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Cutting accuracy, especially angles. How accurate really?

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Anonymous

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I was prompted to think about how accurate I cut after reading the 90 degrees topic, especially as that topic talked about a 5" board which is typical of the size I use most.

Now, I've never used a shooting board in my life - wouldn't know how to - but the only time I have any problems with accuracy is cutting odd angles. 45 degrees isn't a problem, nor is 90, but inbetween is tough. I usually cut as close as I can leaving a little spare wood. Then I dry-fit the pieces and if they are correct I can trim the spare, or if they're off I can adjust, because I've got a bit of spare to play with. Measure three times, cut twice.

That said, how accurate do you really need to be? Over a few feet (eg a table top) a fraction out can show badly, but over a few inches the natural movement in the wood is going to create more problems than cutting everything spot on isn't it? For my smaller pieces I have found that if I cut plus or minus half a degree then I can't see any difference. Only when it goes out by a full degree do I start to see anything and have problems.

Case in point... I've almost completed the jewelry box for my grand-daughter's birthday. It's 8.5" deep by 13" wide by 18" tall. I cut everything on the tablesaw and the only bits I planed were the drawers -- I made them all fractionally large and then planed them to fit the spaces. By the time everything has been sanded (100, then 220 and finished with 0000 after light varnishing) you can't tell if any of the joints weren't cut perfectly. I'm no expert dovetail cutter (and all the drawers on this box were machine cut with my router) but even they look pretty good. I'll post some photos in the completed projects section later, including the build process - I remembered to take some photos this time!

One point on the tablesaw. I went to see just how accurate my mitre gauge is and I estimate that the slack in the slot is enough to allow about a quarter of a degree of movement at the blade. Consistency of use by the operator should mean all cuts have the same error. I miminise my error by having a wide board fastened to the mitre gauge - it's almost 18" wide. Safer than using a narrow mitre - and I know that if my fingers are on the wood where I've marked it they can't be in the track of the blade. I still like the bight red table inserts though...

I can see accuracy is essential when doing fine inlays or some of the fancier joints, but my experience with dovetails is that by the time the glue soaks into the wood any slight spaces soon disappear, and half a degree off over a 5" run is so small it can be rubbed out, or even in, with sandpaper during the finishing. Alternatively, if you're working by hand it's easy to compensate...

Enough rambling. I guess it boils down to whether you are going for functional (as I do) or a demonstration of just how accurate you can cut a piece of wood (fine technique)? I admire people who can do the latter, but as a hobbyist I go for quality that is at least as good as I can buy, otherwise why bother. I have done some work professioanlly - made some desks for a company in Cambridge, MA,, for example - and that was to my own quality standard. My comment to any client before I even start work is "If you don't like the result or it doesn't deliver what I said it would, don't pay me". No-one has ever not paid...
 

Shady

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Hmmm... Interesting topic, which should generate some 'intense' replies - I'm surprised no-one else has stuck their head above the parapet yet...

IMHO, it's not about 'showing off' your jointing skills - it's about doing all you can to minimise the potential for what I call 'error snowballing'. You know, you think 'that's close enough', or 'the clamps and screws'll pull that cupped board flat when I glue up'... Sure it probably is/they probably will, if no other operations are required on that board. but if you then try to cut accurate joints on the cupped board, or make a run of (say) 5 cabinets for a room, they suddenly all have slightly different diagonals, and none of the batch of shelves you made to fit in them fit, and there are no joints that you are confident are a good right angle to reference from.

FWIW, my take is almost exactly the opposite: given wood's habit of changing dimensions, I like to eliminate as much uncertainty as possible. I know when I'm confident in the stock preparation, because the whole process seems to get 'into the groove', and it goes quicker and sweeter from start to finish. If I find myself saying 'it'll do', it invariably, in my case, means 'oh no it won't matey - but you'll probably only come to the critical show stopper after resawing and rendering useless for all other purposes lots of expensive stock...' :roll:

That said, if you're producing work you're happy with, your 'eyeballing skills' are obviously better than mine, and good for you! I find that the actual assembly bit is a fraction of the time I spend planning, measuring and setting up tools, machines and jigs. That's the way it works for me.
 

Pete W

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Shady":29ey5prd said:
I'm surprised no-one else has stuck their head above the parapet yet...
Let's not underestimate the power of shame :oops:

I have two projects underway at the moment. One is a benchtop router table - I'm appalled by my efforts at hand-cut mortise-and-tenon joints.

The other (I can hardly bring myself to mention it) is about the simplest woodworking project I can imagine: an incredibly simple slab of wood that will (eventually, maybe) be a holder/stand/tray for tea lights - literally just a piece of squared wood with four holes for tea lights. I started it because I couldn't think of anything simpler and I was desparate to find something I could finish.

So far I've failed (dismally) to get anything approaching a square cut to any face, in any plane, whether by saw, plane or sandpaper :shock:. My only excuse, such as it is, is that I'm attempting to do everything neander-style. If I could master the simple art of cutting square, I'd be a much happier woodworker!
 

Shady

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lol - know what you mean Pete - there are days when I seriously find myself wanting to put a flat, straight and true sheet of wood on display in the living room, with a handy set square, straight edge and a pair of winding sticks next to it, and invite everyone who enters to marvel at it's dimensioned beauty.. :roll:

" But you don't understand the hours of painstaking effort that went into that - and look, if you tilt it back and forward just so in the light from the window, you can see the polished surface that tells you it's been finished with a plane, not sandpaper - how impressive is that??!! You could build anything with this piece of wood - er, but it wore me out getting this far in the process.."

Ah well - it's actually part of what I like about this game: the satisfaction to be gained from a fairly arcane skill when you know you're actually getting somewhere with it - but there are an awful lot of beautiful bits of dimensioned scrap knocking around in my shop...
 
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Anonymous

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Let's not underestimate the power of shame
True, but learning from our mistakes is a major part of life experience, and not just woodworking. I have made my share, and some of them are in my scrap box, and I've even repeated some (how many of us haven't at some time?). I have miscut stock, had it jump because it wasn't held securely etc etc, but in the end it's still a pice of stock, albeit smaller. It's amazing how many 'problems' can be concealed by design -- and how many problems are created by design too.

'eyeballing skills'
I actually do have very good eyeballing skills, which my wife uses to her advantage! Last night, for example, she asked me to square up an embroidered cushion cover she'd just finished so it could be ironed, and I got it square within 1/8" across the 18" diagonals - she measured it. I also make a lot of the mounts and frames for her art, a lot of which goes to good galleries. My eyeballing ability definitely has something to do with how I work - and makes shopping difficult at times!

There's nothing wrong with being a perfectionist, especially if a run of cabinets ends up showing uneven cracks, but I don't think that being perfectionistic (taking it to the extreme) is a good thing, perhaps other than when teaching difficult to master skills. I have my limits, and I know them, but I still experiment with new techniques. materials, designs, etc., and still make a good few mistakes. Life is a learning experience...

Perhaps we need a forum here on mistakes and how to avoid/correct them? I'm sure every member would have something to contribute!
 

Shady

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Funnily enough, I was thinking about a 'mistakes and lessons learned' sticky just the other day: we seem to have an honest and relatively sarcasm-free bunch here - it might be interesting.
 

devonwoody

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Well gentlemen.

No problem just take photgraphs of your work and correct any errors using your imaging software (to cover nasties at joints etc). :lol: :lol:

I bet some of them do it :lol: :lol: :lol:

Not me of course. :shock:
 

Philly

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Brian
Sorry, meant to reply to this earlier.
Accuracy is a pretty important factor in woodwork-thank god were not into engineering! As time goes by and I improve as a ww'er, one of the main factors in this progress has been better marking out, and flat, square stock. This is a skill-making a piece of wood (which doesn't want to be flat) take on a reliable dimension (without wind) can only improve your joints, and therefore your finished item. Constantly having to bend and force parts together because they are not straight or square makes for projects that never quite go together right. (And I'm not talking about taking the odd shaving here or there)
Since buying my Tablesaw I have been able to easily get clean, square crosscuts. This makes life Soooooo much easier. I am a big fan of The New Yankee Workshop-I love watching Norm assemble his projects. Bang, bang-together they go, a real pleasure to watch and something I have been aspiring to.
Whilst I agree there is no need to go over the top when preparing timber, straight, square and wind free timber makes for better projects-end of story!
Hope this helps
Philly :D
 
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Yes, doesn't Norm make it look easy! Mind you, after 12 years since I first saw him most of my work is now in the same vein - measure, cut, bang, together! Practice makes perfect... The first jewelry box I ever made was for the wife - very simple, 3 drawers. Took me a week to make it. My latest project took less than 2 days, including glue-up, and it was far more complicated. Maybe I know what I'm doing now? - at last!!!

I agree with you on the flatness problem. I have some chunks of twisted stock lying around that will probably never be used, although small pieces cut from them often are. I don't have a surfacer, so can't get stock flat if it's too far gone. It's easier to go and buy another board! The usual problem for me is release of tension after resawing! That said, my work is often more in the 'artistic' category than in the 'perfect woodworking' category, so I make use of the imperfections from time to time. Sometimes I can 'flatten' twisted stock if it's thin enough simply by putting it on the bottom of the pile for a few months...

Recently I've been experimenting in art woodwork for the visually impaired/blind and that requires a total rethink on what you're used to so that they can get a good sense of what it is you've made. Traditional perfection simply doesn't do it -- don't smooth everything, don't have all joints flat, don't finish each surface equally, etc etc. Anyway, that's off subject...
 

beech1948

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Accuracy....I choose to throw money at the problem...I'm a lazy git you see. I also admire outstanding engineering as well. makes me a sucker for good kit.

I use a Felder combi CF741 as my hoby machine simply because it is accurate to a level other machines arn't. This provides confidence that any cut I make be it saw, planer, thicknesser or spindle will be spot on.

I of course being the human in all this still make the perfect cut in the wrong place..but shussshhhhhhhhhh :oops: :roll: :evil: :arrow:

There has been a marked increase in the quality of my finished projects since I acquired the Felder. I have found that stock can be prepared to thickness and squareness easily. Even boards with a bit of twist or bow or cup. I have become adept at taking sawn goods and removing a minimum of material and being able to use my starret square to find them all square...my winding sticks show that there is no visible twist.

My dovetails have increased accuracy and are more pleasing for being produced on square stock.

Not an advert for Felder just a statement that getting the most accurate piece of kit you can is vital. Treating it well, maintining it in excellent shape is also vital.
 

devonwoody

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By the comments above it is obvious that you have to be happy and confident with your tools. I think we must still remember they made some marvellous pieces of furniture 200 years ago without any use of machinery run on electricity. Mind you I would like a Felder. Anyone finished with theirs? :wink: :wink: :wink:
 

beech1948

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devonwoody":271n84wf said:
By the comments above it is obvious that you have to be happy and confident with your tools. I think we must still remember they made some marvellous pieces of furniture 200 years ago without any use of machinery run on electricity. Mind you I would like a Felder. Anyone finished with theirs? :wink: :wink: :wink:
devonwoody,
You may like a Felder but you ain'nt getting mine...what a wind up. Ironically, having got most of my machines to some level of tuning and accuracy I now find that for certain things hand tools are best.

I recently bought a Stanley 55 from ebay. If I need a 6ft length of stock to be moulded its quicker to use the 55 than reach for the router or use the spindle moulder by 50%...

I recently made a bench from structural pine 2x material a la Bob Key and tried to plane all of the sawn stuff to size by hand. Wow, aching arms, stock all slightly different sizes, some squarish some square. For the bench it made no difference but for finer stuff my hand skills are still not good enough. Keep on practicing....the off cuts bin is getting a bit empty as I try to practice my dovetails....in wierd combinations too...practiced on some mahogany scraps for tails and some pine for pins..ugh but good practice.

I find that accurate machines compensate for not having a high skill level to some degree and even better the compensate for not having an apprentice to do all the hard stuff.

Finally. My waistl;ine must decrease if I do much more hand work like planing to size.
 
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