2" drill bit for a long hole.

fergal.b

Hi guys,any ideas on what type of drill bit I can use to drill the shaft hole in my boat, I will be using the strut as a guide to keep it dead center and at the right angle so it will look something like this



The hole will be quite deep as it will be going through the keel at about 13 degrees so I don't think a saw bit will work.



I also have to find a way to attach the bit to the shaft but I will worry about that when I get the bit.
So if you have any ideas on what type of 2" self cleaning bits are out there that would be great.
THANKS

William Powell

Looking at that I'd be setting up that "jig" on a test piece of timber with similar grain and boring that out to find out the problems well in advance of doing the real thing.

I think I'd also be clamping a shaped peice of wood over the entry area so the first thing the drill hits is a flat surface so it can start square.

fergal.b

Thanks William, I plan to have a block like this to start off the hole.



I will be drilling through two layers of 1/4 marine ply and 2" of mahogany plus the block so the hole will be quite long when it's at an angle any ideas on what type of 2" bit would be up to the job.

William Powell

tbh I'm not sure why your asking here as you look as if you know what your doing .

But opinions are free so heres mine. I've cut 18inch deep 3/4inch holes through solid oak for hanging field gates by hand using a bright scotch eyed auger, almost by definition they are 2ft long but 2inch is probably to big for that technology, I have 1inch augers and have seen 1 1/2 inch ones so think they are out. One advantage of the old bright scotch eyed auger was if you wanted a 4ft long one you just cut the handle off and weld on a couple of feet of bar plus the handle. http://www.fine-tools.com/bohr2.htm shows some pics of what I call a bright scotch eyed auger.

I'd be thinking of using a fostner bit but taking extra care not to get it stuck by doing just a inch at a time then withdrawing it, imagine if it snapped off 6inches into the hole :eek:. http://www.fine-tools.com/bohr4.htm has some suitable but very expensive bits with an extension which gives about 8 inches of drilling depth (not enough I'm sure).

I'd also be thinking that the outer shaft seems to be a standard size and may be I could put a cutting edge on one end and make the boring bit out of an old shaft casing?

The sort of block I'm on about is just to provide a starting point for whatever bit you use that is at right angles to the bit. I'd think about gluing and making it continuous with the hull so at no time the drill bit would be in a position of only having one side rubbing on the timber as it might as it started into the keel at an angle.

fergal.b

Thanks again, I'm asking here as I have never used or seen a 2" bit that will do this job and was hoping one of you guy's had, as for the drilling part I hope I know what I'm doing



That foster bit looks like it will work alright and it comes in a 2" for a price :eek: I had a look on the B&Q site to see if they had any and they had one of these still not cheep but I will pop down tomorrow and have a look at it "might work"

William Powell

afaik the advantage of those ridiculusly expensive bits is in the way they cut, clear the chips and (don't) heat up. Use a standard fostner bit for any lenght of time in hard wood and you'll start to see it burn as much as cut.

slowburner

William Powell wrote: »

tbh I'm not sure why your asking here as you look as if you know what your doing .

But opinions are free so heres mine. I've cut 18inch deep 3/4inch holes through solid oak for hanging field gates by hand using a bright scotch eyed auger, almost by definition they are 2ft long but 2inch is probably to big for that technology, I have 1inch augers and have seen 1 1/2 inch ones so think they are out. One advantage of the old bright scotch eyed auger was if you wanted a 4ft long one you just cut the handle off and weld on a couple of feet of bar plus the handle. http://www.fine-tools.com/bohr2.htm shows some pics of what I call a bright scotch eyed auger.

I'd be thinking of using a fostner bit but taking extra care not to get it stuck by doing just a inch at a time then withdrawing it, imagine if it snapped off 6inches into the hole :eek:. http://www.fine-tools.com/bohr4.htm has some suitable but very expensive bits with an extension which gives about 8 inches of drilling depth (not enough I'm sure).

I'd also be thinking that the outer shaft seems to be a standard size and may be I could put a cutting edge on one end and make the boring bit out of an old shaft casing?

The sort of block I'm on about is just to provide a starting point for whatever bit you use that is at right angles to the bit. I'd think about gluing and making it continuous with the hull so at no time the drill bit would be in a position of only having one side rubbing on the timber as it might as it started into the keel at an angle.

Sharpening a shaft seems to be a great idea - do you mean sharpen it to cut in the same way as a hole saw?

1chippy

mcquillans were selling a full set of stanley fostner bits for 59.95. up to 2 1/2 ". got a set. they hold there own but at that money you cant go wrong. you can have the two inch out of my set if you want. will be in your area in a couple of weeks. its not really much use to me. got another set a while back so have spares.
glad to see your movin along with your boat. still only cutting the frame on my own.

fergal.b

The shaft is only 1" and I need a 2" hole to fit a fiberglass tube in it to hold the stuffing box that will seal it up.

fergal.b

1chippy wrote: »

mcquillans were selling a full set of stanley fostner bits for 59.95. up to 2 1/2 ". got a set. they hold there own but at that money you cant go wrong. you can have the two inch out of my set if you want. will be in your area in a couple of weeks. its not really much use to me. got another set a while back so have spares.
glad to see your movin along with your boat. still only cutting the frame on my own.

Thanks for that your a star when I lenghten it and drill the hole you can have it back for yours.

slowburner

fergal.b wrote: »

The shaft is only 1" and I need a 2" hole to fit a fiberglass tube in it to hold the stuffing box that will seal it up.

Oh I understand . Looks like you're sorted now anyway. Great stuff.
It is such a pleasure to see this kind of helpfulness about - warms the cockles.
Let us know how it goes.:)

martin46585

You could use an ajustable auger bit, if I am right I think they will cut any size from 18mm to 65mm and everything in between, probably not as popular as they once were, though still readily available, couple this with an drill bit extension and it might just do your job.................

William Powell

martin46585 wrote: »

You could use an ajustable auger bit, if I am right I think they will cut any size from 18mm to 65mm and everything in between, probably not as popular as they once were, though still readily available, couple this with an drill bit extension and it might just do your job.................

Plenty of reasons I'd avoid an adjustable auger bit

1) not very good cutting with the grain
2) will wander off center
3) jam very easily in deep holes
4) generally get jammed up and stop cutting due to poor chip clearance
5) can't be started on an acute angle - but you could work around that easy enough

jack of all

I have an old Ridgeway adjustable auger bit myself and I think they are only really suitable for use in softwood. If the forstener bit doesn't work out you could try and source something from this crowd:

http://www.starminfo.com/export/aboutstarm.html

I have an adjustable "holesaw" from them, top quality stuff and not cheap.

fergal.b

Cheers guy's I will give it a go with 1chippy's bit and see how I get on with a test hole on some scrap wood first. One thing I don't like doing on boats is drilling holes in them
I will post a photo or video when it comes to doing it for real :eek:"if it comes out right":)

martin46585

William Powell wrote: »

Plenty of reasons I'd avoid an adjustable auger bit

1) not very good cutting with the grain
2) will wander off center
3) jam very easily in deep holes
4) generally get jammed up and stop cutting due to poor chip clearance
5) can't be started on an acute angle - but you could work around that easy enough

Are you having a laugh, the adjustable bit is no better or worst than any auger bit, except for a shorter flute to eject the chips, which if the bit is withdrew more often will not cause any trouble with jamming, as for wandering off centre and for #5 just what 2"bit can you start from an acute angle without the use of a sacrificial block of wood with the top edge perpendicular to the drill bit.....

slowburner

I find that augers wander off course and that they jam easily.

fergal.b

Thanks again 1chippy the bit worked fine

Drilled out the hole for the prop shaft , I had been putting it off a bit as there is no room for a mistake here.The angle was worked out from the engine setup and then marked on a bit of scrap wood where I drilled out a hole to take the extension bar holding the 2" bit, I also put a block of wood on the keel inside and out the same angle as the bit to give the tip a starting point and so it would not start walking when it came through.

All in all it went well except for the sawdust and smoke under the boat from drilling a 10" x 2" hole in mahogany while lying on your back , in the end it came out spot on target I now have to epoxy in a fiberglass tube to seal it up and then cut it down to size.

Double Barrel

A bit late to the drilling party but I like this builders thought process and set-up :

http://www.gartsideboats.com/faq/boring-long-holes.html

Good job Fergal.

slowburner

Double Barrel wrote: »

A bit late to the drilling party but I like this builders thought process and set-up :

http://www.gartsideboats.com/faq/boring-long-holes.html

Good job Fergal.

Clever set up.

fergal.b

Handy setup alright, a bit like him I also cut out some hardwood bearings with a hole saw and slid them over the extension bar allowing them to go into the hole and keep the shaft in line and at the right angle.

1chippy

Fair play fergal. I kinda regret not having one more on the boat. My workshop flooded a 5 or 6 weeks back. had 16.5 inches of water in. the boat would have been handy.

fergal.b

1chippy wrote: »

Fair play fergal. I kinda regret not having one more on the boat. My workshop flooded a 5 or 6 weeks back. had 16.5 inches of water in. the boat would have been handy.

Sorry to hear that :eek: your not having a very luck year hopefully next year will be better