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Equipment Discussions >> ATM, Optics and DIY Forum

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Chuck Hards
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Reged: 05/03/10

Loc: The Great Basin
Re: Makin' long dovetail saddles the quick & dirty way new [Re: careysub]
      #6231119 - 12/03/13 10:43 AM

I've been cutting and routing aluminum & plastics with woodworking tools for 30 years without a mishap. This specifically was the gist of my S&T article in March of 99. The tube rings, bridge plates, and other detail parts of those scopes were done like this.
I hesitated to post those methods here because I had years of woodworking experience on shop tools before I ever cut a piece of aluminum on the table saw or took a router to it. I wouldn't advise someone to try it as their first experience with non-ferrous metal fabrication. Much good advice has been posted in this thread already, just be careful and if you are timid about using these tools at all, DON'T DO IT alone. Work with someone with experience until you get the processes down.

Always wear eye protection. With aluminum, I typically wear both safety glasses AND a full face shield.


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lukasik
Carpal Tunnel
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Reged: 10/11/05

Loc: Lawrenceville, Georgia
Re: Makin' long dovetail saddles the quick & dirty way new [Re: Chuck Hards]
      #6231136 - 12/03/13 10:52 AM

Ditto on the safety glasses and face-shield Chuck. I cut a lot of aluminum on my table saw. Make sure there is nothing whatsoever to distract you from the task such as hot chips down your shirt! Button up your collar. WD40 as a lubricant works OK but can smoke a bit. The waxy band saw lubricant can mitigate chip buildup on carbide tips.

Above all be safe. If you're really intimidated by the task, think again before proceeding. I also wouldn't tackle thick stuff before gaining experience on thinner material.


Best Regards,

Bob


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Geo31
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Reged: 01/28/13

Loc: Kingwood, TX
Re: Makin' long dovetail saddles the quick & dirty way new [Re: lukasik]
      #6231244 - 12/03/13 11:46 AM

And once again (CANNOT be stated enough), use guards as much as possible. They are there to save your fingers and maybe even your life.

Don't ever work distracted or tired. Easiest way to remove fingers or worse.

I was on a speaker building mailing list some years ago and chatted with a fellow about his Delta Unisaw (I still really want one of those). He had wanted one for a long time as well. He got it all set up, sans guards, and just HAD to try it out, despite being tired. He described for me how he actually watched himself run 3 fingers through the blade of the saw.

Think twice. Think three times. Don't work distracted. Don't work tired. And DON'T take anything for granted when using power tools - especially when running aluminum.


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woodscavenger
sage


Reged: 08/20/13

Loc: Boise, ID
Re: Makin' long dovetail saddles the quick & dirty way new [Re: careysub]
      #6231254 - 12/03/13 11:53 AM

I like the aluminum channel/wood combo. Nice and clean

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Old Dinosaur
Carpal Tunnel
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Reged: 05/08/07

Loc: Down there on the river
Re: Makin' long dovetail saddles the quick & dirty way new [Re: woodscavenger]
      #6231261 - 12/03/13 11:57 AM

I've cut a lot of aluminum plate on a table saw, including many dovetails. I use a fine carbide tipped blade.
Go slow, use care like you would with any power tool.


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mark cowan
Vendor (Veritas Optics)
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Reged: 06/03/05

Loc: salem, OR
Re: Makin' long dovetail saddles the quick & dirty way new [Re: John Jarosz]
      #6231281 - 12/03/13 12:04 PM

Quote:

I've never seen anyone use a router on aluminum and I can't imagine it working well but others apparently do it successfully.




Hard to cut circles or rings with a regular saw...

Best,
Mark


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Gordon Rayner
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Reged: 03/24/07

Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231431 - 12/03/13 01:19 PM

A 12 inch disc stationary table sander has been used to make bevels, using the tilting table and/or the miter slider and/or a hardwood support-holder with the correct angle sanded on one of its faces.

The length is limited to less than the example shown by the OP, unless one has a very large ( 20"- 30" ?) industrial disc sander. I wear gloves, and keep a water container nearby to occasionally immerse the workpiece.

One-sided or two-sided female dovetails can be made by screwing one or two beveled pieces to a plate. There are several ways to secure the unbeveled mating surfaces of a one-sided arrangement.

One-sided tapered dovetails (ff. WW II Zeiss 10 x 80 x 20 deg. inclined binoc for Kriegsmarine) both male and female, are easier to make than tapered 2- siders . But none of the tapered types allow fore-aft positioning.


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StarStuff1
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Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231529 - 12/03/13 02:04 PM

Quote:

Quote:

I've never seen anyone use a router on aluminum and I can't imagine it working well but others apparently do it successfully.




Hard to cut circles or rings with a regular saw...

Best,
Mark




I cut circles 6-in or larger in hardwood very frequently with my 10-in Craftsman table saw.


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mark cowan
Vendor (Veritas Optics)
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Reged: 06/03/05

Loc: salem, OR
Re: Makin' long dovetail saddles the quick & dirty way new [Re: StarStuff1]
      #6231570 - 12/03/13 02:25 PM Attachment (18 downloads)

But can you cut a perfectly smooth 20" ring 3/4" wide from 1/2" aluminum sheet??

FWIW, I use a 1/8" straight solid carbide bit to make the initial cuts (in the waste area), then a 1/4" spiral carbide bit to do to the final shaping. Don't forget the oil!

Best,
Mark

Edited by mark cowan (12/03/13 02:34 PM)


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careysub
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Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231669 - 12/03/13 03:23 PM

Quote:

But can you cut a perfectly smooth 20" ring 3/4" wide from 1/2" aluminum sheet??

FWIW, I use a 1/8" straight solid carbide bit to make the initial cuts (in the waste area), then a 1/4" spiral carbide bit to do to the final shaping. Don't forget the oil!




When doing the initial grooving, how deep a cut do you make?


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mark cowan
Vendor (Veritas Optics)
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Reged: 06/03/05

Loc: salem, OR
Re: Makin' long dovetail saddles the quick & dirty way new [Re: careysub]
      #6231722 - 12/03/13 04:05 PM

Probably a little less than 1/4". The way it cuts will let you know.

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Chuck Hards
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Reged: 05/03/10

Loc: The Great Basin
Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231737 - 12/03/13 04:15 PM

You have to remember that milling machines use essentially the same cutting materials as router bits. With a router, you lack the mechanical stage control so make do with jigs and fixtures. But the physical cut into the material is very similar.

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StarStuff1
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Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Makin' long dovetail saddles the quick & dirty way new [Re: Chuck Hards]
      #6231833 - 12/03/13 05:18 PM Attachment (26 downloads)

Mark, I don't cut aluminum on my tablesaw...well only a couple of times in the past and it was thin stuff and not rings.

Here is an example of UTA rings I made a couple of years ago. The outside cut with the table saw and the inside with a Roto-Zip (or router, I don't remember).


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Geo31
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Reged: 01/28/13

Loc: Kingwood, TX
Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231853 - 12/03/13 05:31 PM

Quote:

Don't forget the oil!




How do you feed the oil? Or do you just apply it before starting the cut and keep going?

So far I've only routed thin (0.040") material.


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roscoe
curmudgeon
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Reged: 02/04/09

Loc: NW Mass, inches from VT
Re: Makin' long dovetail saddles the quick & dirty way new [Re: Geo31]
      #6231933 - 12/03/13 06:33 PM

I was surprised to discover that thicker aluminium cuts better than thin - if you want to cut sheet-metal, best to clamp it between a couple of pieces of plywood or something, and cut the whole sandwich.

I was also surprised that Aluminium is really no harder to cut than really hard maple or hornbeam..... sure is noisier, though!

R


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John Jarosz
Astro Gearhead
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Reged: 04/25/04

Loc: Fairfax, Iowa
Re: Makin' long dovetail saddles the quick & dirty way new [Re: mark cowan]
      #6231982 - 12/03/13 07:04 PM

Quote:

But can you cut a perfectly smooth 20" ring 3/4" wide from 1/2" aluminum sheet??

FWIW, I use a 1/8" straight solid carbide bit to make the initial cuts (in the waste area), then a 1/4" spiral carbide bit to do to the final shaping. Don't forget the oil!

Best,
Mark




Mark:
What RPM on the router?

Thanks


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mark cowan
Vendor (Veritas Optics)
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Reged: 06/03/05

Loc: salem, OR
Re: Makin' long dovetail saddles the quick & dirty way new [Re: John Jarosz]
      #6232113 - 12/03/13 08:19 PM

Whatever it came with... That's probably 25K or so. Variable speed would be helpful, but I haven't got that yet.

As to oil, I just apply it on the top over the direction of the cut and reapply when it runs out.

Best,
Mark


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Geo31
Carpal Tunnel
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Reged: 01/28/13

Loc: Kingwood, TX
Re: Makin' long dovetail saddles the quick & dirty way new [Re: roscoe]
      #6232318 - 12/03/13 10:09 PM

Quote:

I was surprised to discover that thicker aluminium cuts better than thin - if you want to cut sheet-metal, best to clamp it between a couple of pieces of plywood or something, and cut the whole sandwich.

I was also surprised that Aluminium is really no harder to cut than really hard maple or hornbeam..... sure is noisier, though!

R




In my case, I rough cut with a jigsaw and finished on the router table with a pattern bit and the pattern double-sided taped to the pattern.


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don clement
Vendor (Clement Focuser)


Reged: 02/02/11

Loc: Running Springs, California
Re: Makin' long dovetail saddles the quick & dirty way new [Re: Geo31]
      #6232452 - 12/03/13 11:20 PM

Taking too small a cut can actually dull your tool. http://www.cnccookbook.com/CCChipThinning.htm

Don


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careysub
Carpal Tunnel
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Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: Makin' long dovetail saddles the quick & dirty way new [Re: tim53]
      #6232798 - 12/04/13 07:09 AM

This is a good reminder to "think outside the box" a bit.

Instead of copying the profiles of commercial dovetails (a box encouraged by the very term "dovetail"), look at the shoe you are making it for and consider how the clamp/screw engages and make a simple/convenient profile, like a simple step, that works with the target shoe. Stacking two flat bars might work, as well as any number of wood/light aluminum shape combo arrangements.


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