Small table saw

I'm thinking on building a table saw for metals. I would like to be able make precise straight cuts in steel pipes/bars up to 30mm, plates up to 5mm or other small objects. I know I'm going to end up more expensive that buying a new one but I consider that I'm paying for the fun of building it. It would be also a good reason to do something useful with my new lathe.
I considered at the beginning a band saw. But I'm not sure how to make the wheels. Maybe from a large pipe? Or what is the minimum diameter for them. I suppose there is a limit on how much you can bend the saw band.

For the table saw I want to use a carbide disc, maybe something like this. The smallest one from there can make only 1.5mm wide cuts. I don't want to adjust the disc height and angle. Only to have a precise slide and to be able to hold the piece and exact angles. I plan to use a 3-phase motor to have speed control. I already have the inverter of the lathe.

What is the risk for a carbide disc to loose one tooth? For this type of saw you are standing right in the path of a flying piece of metal if this happens. I used a lot carbide discs but only to cut wood with an angle grinder. There was no such danger.

The blade needs to be protected by a guard. I have an Evolution circular saw, primarily designed for cutting wood but will also cut metal. This useage results in lots of hot metal chips flying around the work area. Quite unpleasan and needs careful use. The blades are quite pricey as well. I avoid using it to cut metal. A bandsaw or, for heavy stuff, my old Rapidor are much more civilised.

The feed pressure required is going to be really very substantial, and I would expect it to kick back viciously if you let the pressure up for a second, with a metal workpiece that's likely to be much more dangerous than a woodworking table saw.

If you go this route I would strongly advise you have a chain or hydraulic feed which moves a very rigid work clamp, although I would still consider it a lot riskier than an equivalent bandsaw.

That's the reason why (excepting some truly gargantuan slab-saws in steel mills) every cold-saw with a rotating blade moves the saw head through thecwork in a very rigidly fixed path, and bandsaws are the defacto standard for metal cutting if the workpiece is the moving element.

.

You can buy bandsaw "Bandwheels" as spares for an existing design, or purchase the tyres for a given dimension and fit them to wooden or fabricated wheels.

If I was fabricating one I would get a disk of steel cut (or cut it on the plasma cutter) and use a ring-roller to make the OD out of steel strip (doesn't need to be hugely thick, (1mm would do if it's not too wide) you could probably tack weld and hammer form it round the disk too.

The bigger the wheels the greater the cutting capacity you can have, and the wider the blade you can tension (which improves straight line accuracy), as the minimum wheel size increases proportional to how wide and thick the blade is.

Myford used to make a saw table to mount on the cross slide. The blade was basically a 5” diameter slitting saw mounted between centres. The table could be adjusted for height and the work clamped to it. The metal cutoff saw in our workshop was a very substantial machine with a fine toothed HSS blade. The chop saw type machine by Evolution Rage seem to control the depth of cut with the design of the blade, the control of chips and any broken tips should be contained by the guards but I can imagine the hot chips will scatter widely as the cutting speed is still quite high although slower than the wood only machines. I know a very competent woodworker who lost two fingers to a circular saw, they don’t even blink if you offer your fingers to them.

Mike

Saw table

this thread has some pictures of the Myford saw table.

Mike

A decent band saw is good

The best choppy-uppy system is a grinder with 1mm discs

To achieve a straight cut put the job in a vice and cut along the vice jaw line

You can cut a 300mm x 100mm x 12mm steel plate in half in 2 minutes flat

Have a corner of the workshop set aside for dirty work only

Edited By Ady1 on 20/04/2023 19:52:37

Edited By Frances IoM on 20/04/2023 19:55:54

Jelly, but why would you need to apply a lot o pressure? I searched for some videos with table saws cutting metal and it seems to be no difference from cutting wood. Except it takes much longer. Here somebody is cutting a >20mm plate: **LINK**
It looks like a peaceful event.

I'm starting to consider again also the band saw option. How about using 4 wheels instead of 2? In this case I could have large cutting capacity with smaller diameter wheels. If wheel diameter of 10-13cm is enough I could make them on the lathe. Maybe up to 20cm with some chuck creativity. Somebody seems to have this idea already.

Thank you for all suggestions.

If you make your own bandsaw wheels it may be important to balance them.

I use the Evolution Rage saw blade for thin metals in both my portable circular and radial arm saws; in either case, the saw is mechanically guided but advanced, with great care, by hand; this is made possible by the chip-limiting form of the teeth.

A bandsaw is a very handy tool in the workshop but an option is to use a sliding angle grinder guide. Lots of DIY builds on the Internet, Youtube, etc.

Video of a DIY bandsaw on Youttube using wooden wheels and a simple sliding angle grinder guide. . **LINK**

After seeing some Youtube videos I changed my mind, no more table saw. It is too dangerous comparing with the band saw. Some of the causes of accidents are not even that obvious.

I did some research and I found that for a 1mm thick blade you need a wheel at least 18" in diameter. That might be difficult to turn in my lathe. And I don't know from where to buy a bar with that diameter. I'm looking for some thick delrin plate, or another strong plastic.

The only progress so far is that I found a local company that sells carbide band saw blades at any length you want. So I'm not constraint to some predetermined diameter.

That sounds a bit of a thick blade, the ones I use on my Femi bandsaw are 0.65mm and the wheelsabout 200-225mm. Do you really need carbide, M42 last well.

I find that a saw like THIS does the jobs I need to cut and on the odd occasion when I need to cut something bigger a mini grinder or larger depending on what it is

I'm wasn't sure about blade thickness. Now I saw that 0.65mm is the most common value. The same for carbide blade. I measured precisely the space between the center and the tip of the cutting tool and it seems that I can turn something up to 210mm in diameter. So for a 0.65mm blade maybe I'm close.

I want to build a vertical bandsaw to be able to cut also metal plates. It will have 3 or 4 wheels.

Edited By Sonic Escape on 25/04/2023 21:36:39

If you put a holder with a L/H tool onto the position nearest the operator you will easily gain another ?50mm+ on radius..

Edited By DiogenesII on 26/04/2023 06:35:24

Yes, I didn't think of that! It is a very good idea

The thing to watch with 3 and even more so with 4 wheel saws is that you don't get as much wrap around of the belt on the driven wheel and will end up with it slipping unless the wheels are excessively large

Most of the small bandsaws that have a single pivot can also be set vertically for cutting sheet metal, though the throat depth is generally a bit less than a true vertical,  The down side of only a vertical is you cant cut say a 4fy length of bar in half as the left hand end will hit the frame. How wide/long a piece of metal do you expect to be cutting?

Edited By JasonB on 26/04/2023 07:10:40

Hmm ... that could be an issue. Today I read more about 3 or 4 wheels bandsaws and there are a number of reasons why almost no manufacturer builds them.

I was rethinking what requirements I want. What I fell is missing is the ability to precisely cut small parts. Plates up to 250mm, tubes up to the same length or any other things more or less in the same dimension interval.

If I want to cut long pieces I'll just use the angle grinder like I do now. I just finished a large metal workbench and there was no problem in cutting everything with abrasive tools. And to cut a larger plate will be quite a rare event. I can order it to a laser cutting shop.