What is a measurement?

[woodbloke]

Agreed Paul, and I remember we nattered at some length in you 'shop over fags and coffee on the best way to set them out. If you were to try and do that sort of thing and work it out on paper, it's quite a tricky technical drawing exercise to draw it out...it's the sort of thing that we used to do in the old TD lessons at school, but your solution clearly was the practical way to determine the angles - Rob

 

[Jacob]

..... It was a variation on the rod.......l

Not really. The rod is another thing altogether. For your table this is the "rod" way to do it: http://www.owdman.co.uk/howto/howto2.htm
Scarily complex at first glance but beautifully efficient once you have the knack.

 

[woodbloke]

For a chair you can of course measure.

Hallelujah and praise be \/ ...a breakthrough at last!...I can enjoy me glass of vino tonight :lol:
Now about those rounded bevels :lol: :lol: - Rob

I think you have missed the point as usual Rob so I wouldn't hit the bottle too soon!
I've got nothing against measuring - that'd be insane. The main point of the rod system is to eliminate error, where measuring is often the cause, especially the detailed addings and subtractings which go on once things get a even a bit complicated.

Jacob...sorry, read what you writ...'For a chair you can of course measure' - Rob

 

[Jacob]

[.....
Jacob...sorry, read what you writ...'For a chair you can of course measure' - Rob

Read it, wrote it, now read what I wrote!

 

[kirkpoore1]

The thing about measuring is that you have to know the accuracy you need and limitations of your tools. Thick rulers can introduce parallax, measuring tapes can have error in the end hooks, etc. Different rulers will disagree over longer distances. I'll use a tape to lay out cuts on a long board, but if I need it tight (say, within 1/16"), I'll measure mark to mark on the tape, not using the hook. Story sticks (rods) at least have the advantage that they'll change length with changing temperature at about the same rate as the wood you're going to use. I've never measured the difference in lenght of a long board over a large change in temperature, but it's certainly not trivial.

Direct comparison to full sized drawings is fine, but I'm not set up to make full sized drawings of, say, a 42" long blanket chest. Nor does it matter, really, if it's 41-7/8" long if the joints are tight, the parts are square, and the proportions are good. If it needs to fit someplace, fine, be as exact as you can. Otherwise, just be consistent. I have story sticks for several items I make repeatedly, and full sized patterns for parts of many more. Both methods, properly used, give consistent results.

Kirk

 

[Paul Chapman]

..... It was a variation on the rod.......l

Not really. The rod is another thing altogether. For your table this is the "rod" way to do it: http://www.owdman.co.uk/howto/howto2.htm

But my way was far simpler (and possibly more accurate because it did away with the paperwork) - no need to make things unnecessarily complicated :wink:

Cheers :wink:

Paul

 

[condeesteso]

My my, what a good read... no-one really falling out, good exchange of views.
Now then, just to stir things up: Is a rod a ruler without marked increments on it? Indeed, isn't a story-stick the same?

 

[Jacob]

.... Is a rod a ruler without marked increments on it?

No it's basically a full sized sectional drawing of an item. Can be done on a narrow board e.g. the front details of a chest of drawers on one edge and the back on the other

etc Indeed, isn't a story-stick the same?

Dunno. "Story stick" is an American term. May refer to something similar to a rod, reduced to a "stick".

 

[Paul Chapman]

Is a rod a ruler without marked increments on it? Indeed, isn't a story-stick the same?

It's really a way of transferring measurements that is accurate and free from errors. A story stick is the same thing. Story stick is the name that they tend to use in the USA.

The example I used above of making and fitting some shelves was a very basic form of rod. By using the measuring sticks I was able to set them so that they fitted the gap (I marked the sticks with a pencil so all I had to do was line up the pencil marks when I got back to my workshop). Provided I transferred the measurement from the sticks to the board I was cutting, I knew it would fit - I didn't need to know the measurements in inches.

You can use rods for both large and small jobs. For example, when measuring a kitchen to make fitted units, you can mark the position of all the appliances and units on the walls of the kitchen and transfer these marks to a rod. You can then go back to the workshop and provided you make the units in accordance with the rod, you know it will fit.

Even a marking gauge is a form of rod. For example, if you need to cut six pieces all the same width and you measure them all individually with a ruler and pencil, there are bound to be differences. But if you use a marking gauge from the face side on each piece they will all be the same because it reduces the error.

Hope this helps.

Cheers :wink:

Paul

 

[AndyT]

This may help, from Ellis's Modern Practical Joinery:

Carefully selected cross-sections show widths and thicknesses; lengths are all shown full size (not truncated as often on drawings).

The book has several pages of text describing these; they were on long thin boards, painted white; plywood would be ideal nowadays. You can do a good job with left-over wallpaper or a roll of lining paper; Ellis was describing a professional shop which would keep a library of rods to make it easy to do repeat orders or repairs.

 

[wyldpuss]

(hammer)

 

[Jacob]

This may help, from Ellis's Modern Practical Joinery:

Carefully selected cross-sections show widths and thicknesses; lengths are all shown full size (not truncated as often on drawings).

The book has several pages of text describing these; they were on long thin boards, painted white; plywood would be ideal nowadays. You can do a good job with left-over wallpaper or a roll of lining paper; Ellis was describing a professional shop which would keep a library of rods to make it easy to do repeat orders or repairs.

That's what I understand as a rod. What Roy and Paul are talking about is a different thing altogether (story stick?).
In practice many details may not be filled in so it wouldn't be quite so recognisable as a full cross section, but all important dimensions would be marked (marks, not numbers), including clearance gaps, position of hardware - everything you need to know during the making process.
All components are then marked up from the rod directly, without any measuring or calculations - it's all been done. This means you can make components in any order and you know they will fit. For a window you could safely order the glass in advance, though for this you'd have to measure (from the rod) and deduct clearance if you hadn't marked it.
Plywood good, MFC 6" shelving even better - nice straight edge and easily erased pencil lines.
Ellis has included the critical dimensions on the sash rod i.e. the inside and outside size of the opening it's going in to. That's where you start a rod (for a door/window etc)

 

[Paul Chapman]

That's what I understand as a rod. What Roy and Paul are talking about is a different thing altogether (story stick?).

I think you'll find we are talking about the same thing. The example AndyT gave is the type of example that most writers will give in text books. The examples I gave were simply variations on it. It's all about being able to transfer measurements in a way that will avoid the sort of mistakes that you will get when you use a ruler - eg you are taking the measurements directly from the space in which the piece will fit (my example of making and fitting a shelf); or taking the measurements directly from a component on the piece you are making (my example of the table legs); or using a measuring and marking device that will not vary (my example of using a marking gauge).

A rod has other advantages, such as being able to draw all the essential components on a piece of wood/paper that is smaller in area than the thing you are making (Andy's example and my example of a fitted kitchen).

So I think we are talking about the same thing. You just adapt the principles to suit the thing you are making, which might be something simple or something complex.

Cheers :wink:

Paul

 

[bugbear]

That's what I understand as a rod. What Roy and Paul are talking about is a different thing altogether (story stick?).

I think you'll find we are talking about the same thing.

Yeah - it's a spectrum.

story stick -> rod -> full size plan.

BugBear

 

[Jacob]

...
I think you'll find we are talking about the same thing. ....l

Could argue this til the cows come home, but what you are doing with your stick is taking measurements. I'd be more inclined to use a tape. I could just as well call my tape a "rod".
The "rod" is the working (production) drawing you make up after having taken measurements (with your stick thing, a tape, dividers, laser device, strides, thumb, whatever).