Cutting stock that is too big for your saw in multiple passes?

[MakeDo]

My Google-fu has not been fruitful in trying to answer this question.

Some background / My situation:
I'm brand spanking new to machining (it evolved out of other maker hobbies). I live in a condo without a garage and have been slowly evolving a guest bedroom into a maker space which now, thanks to the very recent addition of a bench-top milling machine (I'm also planning on adding a lathe sometime next year), is putting on airs of becoming a small machine shop. I envision working with stock that is at least 8"-10" wide / round. I don't think I'm really going to have room for a horizontal band saw (although, if its really the only viable solution, I'll find a way to make it work). I also have access to a local makerspace organization that does have a big bandsaw (but it's an hour drive away). I've read and liked the advice in other threads on this forum about the idea of portaband saws with table adapters for folks with limited space. This looks promising for my situation, except for the limited cutting envelope.

My Question:
Is it viable to cut large metal stock in multiple passes (i.e. starting the cut on one side, then flipping it over and finishing the cut from the other side). As mentioned, I'll have a mill and a lathe to make the final cut look pretty. In my mind, this should be viable (especially if you are using a fence or other such jig), but I wanted to know if there were any gotchas or special safety concerns when cutting metal in this fashion. I'm especially curious if cutting large diameter round tube stock can safely be done by making a cut, rotating the stock, making a second cut, rotating the stock, etc..

Thanks, everyone. Any advice, warnings, alternative approaches will be greatly appreciated.

 

[JimDawson]

Yes, that works. Careful alignment will make a pretty decent cut. I've done this many times. Just think ahead a bit when cutting tubing or angle stock to try to keep the cut against the hard stop.

 

[ch2co]

I do it all the time, just use care and common sense. You don't usually end up with the best looking finish on the parts but there are cures for that.

 

[MakeDo]

Just wanted to add one safety note that I just saw a good demonstration about (in case other noobs, like me, come across this idea).

There is a safety concern when cutting round stock with a vertical band saw (which is how I intend to use the portabandsaw on a regular basis in my make-shift shop). The blade wants to rapidly spin the round bar/tube when it catches it, potentially pulling the operator and their soft mushy parts into the blade. Secure the round stock with some kind of "anti-rotation device" (such as a clamp - see video below) to prevent this. For a great demonstration check out Tom's techniques demonstration on band saw safety (skip to time 3:11).

The other thing with this setup is that there is no moveable blade guard to work with, so that needs to be taken into consideration as you build up your healthy fear and respect for the machine.

 

[brino]

@MakeDo Thanks for posting that.
We should always strive to be sure that people know about the "safety gotchas" with any operation.
If someone is not expecting that they could get a very nasty surprise.

I like to hold round work into a v-block and clamp set, using a spacer between the work and table on the other side of the blade.

Another tip; for thinner sheet or thin walled tubing use a high-tooth count blade. You do NOT want the work jamming in a gullet between teeth and grabbing the blade. I believe the conventional wisdom (rule of thumb) is to always have the work piece thickness spanning at least three blade teeth.

-brino

 

[Surprman]

A safety note: before I had a 4x6 bandsaw I would cut my non-ferrous stock on my 12 inch Dewalt compound miter saw (with a carbide tooth blade - mainly cutting aluminum). It would be loud and the chips coming off the cut would be super hot, but because the movement of the blade was constrained it was pretty safe, until one day I was cutting a 2 inch diameter round price of aluminum. I was only cutting off about a 2.5 inch piece and the blade jammed when the cut was almost finished. Easy-enough I thought, I’ll just flip it over and finish the cut. That worked, but when the cut was finished there was nothing holding the separated 2.5 inch piece down and one of the saw teeth bit into it and spun it like a top. It jumped off the saw with amazing speed, banged into my furnace and spun on the floor for over a minute. (I don’t recommend that)

Feel glad you have a nice slow band-saw.

Rick

 

[gr8legs]

A safety note: before I had a 4x6 bandsaw I would cut my non-ferrous stock on my 12 inch Dewalt compound miter saw (with a carbide tooth blade - mainly cutting aluminum).

A big word of caution on using a chop saw for cutting aluminum:

A couple of weeks ago I did the same thing, cutting some small-ish 6063 aluminum 3/4"x3/4"x1/16 angle for some machine display frames.

The high-speed of the saw put hot aluminum mini-chips everywhere - and even though I was wearing wrap-around safety glasses there was so much back spray (big hint: if you feel chips buffeting your face: STOP!) that a chip bounced behind the safety glasses and embedded itself in my eye. ER visit ensued - nasty business.

Now, when I do the same thing I not only wear wrap-around safety glasses but also a full-face shield. Eyes: only two to a customer; conserve!

Stu

 

[ThinWoodsman]

Couple things to add.

* Check out the SWAG porta-band bandsaw table. Real space-saver, and you get a variable-speed bandsaw with readily-available blades. Table + saw is a bit pricey but still less than those horizontals. Been limping along with one of these for a few years now, and while I don't love it, it certainly is serviceable.

* Before you start your multi-cut, spend a minute or two at the vise. Use a square and a file to score the work on every side, marking where the saw will cut. The deeper you run the corner of the file, the easier it will be to keep the blade tracking, as you can sort of tilt the work up so the blade fits in the scoring, then lower it and the saw will continue on its merry way.

 

[brino]

Now, when I do the same thing I not only wear wrap-around safety glasses but also a full-face shield. Eyes: only two to a customer; conserve!

Great advice Stu, I hope you are fully healed in short order.
-brino

(....and it's certainly no time to be going anywhere near a hospital.)

 

[acruxksa]

1.5" x 10" Hardox. It was a remnant, so I'm not sure if it's 400,450 or 500, guessing 400 or 450 though based on condition of saw blade when I finished (I initially thought it was hardox 500, but don't believe that any longer). 4" X 6" Horizontal Bandsaw. I had to flip the piece. Also let the back blade cover hang for the last 1" or so on either side (not recommended, but it does allow a bit deeper cut). There was still about 1" of material in the middle that flipping didn't reach, so I slide the top blade guide all the way in and tilted the steel to about a 20-30 degree angle. It was a heavy enough piece that it didn't move when tilted.

Just because I do stoopid stuff, doesn't mean others should. Also, yes the camera was close to the back with the blade cover down, but I was holding it at arms length, so I wasn't nearly as close as the video would make it appear.