up with a good glue, I just prefer to tap the bottom also to be safe. I do the same with the inserts designed that way. Good Luck with it. Greg
I also underbore the hole. besides centering the tap better, It also makes the joint screw together alittle tighter, but makes for a nice hit, and feels more like a one piece cue IMO.
I do pretty much what your doing, but I start with a micro endmill, then center drill, drill slightly bigger again, then 1/4, then I have a reamer I use, drill larger again, then a larger reamer, then bore to size with a special tool I have for small holes before tapping.
On butts I tap out of the jaws, but on shafts I've been tapping out of My steady rest. Check to make sure the tap is centering in the hole well. When you run it up in there, If you see the tap wobbling, you might as well stop there, because It's not going in straight.
I have an issue sometimes when installing the pin, where even though My fit is good, after I tapped the pin, it would screw in fine dry, and run true before glueing. I like to use a slower setting epoxy, but with the pins, they seem to move somehow over the long drying time with me, and I can pickup a slight bit of runnout by the time it dries. Quick set will stay centered though. Well, I would just use quick set, but the heat created from the quick drying time, seems to make it brittle & harder in My opinion, and not what I want up in there.
I am not using a special tap or anything, just the ones you get from atlas, and It does not have a pilot grinded on it. Would be nice, but can be done without It.
I have best results when I try a scrap piece of the same material out before I begin, just to make sure I have my system down and working properly. Taps are tough to work with, but can get the job done. Seems like I actually have a harder time with 5/16 inserts then 3/8 threads.
Most of these guys have realized that grinding the threads is the way to go, me too, just not setup correctly for it yet Myself, but can't wait for the day when I am. Some are press fitting pins to avoid the problem. I will not make any comment on that except to say I think the bottom of a radial was meant to be threaded, so that is the way I would go about It even with those. I'm not saying the press fit won't hold up with a good glue, I just prefer to tap the bottom also to be safe. I do the same with the inserts designed that way. Good Luck with it. Greg
kiinstructor said:
I encountered a similar problem before. I had a tap made with a pilot guide for 3/8-10 TPI. Another thing to make sure is that the other end of the shaft or butt is supported/centered at the rear with a rear chuck or steady rest for perfect alignment so when the pin goes in, it's in the same horizontal axis as the shaft/butt.
Another point which I don't think was mentioned is. Is the shaft actually being held straight when your doing this.
I do not know what others are using but I use these bars and they are very nice. The geometry is right and they cut very clean. http://www.truemade.com/boringbars.htm
I buy the longest bars in the larger sizes.
I buy the longest bars in the larger sizes.
I had a special carbide tool made. Its a 1/4 inch shank so I had to make an adapter for my boring holder. Anyway I can give you the name of the fellow who made them for me. There really reasonable. about 30 or 40 bucks. Im almost to the point where Im going to try to make internal threads with my router. I know that a whole different animal but I see some cuemakers are using this method and have great success. If anyone knows about this process or knows any sources, let me know.powerpool said:
powerpool said:
Well, actually nothing real special about what I use. Just what ever is at My disposal and does the best job. I often use tools sometimes, not intended for the way I am using them, but they sometimes work really well in other ways then their original intended use.
I actually have many things I use, but here is a picture with a couple of tools I use as mini boring bars for inserts or short pins. I have others, but they are mostly common boring bars. the 2 tools on the bottom of the pic I sometimes use to bore holes for inserts. Sometimes I will snug fit other parts with them because they cut really smooth, and I can make as fine of a cut as I need with them to get a perfect fit. Those 2 tools were used when I got them, and still very sharp. I have yet to have to regrind the edge on them, and they still cut very smoothly. Greg
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Finally a drilling and tapping method that works
First off, I want to thank all the cue artists that lended their views on my original post. I really appreciate how open and helpful cuemakers are with their knowledge. I have finally discovered a fool proof method for drilling and tapping (with a hand tap), that makes concentric and smooth holes with smooth threads that look as if they were cut with a trimmer. I have practiced this method on over 25 pieces of various woods and found it to work well on all. If anyone is interested in my system, I will be more than glad to help. I want to again express my appreciation all the cue artists who assisted me. This forum is top of the line. Sincerely Mark
First off, I want to thank all the cue artists that lended their views on my original post. I really appreciate how open and helpful cuemakers are with their knowledge. I have finally discovered a fool proof method for drilling and tapping (with a hand tap), that makes concentric and smooth holes with smooth threads that look as if they were cut with a trimmer. I have practiced this method on over 25 pieces of various woods and found it to work well on all. If anyone is interested in my system, I will be more than glad to help. I want to again express my appreciation all the cue artists who assisted me. This forum is top of the line. Sincerely Mark