How to cut metal frames?

[Justan]

The title says it all. Are there specialized tools for this?

TIA

[Paul2660]

Yup. If you want it to look good it needs to be cut by a special saw with water to help cool the metal. The saw I used to cut on was an Italian brand ( most of the good frame saws are it seems).  These saws will have blades for metal and blades for wood.

You can get away with wood on a miter saw if you have the right set up. But metal is much different. In my city there is one shop that can cut metal correctly. 

Paul

[smjphoto]

Not wanting to contradict Paul , but maybe to add a different perspective...

I've cut nielsen metal frames several times using a  carpenter's standard power miter saw and a miter blade designed for finish miter cuts in wood . I thought the results were fine. I can't tell them from the factory ones. I realize aluminum is "stickier"than wood and will gum up on the teeth eventually. So for high volume use, you might want something better. But for the standard frame chop on powder coated or anodized aluminum frame stock, I'd be very surprised if you weren't successful. (Don't try it with steel.)

I think the water "cooling" for aluminum is really more about being a lubricant to keep the cutting chips from sticking to the cutter's faces.

checking the internet for info about blades produced this quote from Fraud about their non-ferrious miter blade:
This blade produces a smooth, burr-free finish when cutting thin aluminum, brass and other non-ferrous metal extrusions.high tooth count with a 5 degree hook angle allows the teeth to slice efficiently through the material without binding.requirements on the cutting edge greatly differ with non-ferrous metals than with cutting wood.this in mind, Freud formulated a special carbide with high impact strength for this blade.recommends use of a liquid lubricant when cutting non-ferrous metals.can be accomplished with a spray of WD-40 or other similar type of lubricant every 4 or 5 cuts.

hope this helps,
Stuart

[smjphoto]

I should add if you do try cutting aluminum with a power chop box or miter saw, please use safety glasses. Feed slowly to start and make sure the aluminum is well clamped in place. Cutting aluminum is a little different than cutting wood. It can be more "grabby" and can lead to accidents if you treat it like wood. Be careful and proceed slowly till you get a better feel for how it cuts.

Also, some people use wax on the blade to keep the chips from sticking as another option instead of wd 40 or other lubricants.

[Some Guy]

Best thing I've found for framing wood and metal is a table sander with an angle miter on the disk table.  You can fine tune to 1/2 degree if you need to.  I can cut aluminum roughly to about 1/4" and sand it down on the table sander to a perfect fit.

One of these: http://www.sears.com/craftsman-1-3-hp-bench-top-4inch-x-36inch/p-00921514000P

I've had one of these things for decades and it really is indispensable for a lot of stuff.  Had to change the motor's notched V-belt in 20 years.

SG

[Justan]

^I have a slightly bigger version of that platform and would not have thought to use it for this purpose.

Thanks for this and the other feedback offered. A little further searching indicates that there are a variety of saws which do this. CTD is one manufacturer I found they make several kinds of saws for this application. I'm sure there are others.

According to some videos, cutting metal moulding can be done with a cut off disk made for aluminum, a fairly high tooth count metal cutting blade as shown here: https://www.youtube.com/watch?v=1NpccJB7gCI and other saws will also work to varying degrees of precision. Evidently using a torch is a bad idea because it doesn't produce a clean corner.

I may have to give using a saw a try. My goal is to reduce the cost of having wood frames made and to simplify the process. Almost all my works have a unique size and while I can make them the same length, they have varying heights. The thought is to buy aluminum frame moulding in bulk. By not using wood, I won’t need an underpinner to join the pieces so the process is simplified.

I know another artist who uses aluminum frames on his smaller works. He pays about 1/4 of what i do for frames, and customers do not appear to care that the frames aren't wood. The biggest plus is that by carrying his inventory in pieces rather than assembled, he saves an enormous amount of space.

[framah]

Granted, my chop saw is not something you would ever want or need... I have a Pistorious double miter chop saw with 14" carbide blades. I can cut both wood and metal all day with those blades.

I used to use a special lubricant for cutting the metal but don't bother anymore. You seriously don't need "water to cool" the metal while chopping, it is such a tiny amount of metal that you're cutting, heat just isn't a problem.
A wax stick can be touched onto the blade teeth before cutting to act as a lubricant.

Any really good chop saw that will give you true 45º cuts will work using carbide blades or those nonferrous blades. Clamping the frame is a good idea when cutting. Also a good measuring guide will give you repeatable results.

[Paul2660]

The water is not for cooling, (my mistake) intended however to help keep the metal flakes from flying around (mainly into you eyes). 

The saw I was referring to is the double miter, designed for framing, Italian.   

I am sure the other methods will work, however you will find metal is in many cases as much as a good wood frame, if you are off just a tiny amount on one of the cuts, (thus the double miter saw 2 cuts at once), then you frame will not lineup and you will have gaps.  The framing saws will allow you to free up both hands to hold the frame as they are foot operated, unlike other saws which require one hand to pull down the blade. 

In my area, most people don't attempt this without the correct equipment, however I am sure with practice the other methods will work, just watch your eyes, (use protection)

Paul

[Justan]

^Thanks for the tip about the Pistorius brand and related. I agree at this point don’t need a double miter saw but Ebay can be a friend to help find examples…for example.... http://www.ebay.com/itm/Pistorius-Miter-Saw-/281332581025

I figured that for the 5 to 20 seconds it will take to cut aluminum frame molding that liquid cooling probably would not be necessary but possibly needed for bigger frames or longer production runs than I’ll do in the near future.

I'll probably start with a 16" cut off wheel (about $50) and my Ryobi compound miter saw. First i'll have to check the speed of the saw as the cut off disks recommend about 4800 rpm. Don't want it to fly apart!

In a video i posted earlier, the author noted these can deflect if a lot of pressure is applied and produce a curved cut. He recommended cutting slowly enough so that few to no sparks.

[Justan]

The water is not for cooling, (my mistake) intended however to help keep the metal flakes from flying around (mainly into you eyes). 

The saw I was referring to is the double miter, designed for framing, Italian.   

I am sure the other methods will work, however you will find metal is in many cases as much as a good wood frame, if you are off just a tiny amount on one of the cuts, (thus the double miter saw 2 cuts at once), then you frame will not lineup and you will have gaps.  The framing saws will allow you to free up both hands to hold the frame as they are foot operated, unlike other saws which require one hand to pull down the blade. 

In my area, most people don't attempt this without the correct equipment, however I am sure with practice the other methods will work, just watch your eyes, (use protection)

Paul

Good points. Re cost comparison, I pay about $20-25 for smaller wood frames and a friend gets stock + connecting pieces for aluminum for about the same size for $8.

I always use eye, plus ear, plus usually lung protection when using power tools and metal. Metal can produce some pretty damaging fumes.

[smjphoto]

^I'll probably start with a 16" cut off wheel (about $50) and my Ryobi compound miter saw. First i'll have to check the speed of the saw as the cut off disks recommend about 4800 rpm. Don't want it to fly apart!

I would not suggest a 16" cut off wheel if you are referring to an abrasive blade, especially a 16" diameter. Way too much tendency for the blade to deflect.Also, an abrasive blade will produce a lot more heat than a toothed blade and make a mess with the spent abrasive particles. Do you really have a 16" cutoff saw? That is huge and not the best for precision work. Or maybe I'm on the wrong track and don't understand what you are proposing …The video that you linked earlier, the guy was using a large cut off saw (14 or 16") with a cold cut-off blade, but he was cutting steel and cutting it for wielding purposes. A woodworker's miter saw is a much better tool for cutting precision miters for an aluminum frame. A regular miter saw is even better than a compound miter saw, but both will do the job.  I have both cutoff and several miter saws and wouldn't consider using the cutoff for finish miters.
I suggest looking into something like this blade or any of the many like it that fits your compound miter saw:
http://www.amazon.com/D1080N-Diablo-10-Inch-Non-Ferrous-PermaShield/dp/B00008WQ38/ref=sr_1_5?s=hi&ie=UTF8&qid=1399923714&sr=1-5&keywords=non-ferrous+saw+blade
If you have a decent finish blade for your miter saw, I would even try it before buying an expensive blade to find out if it works for you.

The secret to success in chopping miters is in the setup. The cut is only as good as the set up as far as consistency and fit. I saw a u-tube video that breaks it down to a very simple set up and it works very well. (I'm in the construction business and been doing trim work since I was a kid, so I really didn't need to learn how to do this, but I tried his approach and now I use it whenever I'm cutting frames, wood or metal). The video is a bit slow, but really is easy to understand. If you follow his advice and start with a saw that is trued up vertically, you will make virtually  perfect mitered frames without having to adjust the miters with a disc/belt sander.

http://www.youtube.com/watch?v=a5WBUGnRLBE

Stuart

[framah]

Agree.. Forget a cutoff wheel. It's garbage for the precision cutting you need for this work. Cutting steel and welding it together is way different than cutting and aligning the parts with the seam showing.

No one I know in the framing world uses anything like a cut off wheel..not if they want it to look professionally done.

[Justan]

Stuart, thanks for the comments.

> Do you really have a 16" cutoff saw?

Now that you mention it, I’m not sure. I haven’t seen the saw for a while (years). Last time I used it was when I did a hardwood floor. I bought specialized blades for the job for the chop and table saws and both did a splendid job.

Wrt a blade vs. cut off wheel, a blade may produce a more precise cut than a cut off wheel, but I want to try a cut off wheel. Unless there is an inherent wobble for cut off wheels in general, and given the amount of resistance ~ ¾” aluminum piece molding is going to make, I don’t see much chance of the wheel to deflect. I could be wrong but it’s an inexpensive experiment.

OTOH, if my fame maker offers a good value, I may continue to have them do the work. The biggest obstacle for me is the space to do this. Well, that and I’m not a huge fan of using saws.

>The secret to success in chopping miters is in the setup.

True in all things. I liked the digital protractor the video author demonstrated.

[jferrari]

It's not a good idea to use an abrasive cut-off wheel on non-ferrous metals such as aluminum, copper or brass. The reason is that they will "gum up" and prevent exposing the abrasive that is embedded in the wheel to perform the "cut." You want to use a blade designed for non-ferrous metals typically a carbide tipped, triple chip with a negative rake angle.

[Justan]

I remember reading something that hinted at what you wrote, but when it was noted, the authors did not explain the reasoning. Thanks for doing so!

[fdi]

CTD and Pistorius are a couple of the most common double mitre saw's used by framers in the US although there others. Pistourius went out of business but you can find plenty of them used and CTD provides replacement parts for them. My company uses CTD for our metal but those double mitre saws general wood and metal. I have recently purchased a dedicated metal saw that is better and I am eagerly awaiting it's delivery since it will eliminate the need for oil spray and deburing. I prefer the CTD to the Pistourius because it more enclosed to it makes less of mess.

In order for our CTD saw to cut metal well we carbide tipped, high tooth count blades designed for cutting aluminum manufactured by http://ultramitre.com/
Again there are other saw companies that also make some good metal blades but this is who we mostly use.

If we do not use the oil spray the cuts are not as clean (expect for the first few on a new set of blades) and the blades do not last as long. The oil also helps keep the blades for over heating and warping but this is not an issue unless you are doing production.

For deburing the metal we have a piece of 3/4" plywood that is about 1 foot by 2 foot covered with carpet. We just run the cut edge of the metal across the carpet and it is quickly and easily debured.

You can see a picture of our current metal saw here:
https://www.facebook.com/photo.php?fbid=10152068150942410

Before I had a double mitre saw I just bought pre-cut metal in bulk so I could have high quility frames at a reasonable cost and without spending too much time on them.

If you go cheap on the equipment you have to spend more time. That is why I am currently in the process of spending even more money on equipment...to both increase the quality and efficiency. For example, for our wood frames I would not use a cheap mitre saw link those available at Home Depot because they are not stable, sturdy and accurate enough to give a cut that will not have to be sanded and or touched up. Sanding and touching up takes time and time is money. Of course if you are just doing for a hobby then your time is free.

[BradSmith]

Mark,
fyi, the link to the photo doesn't work
Brad

[fdi]

>fyi, the link to the photo doesn't work

Brad, you have to be logged into facebook for that link to work.
Here is another copy of the pic in our newsletter archive:
http://archive.constantcontact.com/fs169/1101763399831/archive/1116022365680.html

[kidgreen]

With 20  years experience I can safely say do not use a cut off wheel. A carbide tipped blade at least 80 teeth will do the job perfectly, repeatedly, minimum burrs (but these are no real problem that a sharp knife can't clean). If a job is worth doing it is worth doing right. My blades for my pistorius double miter saws are $250 each. Do not scrimp and they will last forever and are resharpenable. You do not necessarily need what I use but make sure you get the best you can afford. Ultramitre is a great brand as is Quality Saw.

Good luck