Drilling holes

[Mike Novak]

I have been making tops lately. I decided to try some cross grain instead of end grain, so I’m using a dowel for the stem. Drill hole, insert stem. Should be easy, but the drill bit wobbles a bit as it starts to bite and the hole ends up crooked. Top is chucked into headstock. I make a small dimple with a detail gouge. Drill is chucked into the tailstock. I’m using a “regular “ drill bit. I tried drilling a pilot first using a smaller bit, but the smaller bit does the same thing.

What am I doing wrong?

 

[Andrew Walls]

Have you trued up the piece and is it square in the chuck? My only other thought would be to try a brad tipped bit since that would likely prevent the slipping.

Total newbie here, so someone may come along with better suggestions, just the first things that came to mind.

 

[Brian Gustin]

drill bit wants to follow the grain - especially with cross grain , it'll want to go into the softer areas of the wood, so it'll slip off center and wiggle here and there. May help if you used a small brad point bit (for wood boring) - perhaps a 1/8 inch, that'll get you a decent pilot hole that center of your regular bit may follow better. Even with flat work, got to be careful about drilling into wood, especially with ring porous varieties like Ash and Oak - Another way to do it may be if you had a drill guide that registers square against the wood (like a dowelling jig) which you could drill with lathe off?

 

[hockenbery]

1. I would drill the hole off the lathe on a drill press.
The turn the wide part and the handle separately
The wide part can be held with a cone live center or pressed on to a wooden pin turned on waste wood held in a chuck.

2. When I drill on the lathe I start the hole very slowly in an 1/8 inch back out in a 3/16 crack out. This tends to let the bit center.
Spur bits tend to wobble less than twist bits

 

[RichColvin]

I‘ve found that a freshly sharpened bit works better also.

 

[Monty Ivy]

Increase the spindle speed (2000 rpms or so) for the first 1/8". That should allow the hole to start clean, centered, and with no tearing. Then back down to 500 rpm or so for the remaining work.

 

[Lynn Dudenbostel]

Have you checked the alignment of the headstock with the tailstock?

 

[Vincent Vogel]

I use a drill center to start them if It's critical to keep it centered then go to a brad point bit.

 

[stu senator]

Have you checked the alignment of the headstock with the tailstock?

The center point tips may touch but are the axis (tapers) concentric?

Try rough turning the body, drilling the hole and inserting the pin then grabing the pin in a chuck and finish turning the complete top.

 

[Dean Center]

Drill chucks are also notorious for being inaccurate. Perhaps you've got a bad one.

 

[robo hippy]

One problem with side grain/bowl grain tops is that when you get to the handle on the top, they tend to break along the side grain. As for being off center, I got some Delrin rods at a plastic supply place, cut 1 inch or so long pieces, drilled the hole, epoxied it in place, and then turned the point/tip round. They seldom end up being perfectly centered. I had tried getting top points from a couple of places, and they always ended up a bit off center. I like bigger tops like the Gasing types from Malaysia. Some appear to be 10 or so inch diameter, and heavy cord is used to spin them. They tend to have metal points, and can spin in dirt for several minutes. Tub Luj is another variation that is used in a kind of shuttle board type game. Most finger tops won't spin for much more than a minute.

robo hippy

 

[Tom Gall]

@Mike Novak Not sure I understand your turning process.
Drill hole (DP or lathe) --- glue in dowel --- mount the dowel in chuck (i.e. spigot or collet chuck) --- turn (all will be concentric to the dowel).
You can also use an end grain block with a dowel (to save wood). Direction of the cut for the larger diameter will change but you will get the same result.

 

[Mike Novak]

Thanks for all the suggestions. Looks like I have a combination of problems.

Tom
The process I was using was to form the bottom/point of the top, including a small groove. Then flip it in the chuck, gripping the groove. Next I put a drill chuck into the tailstock and drilled a 6mm hole. Pressed a dowel into the hole and finished the dowel.

Dean
It appears that the taper shaft on my Jacobs chuck is bent. Runout about 0.010 shaft only. I inherited it, and it looks like a quality piece. Jacobs brand, made in Hartford ct. not a speck of rust on it. I’m going to look for a new taper shaft. I have a chuck with much less runout, but it’s old & rusty cheap brand.

Stu
I don’t think my tapers are concentric. Centers Points touch when I bring them together, but off by about 1/32 with tip of drill when it’s held in a good chuck. I don’t think it’s adjustable on my 12/16


Starting with a center drill, using my “good” chuck, and going very slow with high rpm for the start I can get good enough results.

Robo
I’m going to look into those other top types.