Any advice on how to cut/file a 45 degree chamfer on a 1mm steel sheet to EXACTLY 45 degrees?

[Ian PParticipant @ianp]

Posted by Jeff Dayman on 24/03/2021 20:18:59:

"PPS Luck your house has all the walls at Exactly 90deg"

As if that has ever happened! (I'd settle for 'somewhat planar' in our house)

In the spirit of the OP's expectations of 'EXACTLY' I would say that most houses are walls at exactly 90 degrees.

In our home I could put a square table in the corner of a room and it might fit perfectly but I dont know for certain that the table is accurately made.

Personally I dont have a high opinion of British housebuilders but I accept fitness for purpose serves here.

Ian P

[HopperParticipant @hopper]

Posted by Neil Wyatt on 24/03/2021 19:29:51:

I've got to cut some dado rail to 'exactly' 45 degrees in the next few days.

Far trickier if you ask me…

Neil

That's what mitre boxes are for. You can buy plastic ones for a few quid these days. Guides the saw at exactly 45 deg and perfecty square. (By woodworkers standards, which if my mate the builder is anything to go by, are not quite up to Michael Gilligan's typical parameters.)

Which maybe could be used for the OP's problem too. Glue some emery paper to the side of the saw blade and hold the job in position on the side of the mitre box while chamfering the edge.

[Ian PParticipant @ianp]

Posted by John Smith 47 on 23/03/2021 13:41:47:

Thanks for all your quick responses
[Note I have now added a PS to my post of 12:36 today]

Regarding accuracy of the 45 chamfer, I need to make a bit load of them at least 32 of them and they ALL need to be able to meet and create a 90° join.

The reason for the accuracy is thatt they are for magnetic guides and even a 0.1mm gap will cause a significant drop in magnetic pull.

I'm not sure what 'magnetic guides' are but if you want the magnetic force to hold these parts together at right angles and you are concerned about a 0.1mm potential gap you might need to use guage plate or have the steel parts hardened.

Since these items have more or less a cutting edge (like a plane blade) they will be very subseptible to damage or burrs so even if it was a perfect 45 degree bevel it might not remain so for very long.

Since you mentioned this was an idea for a 'product' it might be sensible to have a batch made by an engineering company or an individual rather than buying machinery and learning how to use it. As others have said the most appropriate DIY method is that suggested earlier by Andy Stopford .

Are you hoping that the magnetic force will hold two parts together at a right angle just by the contact along the bevelled edge?

Ian P

[Frances IoMParticipant @francesiom58905]

mitre 45deg joins in skirting boards soon separate – the best approach for internal corners is a butt joint but into a shoulder cut in one of the boards.
I suspect the same approach can be used for dado rails

[JasonBModerator @jasonb]

Scribe internal corners on any mouldings and mitre external, As Peak4 said precutting a "mitre" and then using the edge as your scribing line is the way to do it.

Dare not tell Neil that Dado rails is about as popular as the similar named bird these days can't remember that last time I fitted any for a client even in period properties.

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