What is the best way to use an 85mm Forstner bit?

[Eric The Viking]

I might try the clutched core drill option just to finish it off by hand with the forstner and then see about investing in a pillar drill once this one is finished.

Hiding to nothing, I fear.

You've picked the hardest material (almost), and given this used to be a keel block, it's probably got all sorts of inclusions - grit, iron/steel filings, etc. All of which will wreck your Forstner bit (which must have been seriously expensive if it's a reasonable one at that diameter).

Another question in regards to this project. If I decide when making my next one (I have the other half to this keel block) that I want to cut through holes rather than blind, what is the best way to cut through at least 30cm of solid oak 85mm wide? I'm looking for time saving efficiency here if this is to be a commercially viable option.

I've been mulling over this. I wonder if a modified TCT core drill might do it.

You can easily get the depth that way, and the core shouldn't get too stuck (If it does, drive a few big woodscrews in, Mole grips and PULLLLL!). There are some very nice people at my local Leitz sharpening centre - You might find someone locally who can re-grind the tip profile to be more suitable for wood. You might also need to relieve the supporting steel cylinder: making U-shaped holes in it ahead of the tips, analogous to the gullets of a normal saw, to take the sawdust.

Advantages: deep enough for the whole through-cut, shouldn't clog as much as a normal holesaw (wider kerf), cleaner cut (if you get the tip/tooth profile and speed right), nice finish (clean up wth a Carroll drum sander).

Disadvantages: needs power and decent RPM (wider kerf), almost certainly a BIG drill press (for SAFETY as well as usability - it'll be one hill of a saw!), expensive because of the modifications (make at least two of them once you get a good design), slow if you can't eject the cores easily (you'll only find out in use).

I don't think cutting it in half and re-glueing back together is an option as it is so heavy, it weighs a ton.

It will work pretty well on a bandsaw with a resaw blade, BUT see comments about inclusions above - don't expect long blade life! Fettle the bandsaw, fit a sharp blade (from Tuff Saws - take Ian's advice on choice of blade) and go for it. [edit] Because of the look (you want to keep this, I assume), you might need a resaw frame/carriage too (make one), so that you can make the block slide smoothly in one axis to get a clean, straight cut (and probably for safety, too).

I see that there are long length wide diameter masonry core drill bits for brick/concrete walls but no wide diameter long length hole core drill bits for wood.

There's an obvious reason: nobody does it like that! Big holes are usually mortices and thus rectangular. That's why there are things like chain morticers for timber framing.

If you are doing this seriously, have a look at modifying TCT masonry holesaws. They may be getting harder to find as diamond ones are ubiquitous now (and far cheaper than when I bought mine, grrr.), but you ought to get something to suit.

I really am no expert, but I can't see how you can achieve this without a significant investment in custom tooling of some sort, and/or modifying the design to help you in construction. It's simply too unusual otherwise.

E.

Afterthought: It's a keel block - you must be near a shipyard! Are there any old shipwright's tools that might do it? I'm still struggling to think of a marine application that would need such a hole, but there might have been something. Perhaps that's worth a bit of research. Ask a question over in the Hand Tools section.

PPS: On getting the cores out: say you have six teeth on the saw. before you make the big hole, drill six relieving through-holes in the waste, touching the circumference (say half-inch diameter). They'll take a lot of the sawdust in use, making a faster and cleaner cut, and, once done, you should only need to align the holes with the saw tips, for the core to slide out easily. THIS WILL NOT SAFELY WORK WITH A HANDHELD DRILL. The vibration as the teeth drop into and out of the holes will be a killer. (perhaps make four holes first and the last two when you're almost through?).

 

[Spindle]

Hi

Thanks for posting the photo - it makes it so much easier to offer advice.

I'm sorry, but I don't see any better way to achieve this from solid than with a hole saw / core bit. If I had the stock and were making this I'd plank the stock on a band saw and assemble as a closed box with an internal divider to support the bottles - the wood would still look great and you could probably get two racks from one piece the size of the original solid one.

As Erik says, the wood will be full of sand which will accelerate wear on your forstner bit and if I had paid in excess for £200 for it I don't think I'd abuse it in this manner, certainly wouldn't use it cutting near the surface of the block.

A consideration for your original design - if the bottles only go in 150mm and the block is 300mm square, once 'loaded' with wine all of the weight of the bottles will be on one side of the block's centre of gravity, the block will be unstable and have a tendency to fall over on it's side unless it is restrained, (fixed to a wall or horizontal surface).

Regards Mick

 

[Green]

I think CHJ's suggestion at the start of the thread is the best way (hog most of it out with smaller bits and finish with the large one).

 

[marcros]

somebody inquired a while ago about wanting to put wine bottle sized holes in an oak beam. I dont know whether they completed the task, but I seem to remember they were planning to use a holesaw.

There may be more information online if you google "oak beam winerack", keel blocks must be a bit rarer!

 

[hansonread]

This may seem odd but could you not instead of holding the wine bottle by its base, instead hold it by its neck?
that way you only require a 35mm hole which could be a lot more easily drilled with a good quality auger bit and if really required the bottom could be flattened with a forsner.

Pretty much every design I have seen for wine bottle holders out of reclaimed wood use this method and I have seen hundreds of examples, I have even made one myself using green oak (which was no longer that green after sitting in my workshop for 5 years gathering dust)

As far as equipment goes, if planning on drilling this out with the auger bits, I use a Hilti TE30-C with a SDS chuck attachment. its slow speed but massive torque cuts through like butter and has the added safety of a clutch. You can pick them up off hilti when on offer for probably less than you paid for that massive drill bit!

https://www.google.co.uk/search?q=recla ... B736%3B981

Not mine, buy you get the idea.

 

[AndyT]

somebody inquired a while ago about wanting to put wine bottle sized holes in an oak beam. I dont know whether they completed the task, but I seem to remember they were planning to use a holesaw.

There may be more information online if you google "oak beam winerack", keel blocks must be a bit rarer!

Marcros is right - this question has come up before.

Have a look at these threads

https://www.ukworkshop.co.uk/forums/cutting-92mm-holes-through-6inches-of-oak-t60383.html
https://www.ukworkshop.co.uk/forums/cutting-a-3-hole-in-oak-t78415.html

and you will see that there are at least two firms making and selling "wine racks" made by drilling big holes in lumps of wood. Personally, I still think they are hideous, but they prove that it must be possible; this post https://www.ukworkshop.co.uk/forums/post856714.html#p856714 says that core drills are the answer for at least one commercial company.