Wooden Straightedge ?!?

[graduate_owner]

Coming back to the making of try squares, could perspex or similar plastic material be used instead of wood? I would expect the stability problem to be solved, but what about durability?
I have some 1/4 inch thick pieces of transparent material, about 2ft x 1ft - it's fairly rigid as a sheet, not sure about hat a strip would be like though. I was thinking to cut some strips off these to make straight edges and squares, but I don't think planing them straight is likely to work (!!), just a table saw cut edge.
Does anyone have any experience of plastics used in this way, and what would be the best plastic to use?


BTW, as a not-very-competent DIY woodworker, I find myself somewhat in awe of a forum member who has spent nearly 50 years as a professional cabinet maker. That sort of experience is certainly something to be proud of.

K

 

[GazPal]

Totally confused now.
Plus, it just occurred to me that no-one has ever explained to me what the advantage a flat plane sole is. :?

Having a flat plane sole makes it easier to plane surfaces to a consistentfinish on the same plain. A convex sole will tend to cause a plane to hollow timber, whilst a concave sole will tend to crown timber. Viewing Record #020 circular plane helps illustrate the usefulness of such sole shapes.

http://www.record-planes.com/39/record- ... lar-plane/

 

[Paul Chapman]

but I don't think planing them straight is likely to work (!!)

Most plastics (perspex, Formica, etc., etc) can be planed OK. Best to make sure your plane is very sharp, finely set and probably best to hone the blade at a steeper angle than normal.

Cheers :wink:

Paul

 

[Corneel]

With a concave sole it is very difficult if not impossible to take fine shavings. So it's not very important for a jackplane, but a smoother and a jointer you probably want flat. At least not concave.

 

[GazPal]

A much steeper angle if possible. One of the original purpose for the #060.1/2 low angle block plane related to planing perspex, but with a honing angle set between 80 - 90 degrees. This produces more of a scraping action, but leaves behind a chatter free, clear and polished surface.

 

[graduate_owner]

Thanks for that info Paul, I had no idea you could use a plane on plastics.

K

 

[Paul Chapman]

Thanks for that info Paul, I had no idea you could use a plane on plastics.

When I made this dovetail marker in perspex, I planed the edges and used a router to cut out the shaped pieces

Cheers :wink:

Paul

 

[Cheshirechappie]

Coming back to the making of try squares, could perspex or similar plastic material be used instead of wood? I would expect the stability problem to be solved, but what about durability?
I have some 1/4 inch thick pieces of transparent material, about 2ft x 1ft - it's fairly rigid as a sheet, not sure about hat a strip would be like though. I was thinking to cut some strips off these to make straight edges and squares, but I don't think planing them straight is likely to work (!!), just a table saw cut edge.
Does anyone have any experience of plastics used in this way, and what would be the best plastic to use?


BTW, as a not-very-competent DIY woodworker, I find myself somewhat in awe of a forum member who has spent nearly 50 years as a professional cabinet maker. That sort of experience is certainly something to be proud of.

K

Hunting about the secondhand market (or the dreaded 'bay) may turn up some draughtsman's T-squares and set-squares. The larger set-squares were often made in translucent perspex or similar, and sometimes in very large sizes. No good for use with a marking knife, but fine with a pencil.

 

[Trafalgar]

Perfectly serviceable metal ones are relatively cheap so I've never been tempted. But according to Chris Schwarz, the reason wooden ones are shaped the way they are on the upper edge is to regularise the amount of moisture entering and leaving the wood (the majority coming in through end grain) and so in that way help maintain their uniformity. After all, they've been used for many a year to make excellent and exceptional furniture.

They're shaped that way so one wouldn't accidentally use the wrong edge.

 

[graduate_owner]

The wrong edge - you mean use the 30 or 60 degree instead of the 90 degree? That's the sort of thing I do, (well, almost) then wonder why things don't fit.

K