In Praise of the Centre Bit.

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Cheshirechappie

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Some months ago, I 'invested' about £16 on a certain internet auction site, and in two seperate lots acquired a vintage 'sixpenny' brace and a selection of 32 brace bits. I've been doing a bit of cleaning and sharpening, and having a play about with them.

The bits consisted of several centre bits ranging from about 1/4" to 1", a handful of shell and nose bits, and a few countersinks (which I haven't really tested yet).

I can't say I'm all that impressed with the shell and nose bits. They cut a nice, clean hole, and work just as well if turned clockwise or anti-clockwise, but that hole's diameter may not relate to the bit size, nor might it be where you wanted the hole to start. My conclusion is that if you need smallish holes for (say) screw pilots or screw-shank clearance, a modern lip and spur bit, or even a jobber's twist drill, in an egg-beater hand drill will do a better job.

However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.

Hole quality is remarkably good. I think cleanliness of cut depends a bit on careful sharpening of the side spur, but all my centre bits cut pretty well dead on nominal size. I gather some can cut a bit oversize - maybe if the centre pilot is sharpened a bit off, they don't quite drill true.

Where a twist auger will score is in drilling deep holes. The centre bit can be made to go a little off-line if the brace is tilted a bit.

Another thing to note, in passing as it were, is how impressed I am with the sixpenny brace. It's such a simple little tool, but very effective. The bit holder is just a square tapered hole with a little thumbscrew to pinch the bit's taper and hold it, so changing bits is very quick indeed - much quicker than with the two-jaw screw chuck of the bigger brace. That said, it doesn't have the sweep or solidity of build to cope with bigger bits, but up to about 3/4" centre bits, I actually prefer it to the Stanley 10" ratchet brace.

So - if you have a brace, but haven't acquired any centre bits yet, go forth and grab a few. They can be picked up for very little on Ebay, and I'd imagine for virtually nothing at carboots. Sharpened up, a selection to hand in the workshop would be well worth while!
 
Since the original post, I've found this blogpost by Shannon Rodgers (The Renaissance Woodworker) which has an embedded video mostly about centre bits, but with some reference to other brace bits. It's about 23 minutes long, so it's quite comrehensive and informative. He details the sharpening of centre bits from about 13 minutes in.

http://www.renaissancewoodworker.com/center-bits/

I found that if I sharpened with a file, it helped a bit to finish with a fine slipstone. (The other thing I've discovered is that sharpening the larger bits is easy, but doing the tiny ones is like watchmaking!)
 
On the strength of this thread, I have just treated myself to a set of 9 centre bits on eBay so that I can try them out. 1/4" up to 1 1/4" should cover most of what I will need!
 
Marcros - would you be kind enough to post your impressions and experiences with them, once you've had a chance to give them a reasonable workout? It would be useful to know if my findings were reasonably typical or a lucky one-off!
 
Cheshirechappie":1jwt1fp0 said:
However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.

Hole quality is remarkably good. I think cleanliness of cut depends a bit on careful sharpening of the side spur, but all my centre bits cut pretty well dead on nominal size. I gather some can cut a bit oversize - maybe if the centre pilot is sharpened a bit off, they don't quite drill true.

The rate control is key - it also means you can take a fine "final cut" when drilling to excavate a cavity; it's very difficult to take "just a bit more" with a bit with a lead screw.

The other key point is the ease of access for proper sharpening, so (as you say) the side spur can be truly-polished-sharp (not just filed-sharp), leading to good hole quality.

BugBear
 
bugbear":1i49qd76 said:
Cheshirechappie":1i49qd76 said:
However, the centre bits were something of a revelation. For donkey's years, I've been using Jennings twist augers in the handbrace, and for holes up to about 3/4" they do a very fine job, but pushing one much bigger than that into hardwood is asking for a lot of grunt. Not so with the centre bits - a 1" centre bit will take out a nice, clean hole in beech without much strain in a 10" sweep brace. In softwood, it flies through. Even a 3/4" hole can be drilled through beech using the (7" sweep) sixpenny brace; with a Jennings auger, you need the 10" brace to turn it. One thing that helps with the centre bits is that you can control the rate of cut by how much you lean on the brace - the screw pitch of the twist auger pilots dictate their rate of feed, and all mine are a rather coarse pitch.

Hole quality is remarkably good. I think cleanliness of cut depends a bit on careful sharpening of the side spur, but all my centre bits cut pretty well dead on nominal size. I gather some can cut a bit oversize - maybe if the centre pilot is sharpened a bit off, they don't quite drill true.

The rate control is key - it also means you can take a fine "final cut" when drilling to excavate a cavity; it's very difficult to take "just a bit more" with a bit with a lead screw.

The other key point is the ease of access for proper sharpening, so (as you say) the side spur can be truly-polished-sharp (not just filed-sharp), leading to good hole quality.

BugBear

How do you go about achieving that level of sharpness? I noticed on the link to the Renaiscance Woodworker (provided above) that he justs uses a file. I guess that you have some specialist bit of sharpening kit in mind.
 
Andy Kev.":392apzga said:
How do you go about achieving that level of sharpness? I noticed on the link to the Renaiscance Woodworker (provided above) that he justs uses a file. I guess that you have some specialist bit of sharpening kit in mind.

Slip stones and/or SiC wrapped round dowels etc. Not (very) specialist, although not a 2x8 stone,I grant you.

BugBear
 
Andy Kev.":2zj402so said:
I suppose it's obvious, now that you say it! Particularly for the bigger sizes.

I find centre bits at their best around 3/8" - 1", so not too fiddly a job.

BugBear
 
Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:

http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html

Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.
 
Andy Kev.":2rxtxwyw said:
Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:

http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html

Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.


I have to admit that my only experience is with the old-type centre bits as shown by Shannon Rodgers on the Renaissance Woodworker video. I do have one of the newer sort as the Oldtools link, one of a batch of assorted bits from Ebay, but it's a poor rusty thing that I haven't cleaned up or tried out yet. It'll be interesting to hear impressions and experiences of the 'new' type centre bits.
 
Andy Kev.":20z8fcs2 said:
Inspired by this thread and in particular by Cheshire Chappie's link to the Renaiscance Woodworker on the subject, I have just taken delivery of five new (new old stock) centre bits from these chaps:

http://www.oldtools.co.uk/tools/Wm_Ridg ... e_Bit.html

Not cheap but not ruinous either and they are in good order. So now I've just got to order some slip stones as per Bugbear's advice and I should be in business.

Hmm. Those are really very different; the spur is very different (and harder to sharpen) and they do have a leadscrew.

BugBear
 
Those are the same as the ones that I bought- some were ridgeway some another pattern.

Are the ones by the OP and subsequently described by others more like a forstner bit? I have seen these on a blog for a brace but never seen any for sale or in person.
 
I have quite a 'selection' of bits including the centre bits CC described so well. I also have a set of bits as bought by Andy Kev and Marcros, made by Wm Ridgway. They are newer than the others; I'd guess at 1950s.
Maybe they were offered as more sophisticated than the old style but cheaper than full length auger bits?

Edit: Buck and Hickman listed them as 'new type centre bits' in 1935 and were still calling them that in 1953.
A couple of 1950s catalogues (Gardiner, Tyzack) call them 'fast cut' centre bits.
 
The bits I was referring to are like these, illustrated on Chris Schwarz's blog - http://blog.lostartpress.com/2010/09/07 ... d-1-rimer/ - and are the sort covered by the 'Renaissance Woodworker' video mentioned earlier in the thread.

I found all mine on Ebay, using the search term 'brace bits'. They don't seem to come up as graduated sets of old-type centre bits very often (though I have seen the occasional offering), but the odd larger one does crop up for sale individually. Mine were accumulated by buying vintage assortments; they come up quite frequently, often consisting of a few 'old' centre bits, a few shell and nose bits, a few countersinks and sometimes screwdriver bits (well worth having a few sizes, especially the larger ones!) and the odd rimer. You sometimes see a brace and a roll of bits; it's worth scrutinising the bits carefully, since such sets rarely sell for big money, so you can put together a useful assortment of bits (plus some less useful) for not very much, with the bonus that you get a storage roll and a couple of spare braces, too.
 
Cheshirechappie":2d2vo27b said:
The bits I was referring to are like these, illustrated on Chris Schwarz's blog - http://blog.lostartpress.com/2010/09/07 ... d-1-rimer/ - and are the sort covered by the 'Renaissance Woodworker' video mentioned earlier in the thread.

I found all mine on Ebay, using the search term 'brace bits'. They don't seem to come up as graduated sets of old-type centre bits very often (though I have seen the occasional offering), but the odd larger one does crop up for sale individually. Mine were accumulated by buying vintage assortments; they come up quite frequently, often consisting of a few 'old' centre bits, a few shell and nose bits, a few countersinks and sometimes screwdriver bits (well worth having a few sizes, especially the larger ones!) and the odd rimer. You sometimes see a brace and a roll of bits; it's worth scrutinising the bits carefully, since such sets rarely sell for big money, so you can put together a useful assortment of bits (plus some less useful) for not very much, with the bonus that you get a storage roll and a couple of spare braces, too.

I think it is noteworthy that (prior to the dominance of auger bits) sets of brace bits are invariably (IME) mixed in type, as you say. It implies that the buyers knew, understood and exploited the strengths and weaknesses of each type, and used them appropriately.

BugBear
 
The Ridgeway type (Oldtools) was standard issue in everybody's kit at 32mm (1 1/4") for Yale locks, so there are a lot of them about. It's still the fastest and easiest way to do it, hard or softwood makes no difference.
 
bugbear":23ng9b6r said:
......

I think it is noteworthy that (prior to the dominance of auger bits) sets of brace bits are invariably (IME) mixed in type, as you say. It implies that the buyers knew, understood and exploited the strengths and weaknesses of each type, and used them appropriately.

BugBear
More likely that they simply didn't throw away the redundant ones on the off chance that they might come in handy. When they come up for sale it is likely to be after the previous owner's lifetime of not throwing stuff away often enough!
I've got drawers full of screwdrivers, never thrown one away and every now and then it proves to be a good idea - sometimes using an old one in a sacrificial way - hitting it with a lump hammer etc.
 

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