Riving/Cleaving/Froe/Bodger's Brake/Break

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby gavin » Wed Jun 13, 2012 6:54 am

trollwumple wrote: when you think about it a froe is just an elongated wedge with a handel on it.

No. At least, it should just be only an elongated or wide wedge.

It is a steerable wedge. :D :D
Of course, if you just strike the back of the froe blade to drive it in to the work, and you never moved the handle relative to the split, it would then be just a wedge.

But as you lift or lower the handle the split you begin to form moves in sympathy with your handle movement. This often allows precision splitting where you decide the final dimensions, and not the work.
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby trollwumple » Wed Jun 13, 2012 6:50 pm

Brian, I agree with your last points regarding wedging and I bow to your superior knowledge "I am not going to argue the point with someone who does this for a living, lol", however on looking at my 3 froes they are all wedge shaped ie. thicker at the back reducing to a thinner front, for want of a better description almost a flat triangular profile, sort of wedge shaped, lol. however the purpose as you rightly pointed out is not to wedge a piece of wood open, like Peter F. did with his log, its to split a piece of wood with you controlling the split, by levering up or pushing down on the haft so the split runs where you want it to.

Gavin I really love your description " a steerable wedge" I wish I had thought of that.

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Wed Jun 13, 2012 7:09 pm

I think of the froe as a leverage tool. I found it a little scary actually putting so much force on the tool - knowing that the handles can/do eventually break. It brought to mind the chap on the TV show World's Strongest Man (or similar) a few years ago whose arm broke spirally while arm wrestling. With those thoughts in mind, Brian's suggestion to use wedges on the bigger pieces makes a lot of sense to me and I plan to follow it. I already use old wedges (which I recently cleaned up and sharpened) for splitting big rounds for bowl blanks, so extending their use should not be a problem.

Coincidentally I was looking at some new wedges at the weekend (didn't realise they were so heavy, some weighed 7lb). Looking at my existing wedges I reckon my father & grandfather used a wedge until it got ropey, then got a new one to act as primary wedge & carried on using the old ones as secondary wedges - consequently they range from pretty good, through pretty worn, down through small and v. knackered.

Brian Williamson wrote:Like the Psychic Pig - no, really, it isn't.
...
:D Did you watch "Have I Got (a bit more) News for You" by any chance?

Your suggestion that anything over 6" is large and should probably be split makes sense to me. Which has some bearing on that other thread, How long should a froe BE?.
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby gavin » Wed Jun 13, 2012 8:28 pm

ToneWood wrote: Looking at my existing wedges I reckon my father & grandfather used a wedge until it got ropey, then got a new one to act as primary wedge & carried on using the old ones as secondary wedges - consequently they range from pretty good, through pretty worn, down through small and v. knackered.

Have you pictures of these ropey wedges? They coule be instructive.
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby Brian Williamson » Wed Jun 13, 2012 9:06 pm

trollwumple wrote:looking at my 3 froes they are all wedge shaped ie. thicker at the back reducing to a thinner front

will


I will happilly concede that any blade (be it Opinel, froe or genuine wedge) driven into a piece of wood exerts a wedging effect. I will also acknowledge that if a means can be found for driving it through said wood (ie, by pounding on both ends of a long blade), the wood in question can be split in two.

However, if you do that with a blade with a right-angled handle, you are not using a froe you are using a (skinny) wedge with a handle.

The two (wedge and froe) work differently. A wedge will exert an equal splitting force on both sides. In theory, if you drove a wedge into the centre of a perfect piece of wood, infinitely long, then the split would travel down the centre and, when it eventually reached the end, it would come out in the centre.

This would never happen with a froe. It is a leverage tool and the act of leverage exerts more force on one side than the other. Consequently, the split would either run out (if you kept levering in the same direction) or would zig-zag its way along as you levered one side or the other.

This probably sounds very pedantic, but it is important to realise that any act of levering will cause your split to change direction, and that the essence of good froe work is to anticipate rather than correct. To keep your zig-zagging as slight as possible.

It is equally important to realise that, although many tools can be made to perform a particular task, some are better suited to it than others.

And I go back to my original point (made someway back in this thread) that the froe is a misunderstood tool and often seems to be applied to jobs where it may not be ideal (no crime in that, if it works).

And yes, I was watching 'Have I got (a bit more) news for you'. And I do rather like Victoria Coren.

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Wed Jun 13, 2012 9:49 pm

gavin wrote:Have you pictures of these ropey wedges? They coule be instructive.
I'll see what I can do. One side of the top half of one of the longer wedges is entirely missing! They were all mushroomed badly, although I have remove that from 2 (or 3?) of them. One is very short, as if the top may have been worn away by extended periods of mushrooming (or perhaps it was just v. short?).

Brian Williamson wrote:...
And yes, I was watching 'Have I got (a bit more) news for you'. And I do rather like Victoria Coren.

Brian.
:) Ditto
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby trollwumple » Wed Jun 13, 2012 9:56 pm

Brian Wrote

The two (wedge and froe) work differently. A wedge will exert an equal splitting force on both sides. In theory, if you drove a wedge into the centre of a perfect piece of wood, infinitely long, when the split would travel down the centre and, when it eventually reached the end it would come out in the centre.

This would never happen with a froe. It is a leverage tool and the act of leverage exerts more force on one side than the other. Consequently, the split would either run out (if you kept levering in the same direction) or would zig-zag its way along as you levered one side or the other.

This probably sounds very pedantic, but it is important to realise that any act of levering will cause your split to change direction, and that the essence of good froe work is to anticipate rather than correct. To keep your zig-zagging as slight as possible.

It is equally important to realise that, although many tools can be made to perform a particular task, some are better suited to it than others.

And I go back to my original point (made someway back in this thread) that the froe is a misunderstood tool and often seems to be applied to jobs where it may not be ideal (no crime inthat, if it works).


Some very good information in the above quote.

Brian, perhaps you could do a sort of photo post on the use of froes and ask Voodooalpaca to include it in the new "Guides section", I will do one on splitting large wood with wedges as I have had some big sweet chestnut "2 to 3 foot Diameter" come down in a storm a few weeks ago.

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby Brian Williamson » Fri Jun 15, 2012 8:58 am

Trying to suit some action to my words, here are some photos:


mainbrake.JPG
mainbrake.JPG (28.86 KiB) Viewed 8911 times
This is my principal brake. It stands maybe 7' tall and will take about 5" - 6". Not in the round I hasten to say. That would be much too strong and would have been wedged into halves or possibly quarters. The top arm pivots so that I can reduce the 'throat' size for smaller work. It is free standing and can be moved out of the way. If I'm riving really awkward stuff I might tie the top, but usually not.






DSCN0213.JPG
DSCN0213.JPG (49.02 KiB) Viewed 8911 times
This is part of my slightly smaller second brake. It shows the little notches that help locate those irritating one eigth or one sixteenth sections that always want to tip over (if you're riving them tangentially).





3-legged brake.JPG
3-legged brake.JPG (51.41 KiB) Viewed 8911 times
The three legged brake. Again movable. It's an idea I appropriated from Trevor Austin (the last Rakemaker) though his was more sophisticated. I use it for very small section work (like laths) It may be slightly confusing because there seem to be three rails. The lowest of the three is not, in fact, part of the braking mechanism, which you can use in reverse as a drawknifing brake.





block brake.JPG
block brake.JPG (40.68 KiB) Viewed 8911 times
This is the block brake. Hopefully self-explanatory. Basically I'm levering back against the support of my knee. Very good for shingles. The crossed slots taper so they hold different thicknesses of wood more securely.





upriving.JPG
upriving.JPG (64.7 KiB) Viewed 8911 times
Upriving. Riving without turning the workpiece over. You can only really do this with smallish stuff, but it's a useful trick. You're just using your spare hand as a third bar on the brake to lever up against.





wedges.JPG
wedges.JPG (29.65 KiB) Viewed 8911 times
The section of some of my metal wedges. You need two or three fine 'lead' wedges to enable you to get get a split started. It's amazing how many times an oak log can spit out wedges before you get the split established. Even with smaller sectioned, softer wood a well ground edge to a wedge is well worth the trouble. Think of them as just another edged tool. And make sure that you have twice as many wooden wedges (at least) as metal).





axecleave.JPG
axecleave.JPG (36.64 KiB) Viewed 8911 times
Finally finally, Using an axe to cleave a billet. This is a piece of semi-seasoned cherry, 8 1/2" across and 20" long and typical of how I'd go about cleaving small logs. Any longer and I'd have followed the axe with a small wedge into the side. Any wider and I'd probably have started with a wedge. I'd only have started with a froe if I wanted a dead straight split (cleft?) to start with - shingling for example. Or, of course, if the froe was to hand and the axe ten feet away! That by the way, is not the hatchet I usually use. I have a metal handled one picked up new at a County Show for £3. Very usefully, the poll is wider than the handle, so you can drive the head in all the way without the handle catching.

Hope there's something useful there.

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Fri Jun 15, 2012 1:36 pm

Brilliant post. V. interesting to see the various brakes used by an active professional. Lots of interesting nuggets of information too. That little notch is a good idea - I had just that problem at the weekend, one piece just wouldn't sit right, infuriating! Splitting 5"/6" with wedges before froe splitting them. etc. That's a v. nice tripod brake - is the apex bolted together?

RE. the 3-legged "sign post" brake, it took me a while to work out the purpose of all the bits. If I understand correctly:
- of the 3rd/back leg it to support the top-rail, which acts as the "back-bar" that holds the workpiece down. (Or do you work from that side & place the work over that bar?)
- the bottom rails just help hold it all together, as your brake is moveable - so could be missed out if brake were instead driven into the ground (fixed).
- the top two front rails are the front of the brake, they probably taper together towards one end (but this is not obvious in the image) to hold the workpiece. The bottom of the 2 acts as the fulcrum for the workpiece.

The "brake-block" is clever. Previously I thought you were proposing a log place horizontally on the ground, like the Japanese Craftsman featured on Peter Follansbee's riving page. This is quite different. Your froe looks quite small - but perhaps due to camera/perspective.

Think I'll leave the upriving technique to the experts -I'd surely loose my hand or thumb. Coincidentally this week a SA spearo showed me a technique that they use to brake a loaded speargun by gripping the tensioned rubbers & barrel with one's hand, in order to shoot into a confined area (hole/cave/wreck) - I figured he was trying to maim me too :D; actually its a good, advanced technique but there are several caveats that must be adhered to, to avoid serious injury.

Glad you explained about the axe in the last image. I've seen video on youtube of people splitting large logs, using (a wooden handled) axe as a wedge and hitting it with a wooden froe mallet/commander/beatle/beetle/... Seemed like a bad idea to me (although I have done it myself in the past) - and Granfor Bruk's axe book points out that only one of their axes is designed for this (one of the splitting mauls I think). I recently bought an old axe head (#1 Kent pattern) off ebay and it had clearly been damaged by being struck on the poll - it's quite a small light head (just over 1lb), so a particularly poor choice of axe to hit :(. I'm thinking my big (8lb?) splitting maul is probably designed to handle being hit with a wooden mallet but haven't tried it.

I'd never heard of sharpening splitting wedges until I saw the incredibly expensive Granfor Bruks ones - but I put that down to the Swedes being completely obsessed with sharpening everything to razor sharpness :D. jrccaim & Gavin convinced me otherwise and I must say it does help to have at least one or two sharp wedges. Not least to avoid having to (ab)use an axe, as described above. I've already discovered the benefit of making/keeping a few (usually larger) wooden wedges around - I originally did this intending to use them as inexpensive, chainsaw-safe, felling wedges. Sometimes a bigger round piece of wood is necessary/handy too - when the split it too wide for a metal wedge or to use as a drift, to reach the metal wedge at the bottom of a deep split.
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby Brian Williamson » Fri Jun 15, 2012 3:09 pm

Sorry, Tonewood, the 'signpost' is a complete red herring. And what's clear to me as the maker/user is merely confusing to the observer. I'll try to explain:

3-legged brake.JPG
3-legged brake.JPG (51.41 KiB) Viewed 8898 times

There are three, vertical posts/legs. The front two hold the main business end of the brake, the back one gives it stability. They are joined by an assortment of horizontal rails and diagonal braces.

Across the front two legs are four more or less horizontal rails. This is basically what you are looking at in the picture.

The bottom rail is merely part of the construction of the brake.

The next one up is used to support rake heads when I am drilling them.It is horizontal. It plays no part in the actual brake.

The third one is the lowest of the two brake rails. It''s angled up slightly from right to left and notched and nailed to the front of the posts.

The fourth one up (which is actually morticed through the legs) is the top rail of the brake. It is horizontal, so there is a very slight opening-out effect, but this is minimal as I use it now mostly for very thin stuff like laths and shingles. The 'signpost' effect is merely because it is too long and I've not got round to cutting it off! It is a replacement for the original which was notched and nailed to the back of the leg. I wanted to close the gap between the two rails to help with fine work (it didn't make much difference).

If you approach the brake from the back, you can put rake handles and similar through the two brake rails and 'spring'it up so it sits on top of the back leg. Holds it firm for drawknifing.

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Fri Jun 15, 2012 7:03 pm

Oh, I see, all is clear now. [When I wrote "sign-post", I was thinking of a 2-post sign |====| rather than a pointing sign |=== > -- I see what you mean though]

BTW I see some woodsmen use copper nails (for hurdles/gates/etc.). Are they just an old fashion corrosion-resistant predecessor of galvanised nails, or do they have some additional benefit for green wood work?
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby Brian Williamson » Sat Jun 16, 2012 7:04 am

ToneWood wrote:
BTW I see some woodsmen use copper nails (for hurdles/gates/etc.). Are they just an old fashion corrosion-resistant predecessor of galvanised nails, or do they have some additional benefit for green wood work?


I would guess that you're seeing this on modern work rather than old stuff in museums etc? I would guess also that it occurs mostly in conjunction with oak or sweet chestnut?

Mild steel and oak/sweet chestnut is not a good combination. The corrosive effects of the tannic acids can quickly eat small fastenings completely away and severely damage larger ones. Hence galvanised fastenings are commonly used (preferably hot-dipped) in modern day work. Galvanising would have been a product of the Industrial Revolution so is a relatively modern phenomona in itself.

In anything other than oak/sweet chestnut, a mild steel fastening would probably out-last the wood, so any form of protetion would have been unnecessary.

However (and the metal workers on this forum will correct me if I am wrong) mild steel was also (in practice) a product of the industrial revolution, and what would have been used before galvanising would have been wrought iron. Which is considerably more corrosion resistant than mild steel.

Copper would last (effectively) for ever in wood, but since wrought iron would generally last long enough and copper would have been more expensive it was probably never used. There were almost certainly cases where copper was used for decorative effect (rather like the copper-work you occasionaly see on roofs), but the generality, I'm sure, was no, it wasn't used.

Boat and shipbuilding is a different matter and copper (also brass and bronze) has been widely used because of its high resistance to corrosion.

So, if you see copper being used nowadays it's almost certainly for decorative effect. It looks good when new, but takes on that lovely green patina with age. Stainless steel is a good alternative in terms of corrosion resistance, but prople generally don't like seeing shiny nail heads!

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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Sat Jun 16, 2012 8:11 am

Interesting. Yes, it was in oak hurdles that I saw this. I have galvanized nails left over from a shed I built, gosh, 10 years ago, sound like they will be more than adequate for my "riven-ash hurdle-style garden trellis" (even if I succeed in making this, judging by the wind gusting through this morning, I'm not sure how long it will stand).
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Mon Jun 18, 2012 7:53 pm

[Added image on P1 of my first improvised pallet brake & steps - the poles were 8 foot long. And another image on P2 of the Ys-brake.]
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Re: Riving/Cleaving/Froe/Bodger's Brake/Break

Postby ToneWood » Wed Jun 20, 2012 12:48 pm

gavin wrote:
ToneWood wrote: Looking at my existing wedges I reckon my father & grandfather used a wedge until it got ropey, then got a new one to act as primary wedge & carried on using the old ones as secondary wedges - consequently they range from pretty good, through pretty worn, down through small and v. knackered.

Have you pictures of these ropey wedges? They could be instructive.

Here they are Gavin
Splitting wedges - 1.jpg
Splitting wedges - 1.jpg (73.02 KiB) Viewed 8840 times
Small wedge.jpg
Small wedge.jpg (45.09 KiB) Viewed 8822 times

Screwdriver shown for scale.

1. Middle-left is my primary wedge & quite sharp. A lot of mushrooming was removed with files & cold chisel. The edge is quite square & sharp but no where near Swedish-sharp.

2. Middle-right is my secondary wedge (although I often use wooden wedges/bars after the primary). Again, a lot of mushrooming was removed with files & cold chisel. I deliberately choose to show the worst side, the head is level but quite flaky around that void, top-middle. Reasonably sharp and even.

3. Right - just found this in my shed, didn't realise I had it. Seems a bit too small to be much use - perhaps will be useful when the wood is just a bit too big for the froe? Fairly blunt. Mushroomed.

4. Left, this one is in a pretty awful state, the top, front-most quarter is entirely missing! Mushroomed. The cutting edge is quite sharp but not at all straight - which makes it horrible to use, so I don't.

5. Stubby wedge also has a chunk missing from one side & bad mushrooming.

I wonder how old these wedges are and how many generations of my family might have used them? (4 definitely. I suspect several more - certainly by the state of them :D).
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