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I'm following the book Tools - by Charles Platt where he suggests that it is really important to use a cork-backed steel ruler.

I want to make a cork backed steel ruler as I'm not getting one on any online store where I'm living in India. I have a steel ruler - and I can perhaps get a cork sheet online.

What is the thickness of the cork sheet I should buy? What kind of glue should I use to stick the cork sheet to the steel ruler?

Are there any other things that I should keep in mind while making this?

Caleb
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saraf
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    TBH I think this barely qualifies as being within the remit of Woodworking. But apart from that, consider Chris Platt's judgement of it being "really important" just one guy's opinion! I don't know of anyone else who insists they're even particularly useful, much less vital. Aaand, not a few woodworking books suggest strongly that the marking on a rule should be as close to the surface as possible while any backing material obviously increases this distance — increasing the chance of parallax errors as you view from different angles. And it also makes any rule modified this way single-sided. – Graphus Nov 26 '20 at 15:39
  • BTW what is the supposed advantage of the cork backing? – Graphus Nov 26 '20 at 15:39
  • Agree that holding the ruler above the work by any thickness is not helpful. – Aloysius Defenestrate Nov 26 '20 at 23:09
  • The book says - "Your ruler must be 18" long and should have a cork back to stop it from sliding around. This is more important than it sounds." – saraf Nov 27 '20 at 10:04
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    "Must" is an awfully strong word. I guess I'd better head to the shop and chuck the 6" & 12" rules from my combination squares. And all my longer ones had better have some cork applied ASAP, else the woodworking police are going to come take my tools! If I have issues with a rule sliding, it's because I'm measuring on a vertical surface and I'll lay the piece down, get a clamp or find a helper. – FreeMan Nov 27 '20 at 13:50
  • :-D hahaha ... I guess that he meant - that if you are a beginner and are just buying tools - it would be better for it to be an 18" one. The book is oriented towards beginning woodworkers and DIY. – saraf Nov 27 '20 at 14:49
  • In any - case, if I had to make one - then I gather that I will need to buy the thinnest cork possible - thanks @Graphus – saraf Nov 27 '20 at 14:53
  • That... that quote is just plain ridiculous. Backing a steel rule with cork (for one or both of two reasons) is a draughting tip :-| As far as its applicability to woodworking in general, I can't think of one situation where my rules not being backed with cork has been an issue. As far as 18"/460mm being a must, what about 12"/300mm and 6"/150mm?? Those are far more practical sizes in day-to-day woodworking for the majority of users! – Graphus Nov 27 '20 at 15:54
  • hmmmm .... I thought as much ... as there are NO cork backed steel rules available here. This is a separate question - but - there is a recommendation that says "The countersink must have only one flute and must be ½" diameter." ... what's up with that - the most commonly available ones on amazon are 5 flute ones ... I will post this as another question later. (note: I am a newbie.) – saraf Nov 27 '20 at 16:13
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    If you did still want to back a rule with cork it's possibly worth noting that it may be as difficult to find that as the rules themselves! The cork-backed rules I've seen and handled myself (all made for draughtsmen/architects BTW) the backing has been extremely thin, certainly less than 2mm and possibly under 1mm in some cases. I've never seen cork that thin for sale that I can recall (not that I have looked I must admit). Now, re. the countersink thing, yet again that's an opinion being stated as a fact! Yes, such countersinks are great on wood but they are by no means essential [contd] – Graphus Nov 28 '20 at 18:30
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    ...and there are many current-day situations where you want a countersink of a specific diameter (e.g. for doing recessed screwheads, where the countersink in the wood isn't grossly oversized for the size of the screw used) so to specify a single diameter is again very short-sighted. – Graphus Nov 28 '20 at 18:31
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    In general, be wary of "recommendations" stating "must". In general, one "must" use common sense and care when using power tools to avoid injury or damaging your work, however, that's about as "must" as it comes to wood working. If you're building, you "must" follow codes or your building won't be approved for occupancy, but, frankly, even that is an option (an expensive one, but an option). I wouldn't even say your tool kit "must" contain a saw for wood working - there are other ways of shortening wood. It may not be pretty, but call it a style & sell it for $$$$$! – FreeMan Nov 29 '20 at 16:45

2 Answers2

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I'm following the book Tools - by Chris Platt where he suggests that it is really important to use a cork-backed steel ruler.

I have an 18" cork-backed steel ruler, and also a 6" one. The cork is maybe 1/16" thick, and it does help prevent the ruler from sliding around on slippery surfaces. Wood, however, is not a particularly slippery surface, and steel rulers don't tend to slide around on it. In fact, if I'm using one of those cork-backed rulers as a straight edge, I tend to turn it over so that the steel face is against the wood, and slipping is never a problem.

The book you're looking at isn't a woodworking book -- it's broader than that. Charles Platt is a pretty reliable source, but I think you have to take his suggestion that a cork backed ruler is "more important than it sounds" in the context of someone who works with a wider variety of materials, not just wood.

If you're mainly doing woodworking, I wouldn't worry for a millisecond about the lack of cork backing on your ruler. And no matter what materials you're using, don't get too caught up in having exactly what someone else says is the right collection of tools. If you don't have a cork-backed ruler and your ruler keeps slipping on a surface like sheet metal, just stick a piece of duct tape, gaffer's tape, friction tape, etc. on the back. Call it a "life hack" if you like. ;-)

Being a "maker" is all about finding ways to create what you want using what you have. Consider Platt's advice and the reasons behind it, but don't get caught up in assembling his perfect list of tools, because you are not him.

All that said, you asked about how to make a cork-backed ruler. If you have some very thin cork sheet and a steel ruler, then all you need to do is to cut a piece that's about 1/4" shorter and 1/4" narrower than the ruler you're using, and stick the cork to the ruler. You can use a spray adhesive like 3M 77 or 3M 90, contact cement, or even thin carpet tape or other double-sided tape. I'd stay away from PVA (wood) glue or epoxy, as those are both likely to soak into the cork and harden it, which would defeat the purpose of using cork in the first place. Try to make sure that the whole surface of the cork adheres to the ruler (so that particles don't later get between the cork and ruler).

Following up:

In the US, you can find thin cork sold as non-adhesive and self-adhesive contact paper, shelf liner, and tape. Check craft stores and home improvement stores. Also, you might want to look more carefully for cork-backed rulers; I think you said that you're in India, and a search for "cork ruler" on amazon.in turns up a number of options.

This is a separate question - but - there is a recommendation that says "The countersink must have only one flute and must be ½" diameter." ... what's up with that - the most commonly available ones on amazon are 5 flute ones

We had a recent question (Why is my countersink bit making hexagonal holes?) about countersinks; the reason Platt wants you to get one with a single flute is to help a beginner avoid problems like the hexagonal holes that result from chatter when used with a handheld drill. He's similarly prescriptive in Make: Electronics where he tells you that your multimeter "must" be digital. He's not expressing a strong opinion; it's just that the book is written with the expectation of a digital meter, and analog meters don't afford the needed resolution. Platt's books are easy to follow, and part of the reason for that is that he sets you up to avoid some of the problems that beginners often run into.

Caleb
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  • +2 if I could, excellent Answer. – Graphus Nov 28 '20 at 18:21
  • Thanks for the wonderful answer - 'the reason why Platt wants me to get one with a single flute' addresses my question about the countersink bit quite well! Re: the cork backed ruler - the options that turn up on amazon.in are imported options that cost about 10 times that of a non-cork backed steel ruler, and come here all the way from the USA. (Makers: Westcott, Armada ...) – saraf Dec 01 '20 at 17:35
  • (Cannot visit an atom-space craft store at the moment due to Covid-19 restrictions.) – saraf Dec 01 '20 at 17:43
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If you want to make a steel rule non-slip, how about self-adhesive baize instead?

Some of this can be very thin indeed. The thinner stuff will pick up less sawdust and be easier to brush clean, as well as putting the markings closer to the surface.

Like cork this will also make it non-marring, though your rule shouldn't damage the surface anyway

Chris H
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