Thread: Best way to cut various sized holes?

Hi and welcome.

You can buy adjustable spade bits for your drill, which may make it easier to cut to unusual sizes. Search on this and see what you get. "adjustable spade drill bits in australia"

Regards,

Rob

Originally Posted by blue

Hi all,

I have recently got into woodworking in the form of making jewellery such as rings, bracelets, earrings etc

My question is in regards to creating various sized holes for the rings. What would be the best method to create holes from around 15mm to 20mm. The things im finding hard is for ring sizes I need lots of irregular sizes such as 15.7mm, 16.5mm, 17.2mm etc so I cant use specific drill bit sizes.

Would it be best to just use the closest drill bit and sand the rest out?

The only tools I am using at this stage are a dremel, drill bits, belt sander.

Thanks for any help

Buy a reasonable quality drill press (there are a few on e-bay) and then use one of these Adjustable Hole Cutter - Drill Bits - Tools also get a good quality set of hole saws.

If you use a WW lathe you can make any size you want by drilling to approx size and then turning the remainder.

I think any of the adjustable cutters will be too big for rings - maybe OK for bracelets. I'd go with either BobL's suggestion and use a lathe, or drill and sand. Probably best to use Forstner bits in a drill press.

Originally Posted by blue

The only tools I am using at this stage are a dremel, drill bits, belt sander.

I am with Alex. get a drill press and forstner bits. You can also get small drum sander attachments for your dremel.

Make sure you mark your circle on the material, drill in through the centre with the largest drill that will not quite make it big enough then sand out to the line with the drum sander.

Cheers

Doug

I have drilled holes to unusual sizes by doctoring spade bits. Practice on those cheap sets from the "Dollar Stores" or other Cheap Shops.
What I did was use a bit a little larger than the hole size I wanted and removed equal amounts off either side using a bench grinder.
I know from practice that it is easy to do, and will get you out of trouble. After experimenting on the cheap bits, you may elect to buy quality bits.

Regards Ned

I hate to say it, but this is where the imperial system shines: odd sizes.
5/8 = 15.88mm
21/32 = 16.67mm
11/16 = 17.46mm

Not the exact sizes you want, but pretty close. Imperial bits are readily available, so that might be the easiest way.
Conversion table here: CONVERSION CHART: FRACTION/DECIMAL/MILLIMETER

Tappered reamer from each side carving knife for the middle. You should get any size you need off of one reamer. You could use a dremel or similar for the middle you have to sand it anyway. You could also get a ring sizer like jewelers use file a grove in it and use it as a reamer. Just some suggestions.

I'll throw in another vote for a lathe... as I've made quite a few rings this way.

This method has the advantage that the blank only needs to be mounted once, so all operations (drilling out the ID, fine-tuning the ID, turning the OD, etc., etc.) are always correctly centred. Plus, as a bonus, you can turn out several differrently sized rings from the same blank in a relatively short time period.

However, our own wedding bands were made with only a hand-drill, a dove-tail saw and one heck of a lot of sand-paper. (The only tools I had access to at the time. )

So I guess it comes down to the questions of "how many do you want to make?" and "how accurate do they need to be?"