how to drill perpendicular around circumference accurately?

[TimberNut]

Hi guys. any suggestions for the following?

I am turning an ornate candelabra. Too many hours so far, and I don't want to stuff up the next bit.

I have the central stem done, and some side 'arms' that are going to hold more tulip shaped candle holders. I have to drill into the central stem to be able to glue in the 'arms' that will radiate out from it. There are 4 of them, so i need holes at 0, 90,180, 270 degrees.

(refer to pathetic sketch i have attached :o )

I have an indexed head, so i can rotate and stop the piece accurately, but then all I can think is to use a hand drill to drill the holes.
The accuracy will depend on how level I can hold the drill I guess. Not good enough.
Another option is to drill holes using the drill press, but then rotating the job won't be exactly 90 degrees each time.

Any suggestions to ensure high accuracy?

[silentC]

Can you set up the tool rest, maybe clamp a block to it, so you can locate the hand drill. Once you have it in place, it's just a matter of rotating the headstock for each hole.

Speaking as a person who doesn't even have an indexed head :( so I'm sure there is a proper way.

[Wood Borer]

I am not a turner but I do recall seeing someone making a jig to fit a router and the jig is clamped above the lathe so it's centre line coincides with the centre line of the lathe. Perhaps a similar arrangement can be done for a drill.

[rodm]

Mark the workpice out on your lathe using the indexing head and then transfer you workpiece to your drill press to bore the holes.

[smidsy]

Would it not be possible to mount a bench size drill press on the lathe - the base of the drill press should have holes in it for bench mounting so you could use these to bolt the drill press to the lathe bed.
Make a template out that will fit over the work and sit on the bed with markings every 90 degrees. Drill the first hole and then put in a pin of some kind in so you can rotate the work and get it accurate with the template.
Just a few thoughts.
Cheers
Paul

[RETIRED]

Will post a photo tomorrow of how I do it. Simple when you know how. :D

[barnsey]

Ian,

My thoughts for what they are worth,

Use your indexing to mark out where the holes are to be - that way you get to chose where you want to put then, ie with the grain etc. ;)

Then remove the piece to the drill press and use a V-Block to hold the piece steady and your holes should be perfect. :)

If this makes no sense at all then contact me and I'll try and explain it more clearly :rolleyes:

Jamie

[TimberNut]

thanks guys for the input.

Always wanting to test my limits and always looking for more accurate ways to do the same thing.

Any pics / diagrams you guys want to post will be happily viewed.
I know I could get it close, but this piece kind of warrants 'exact'.

I'll post a piccy of it when I get it done.

[scooter]

What about one of those spring loaded drill attachments (about $20 at Bunnings I think) that help you drill perpendicular to the surface. Possible rig up above the piece in the lathe.

Sean

[Sturdee]

You could built a jig for your drill press.

All you need is a board to which you fix some cleats to keep the turned piece in place, fix it to the drillpress table and clamp the piece in place.

Drill your first hole right through. Then insert a dowel into the hole, ease the clamp a little bit and turn it till it is at 90 degrees to the drill bit, tighten the clamp and drill the second hole.

I made my jig using V-blocks instead of cleats. Practice a few times with scraps and in no time you will get the hang of it.

Sorry, no pictures as the camera is not available for a few days.


Peter.

[RETIRED]

Step 1: Mount a square bit of hardwood in the lathe that is long enough to reach from the bed to above the centre height. I use 45mm square.

Step 2: Measure height of tool post and subtract 5mm.

Step 3: Turn the timber down to the Diam. of the pool post. As you can see I use a spanner as a sizing tool. Make sure that you have a square edge where it goes to round. This ensures that it always locates in the same place.

Step 4: Remove the tool rest and test fit the timber in the post. If it doesn't fit, sand to size.

See next panel.

[RETIRED]

Step 5: Fit a Jacobs chuck into the headstock with the appropriate size drill.

Step 6: Use the tailstock without a centre to push the timber into the drill using one flat of the timber. This allows it to drill at right angles to the timber.

You now have a drill guide that is dead centre of the lathe and if your timber is square you just angle it to whatever angle you want. Ours are made of steel.

I hope this helps.

[TimberNut]

! damn easy when you know how!

I used your idea and am quite pleased with the result. This technique combined with an indexing head solves problem perfectly!

I have attached a picture of the (almost) finished product. several more light sandings and coats to go. should be ready by xmas! ;)

anyone else out there into spirals?

[RETIRED]

No probs, glad I could help.

Looks good.