aluminium bar to dovetail: doable?

[alacant]

Hi everyone. I've some 80mm x 15mm aluminium off-cuts. What sort of tools would I need to make it into a wide dovetail? TIA.

[REMSTAR]

Hi,

    To make a dovetail you would need a milling machine, a dovetail cutter with the angle you wish to produce and preferably something to measure with. That's about it. Or if you're handy with a file you could do it that way, but you'd really have to want to if you were to try that. Very difficult.

 

[Cornelius Varley]

And a drill.

[Peter Drew]

I've made them using both methods and believe  me the milling machine option is the easiest!, doing it by hand is doable if you haven't got access to a machine, cut the angles roughly with a hacksaw first, it wil save your elbows.   l

[Davey-T]

Here's one I made a while ago with adjustable front bolt, about 300mm long, cut the slope with a battery circular saw and finished with a file.

Dave

[alacant]

Thanks for the hints.

JTOL: What sort of (milling? drilling?) machine would I need? The dovetails are gonna cost me over €200 if I buy them. Don't know where to start looking at machines.... If I stick around in this hobby, I'm sure such a machine would be useful for other stuff too...

[Davey-T]

Something like this, be cheaper to buy dovetails, LOL

Dave

 

[jambouk]

What length and width dovetails do you need? And how many?

 

 

[alacant]

1x52cm 1x43cm. Yeah, I can see it's not doable:(

[Flyingfuzz]

Find a local engineering workshop they will often do this for a few pounds.

[Zakalwe]

A woodworking table saw will easily cut that thickness of ally, especially if it has a carbide blade. Set the blade at an angle to form the dovetail sides and use plenty of tallow as lubricant.

The bolting holes will be easy wiith handheld tools.

No milling machine needed at all.

[Zakalwe]

 

[alacant]

Hi. Thanks. Comparing with an existing wide dovetail plate I have along with the aluminium bar I need to shape... It doesn't seem to be a case of a simple angled cut...

[Davey-T]

That's why it's in two pieces.

Dave

[Zakalwe]

With a bit on ingenuity to make some clamps you could probably do that on a table saw with two cuts. There'd be a bit of undercut, but it'd work.

I wonder how a dovetail router bit and a router table would manage......I'd be willing to wager that it'd be doable as long as you can find a bit with the right angle.

[Davey-T]

I've routerd aluminium using TC bits, bit hairy if it jams up but doable, wouldn't recommend it if you're not used to routering 

Dave

[Zakalwe]

On 11/03/2017 at 23:59, Davey-T said:

I've routerd aluminium using TC bits, bit hairy if it jams up but doable, wouldn't recommend it if you're not used to routering 

Dave

Is it the bit that jams? If so, that's usually caused by not using enough lubricant. Ally tends to bind to the cutting surface- the cure is to used sharp bits and lots of cutting soap.

[Davey-T]

1 hour ago, Zakalwe said:

Is it the bit that jams? If so, that's usually caused by not using enough lubricant. Ally tends to bind to the cutting surface- the cure is to used sharp bits and lots of cutting soap.

Usually use PTFE spray, works ok on MDF not so well on ally'

Dave

[Zakalwe]

2 hours ago, Davey-T said:

Usually use PTFE spray, works ok on MDF not so well on ally'

Dave

A bar of cutting soap is what you need...it makes blades go through ally like a knife through butter. Tallow or even some soft candle wax works well too. Keep checking for adherence tot he cutting edge nothing kills the cutting tool as quickly and it wrecks the cut surface.

[Davey-T]

53 minutes ago, Zakalwe said:

A bar of cutting soap is what you need...it makes blades go through ally like a knife through butter. Tallow or even some soft candle wax works well too. Keep checking for adherence tot he cutting edge nothing kills the cutting tool as quickly and it wrecks the cut surface.

Got some Rocol but tends to fire it off the tool so end up with more on me than the job 

Dve

[Zakalwe]

4 hours ago, Davey-T said:

Got some Rocol but tends to fire it off the tool so end up with more on me than the job 

Dve

Sounds messy!?

Many years ago when I used to stick bit of metal together we had long bars of cutting soap. A rub of that stuff on cutting edges was superb...no fling and it really stopped the chips from adhering to the cutting edge. Strangely I can't seem to find it anywhere online. Great stuff though.

[1parsec]

Job for a milling machine.  Much safer, less messy and quieter !
Best to use the right tool for the job. 

[Davey-T]

1 hour ago, 1parsec said:

Job for a milling machine.  Much safer, less messy and quieter !
Best to use the right tool for the job. 

Have you seen the price of them 

My son in law has one but it's an 8 hour round trip so just have to carry on bodging 

Dave

[Bizibilder]

There is no real reason for a dovetail to have sloping sides.  If the bar is rectangular in section and thinner than the depth of the dovetail holder the holder will grip it when tightened.  It will "nip" the top corners of the rectangle but a bit of judicious filing should make an acceptable job if felt necessary.  If the dovetail is too thick then just filing the part held by the dovetail should be sufficient. If it is Ali then a new coarse file will shift it quickly enough.  The angle can be found using a simple angle gauge or protractor.  A smooth file to finish should make a presentable job.

[Davey-T]

I always fit a safety bolt at the front in case of slipping.

Dave