cutting 1/2" thick aluminum bars on a budget?



Like these? http://agenaastro.com/parts-accessories/mounts-tripods-accessories/dovetail-bars-rails.html
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I just wanted to ask about this possible alternative for cutting the aluminum: a neighbor offered to let me use his Craftsman 10" bandsaw. Would this be able to cut the 1/2" aluminum or not large enough a saw?
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I used a yellow 10" Craftsman to cut aluminum until I found a used 4"x6" metal bandsaw which cuts much straighter and more accurately. The Craftman wouldn't cut straight enough unless the blade guides were in perfect condition and adjusted carefully.
Mine lacked any provision for rip or miter guides until I adapted the table from a small table saw. You can clamp on guide bars but setting them simultaneously parallel to the blade and at the right distance is difficult.
I'd buy the widest blade that will fit, 10 to 14 TPI although 18 will let you cut thinner metal without catching and stripping off the teeth. Sharp-edged, incompressible metal chips don't do the wheels any good.
While the blade speed of a wood-cutting bandsaw is acceptable for aluminum, steel will ruin the blade instantly.
-jsw
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He offered _after_ finding out that you -intentionally- burned out your saw? Are you willing to pay for any damages to the tool you borrow, and will you do so _when_ you break it? Otherwise, do not borrow tools.
Have you taken into consideration that telescope mounts are curved? And do you know how to cut that cove on aluminum bar stock? Just save up the money and buy the proper mount, dude.
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On Sun, 25 Jun 2017 07:02:13 -0700, Larry Jaques

You go easy on your buddy the deadbeat liar, but you're hard on some guy's DIY project. That makes sense to you?
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It will cut it with the right blade if you don't force it. Even a porta-band will do the job.
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On 06/25/2017 01:57 PM, snipped-for-privacy@snyder.on.ca wrote:

Ok, thanks for your response.
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Remember, when you send a boy to do a man's job, it CAN be done, but it will be done more slowly. Make sure the "boy" is properly supervized and not overworked.
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2 words. Band Saw.
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On 06/25/2017 01:45 PM, snipped-for-privacy@snyder.on.ca wrote:

Would you happen to know what size band saw? A neighbor has a 10" saw with 1/8 to 1/4" blades I could borrow.
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How good does the finish need to be? You could use a vertical band saw but the finish won't be very good, not really good enough for a sliding fit if that's what you're looking for. But if you just need the angle for retaining then a bandsaw would be a fast and easy way to cut the aluminum. You will need to make some sort of fixturing to hold the aluminum at the correct angle and width. You could also use a carbide router bit with a rub collar if you have a router. Carbide router bits are great, they last a very long time compared to the HSS ones and are not very expensive. Eric
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On 06/25/2017 03:35 PM, snipped-for-privacy@whidbey.com wrote:

I just recently picked up a Craftsman router table, but no router yet. I've never seen a router in use or used one myself and I have started checking videos on the topic. At some point, I'll pick up a used router.
I suspected the band saw might be a bit problematic for the long angled cuts I needed unless I added a fence maybe... I'm just going to go with the carbide blade the others mentioned, go much more slowly and add small amounts of cutting depth at a time using the table saw. I managed to find a cheap Craig's List replacement over the weekend. I tried to salvage the prior saw, but motor windings tested open for continuity and a replacement motor was far more than I paid for the saw, so just cheaper to get another used one.
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wrote:

If you go asking for a used motor, this is called a Resilient mount. http://www.electricmotorwholesale.com/MARATHON-A279.html -jsw
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On 6/26/2017 8:17 AM, JBL wrote: ...

Good choice.
Here's a tip when you're cutting bevels on a table saw: when you're cutting the second bevel and the 1st one is against the fence, don't have the "point" of the bevel down. It can slip under the fence and even just a little slip can ruin the cut and/or jam the work against the blade.
Having the point up may mean that the fence has to go on the other side of the blade, but that shouldn't be a problem.
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Don't try to route aluminum. At work we do have a Biesse CNC router and a 35' 4 axis router that we do aluminum on every day, but that Craftsman will be too fast for the diameter of cutter you're likely to use, and doesn't support the work firmly enough. You'll probably end up sending the work piece through a wall, and anybody standing between it and the wall. A carbide tipped blade in a table saw will probably be the best tool at your disposal. The cutting force from the saw is mostly in a vector down toward the table and isn't trying as hard to launch the piece as a router would be.
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(snips)

Something that small needs to be clamped down for safety! If they are going to have any holes I would pre-drill them and bolt or screw the parts being cut to a scrap of plywood. Can also attach another scrap as a guide to keep your cut straight.
Agree with all the advice about carbide! Personally prefer a 40 tooth though they are a bit more expensive. Also use stick wax as a lubricant on the blade. Short as your cuts are you can probably get away dry cutting. Even candle wax will work once the blade gets warm enough to melt it. Try some on the second cut and see if it helps.
No current access to a machine shop so I have a bit of experience with improvised metal working. See http://www.mysecondbathouse.com/firstmold.html for what can be done with (mostly) a skill saw.
--
William

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"JBL" wrote in message
I am attempting to make a few "dovetails" which are brackets used to attach a telescope to a telescope mount. If purchased outright, for the kind of dovetails I need, the expense is beyond my budget. I recently acquired some 1/2" aluminum sheet/ bar. The dovetail needs to be 1.75" wide at the base, with the sides cut at a 15 degree angle. Length can vary a bit, but usually about 12-14". My plan was to make at least 3 for the various telescopes I have.
I thought I'd be able to get away with an old circular table saw I had. Last week, I made some 1/4" thick dovetails of a slightly different design using my table saw fitted with a plywood blade. This went well, but when I tried to make these thicker 1/2" dovetails today, I ended up burning out my saw.
Ideas for a cheap way to make these dovetails would be welcome. I've been watching Craigslist for another circular to replace the burned out one, but I don't think it's the best tool for this job without a $30 plus blade made to cut metal and even then I'm not sure it will do it.
Thanks in advance for your help, John
***
While not ideal for it I have severed a lot of 1/2 aluminum flat bar (and thicker) with a 10" table saw. With plenty of lubrication it does ok actually. I wouldn't saw any old carbide blade would do, because I had a couple cheap ones that ripped off all the teeth in one pass, but most name brands do ok for atleast a few cuts. Now I wouldn't put this on an elcheapo table saw, but my Ridgid contractor saw Is only middle of the pack as saws go. I've used it for 13-14 years or so for all kinds of projects. For a couple years it was my dedicated aluminum hacker. Now it only gets used for wood since I bought a horizontal bandsaw for the metal shop.
I don't know if I would venture to cut dovetails with it, but I suppose it might be possible some care and proper feeding. (pun intended) The problem is going to be keeping the blade lubricated Maybe if you could figure out how to make multiple passes you could fill the slot with cutting oil between.
I think a variable speed router and a router table Might be the next totally wrong for it option to consider. I used router as spindles on my early CNC machines. They didn't last long, but one would probably last long enough for the job your describe. Be pretty dangerous too.
The right tool of course is a milling machine and a dovetail cutter. Could probably still use a carbide router bit if you plan lubrication and chip clearance.
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On 06/27/2017 04:53 PM, Bob La Londe wrote:

Thanks. Well, for now, it's all on hold. I've run out of money for this hobby stuff and will have to now wait until the next paycheck to go any further. I actually did manage to properly cut one of the dovetails on the first table saw before it burned out. It wasn't easy and I probably should have tried lub as you and the other suggest, plus it wasn't the right blade. This time, I'll start off with a better blade, more careful and slower cutting, and some lub. That is, when I acquire the spare funds. The idea was to make myself several dovetails first and then use those as templates to make a few more maybe to sell to others. I lack a drill press too, which is a major stumbling block since holes need drilled into the dovetails. I do have one of those small drill holders that accepts a drill and then can drill straight holes. This can actually work before I start cutting any dovetails, but once the much smaller dovetails are cut, there just isn't enough surface area left for the device to line up correctly.
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