Cutting O1

[Steve355Participant @steve355]

I wonder if I’m barking up totally the wrong tree.

I have been making wood plane blades for a while now. The process requires a piece of 3mm O1 tool steel to be cut into a particular shape, then tapered with a surface grinder before being profiled, hardened and sharpened. See a pic below of one of these blades being ground on the surface grinder.

It’s the cutting part I have trouble with. Basically these blades are 8” long, and require 2 lengthways cuts plus a cross cut. The cross cut is easily done with a hacksaw but the lengthways cuts are not – too long for the hacksaw and they need to be dead straight.

I have been using my little Burke horizontal mill to do this, but it’s an absolute pain to set up for such a simple cut. I can’t believe anyone who knows what they are doing, uses a horizontal mill for cutting 3mm plate tool steel, which is very soft in its annealed state.

I came across the Vevor 8” bench shear which looked hopeful. Clearly it would introduce some bending/twisting action but this may be recoverable from.

If anybody has any great ideas, I’d be very pleased! I’m spending far too long messing around, making these simple cuts.

 

[noel shelleyParticipant @noelshelley55608]

1 or 1.5 cutting discs in a 4.5 angle grinder. used carefully you will get good results BUT let the disc cut at it’s own speed DO NOT force it ! use 2 hands to hold the grinder and clamp the work so it does not vibrate. Noel.

[bernard towersParticipant @bernardtowers37738]

Any reason why you can’t just hacksaw it with guide plates clamped to it and then finish with your surface grinder after all it sits there begging to be used.

[Dave HalfordParticipant @davehalford22513]

Plasma cutter against a wooden guide the cheapy Parkside Lidl one would do that easily in a minute

[Steve355Participant @steve355]

Yes, an 8 inch cut with a hacksaw is well beyond the throat of the saw (and takes ages). I have quite a few to make. Also, the surface grinder will do one edge of the work, but not the other.

on Noel’s point, I’d discounted the angle grinder due to heat and inaccuracy. Not saying it can’t work. They always feel like a bit of a blunt instrument to me, not very controllable. I was thinking it needed to be something slow. In fact, the horizontal mill is good in that, it provides a very accurate cut and no significant residual heat. It just takes ages to set up, despite jigs and things, I still get sticking problems with the blade. The whole thing is a pain.

Which is why the shear looked good. However, one side of the cut does get curled up. And it may not be able to handle 3 mm plate.

https://uk.vevor.com/plate-shear-c_10810/8-203-2mm-manual-hand-shear-steel-metal-plate-shear-cutting-solid-long-handle-p_010589800419

 

[KenLParticipant @kenl]

A vertical bandsaw running at less than 100m/min using a wide M42 blade will fly through it and with a bit of practice will cut straight. Use the finest tooth blade you can find and apply cutting oil sparingly to the blade with a brush.

[Steve355Participant @steve355]

I have a plasma cutter, but it always seemed to me like something the Brinks mat robbers would use to break into a bank vault. I used to cut 6 mm mild steel, and it left a ragged edge and dripped molten metal on my lawn.

I do have a horizontal bandsaw, for which I made a vertical table sometime ago. But I couldn’t get it to cut O1 with the blade that I had. I ended up giving up on it at the time. But that may be worth another try with a more suitable blade.

[Steve355Participant @steve355]

here’s the bandsaw table. Could easily have a fence on it that would allow a straightish cut. Might work.

[Steve355]

On Steve355 Said:

I do have a horizontal bandsaw, for which I made a vertical table sometime ago. But I couldn’t get it to cut O1 with the blade that I had. I ended up giving up on it at the time. But that may be worth another try with a more suitable blade.

That bandsaw should cope easily.

Use an M42 (Bi-Metal) blade and run at a slow speed with a bit of lubrication. If you use a wide blade (13mm+) and don’t “force” the cut you probably won’t even need a fence.

The most important part is to set the blade up very carefully every time you fit a new blade, look at the various You Tube videos for detail on adjusting guides, drive wheels and blade tensions.

[jaCK HobsonParticipant @jackhobson50760]

Don’t worry about heat from angle grinder slitting disk – you are going to heat treat after anyway. Cut oversize and file or belt grind to final size?

Get a decent belt grinder. 1HP per inch of belt, 2 inch wide belts are most common for grinding blades, longer belt the better.

I have a Fermi metal bandsaw – brilliant. 3mm O1 no probs. I don’t use any cutting oil.

Plasma will need more cleaning up I think? And creates a hard surface so would need belt grinder to finish.

Shear – no unless it is truly industrial.

I want a surface grinder!

 

[jaCK HobsonParticipant @jackhobson50760]

Obviously, annealed O1 is assumed! Hard 01 needs grinding.

[bernard towersParticipant @bernardtowers37738]

My hacksaw will allow the blade to be turned 90deg!

[Steve355]

On Steve355 Said:

Yes, an 8 inch cut with a hacksaw is well beyond the throat of the saw (and takes ages).

You are aware that you can turn the blade 90 degrees? I only ask because I’ve seen so many people trying to cut further than the throat of the saw that are unaware of this.

[Tony Pratt 1Participant @tonypratt1]

Guided hacksaw or band saw I should think is the best option. A bench shear sounds more trouble than it’s worth.

Tony

[John HinkleyParticipant @johnhinkley26699]

Steve,

If you have a requirement for a number of blade blanks, have you given consideration to water jet cutting?  I’ve not had need of it personally, but the process allegedly leaves a very accurate and clean edge.  There maybe a firm local to you who can do it for you, maybe tacking it on to another job.

John

 

[File HandleParticipant @filehandle]

I would also just turn the hacksaw blade through 90 deg. Also by sawing at a very shallow angle you can also go deeper than the frame suggests.

[Steve355Participant @steve355]

Thanks for all suggestions about the hacksaw, the hacksaw is nothing like accurate enough, and one has to saw through about 16 inches of tool steel for each plane blade. It’s not really a realistic proposition. It would be okay for one or two. But I seem to make quite a lot of them.

[DiogenesParticipant @diogenes]

I don’t understand how it’s moving on the mill – what kind of clamps/set-up are you using?

[Steve355]

On Steve355 Said:

It would be okay for one or two. But I seem to make quite a lot of them.

If you have a few to do, superglue three or four blanks together, put a fence on the bandsaw and run them through it. It will be faster than doing them one by one.

Raise the lower guide and drop the upper guide on the bandsaw so the minimum amount of blade is exposed between the bearings.

The waterjetting is also a good idea as you can nest the parts so you make more efficient use of your material (you can work out the gross area of steel you use for one item at present. Nest two together in an alternating pattern and the gross area will not be double).

 

[Tony Pratt 1Participant @tonypratt1]

Steve355, OK so you don’t like the hacksaw/bandsaw route as being too inaccurate so you do need to mill the blades, I don’t know your available machines but a horizontal mill is a fair option, set up a fixture for repeatability and cut through in one go for the long leg, use coolant as required or use a vertical mill with carbide cutters OR try the water jet option.

Tony

[Steve355]

On Steve355 Said:

the hacksaw is nothing like accurate enough

Set the tension on the blade correctly and it’ll cut as accurate as you are capable. This is another thing that people fall down on.

If your arm is getting tired then get down the gym, or use it to pick up the phone and ring a place that does Waterjet cutting.

[Mark RandParticipant @markrand96270]

The cut’s too long for a burke model zero or one in one pass, but an aluminium fixture plate fixed to the table slot allows you to mount a fence along the back , which can be dialed in to be as parallel to the X travel as you can measure. You can then clamp the work to the fixture plate, locating against the fence an do the cut with as many repositionings as you need. A moderately thin slitting saw with do the job perfectly well. You might have just a whisker to cut through by hand to  finish the corner, but it looks like a correctly located hole to cut towards will result in what you need.

The fixture plate can make the mill far more flexible, especially for our sort of work (often, really beyond the limits of the tools we can fit in the shed 🙂 )

[Steve355Participant @steve355]

Hi MarK

It’s a Burke #4. It can just accommodate an 8” cut with careful placement. I bought a piece of aluminium as suggested, but I had a couple of problems – no doubt my fault through having barely any experience with Aluminium. I made a fixture plate but struggled with tapping holes in it. The tapped holes somehow ended up loose and then the tap snapped off in one and… well it didn’t work.

I have a new piece of aluminium. I will make a new fixture plate, but I realised that making something that can secure a tang that is potentially only a few mm wide so it can be cut with conventional milling, isn’t an easy task. So for simple plane blades, if there is a shortcut method that doesn’t require the mill, it’s worth investigating it. I thought I could make a more generic fixture plate to make work holding on the Burke #4 generally easier.

[noel shelleyParticipant @noelshelley55608]

I know you have said the saw is not accurate ehough but I think you will be supprised at how accurate a disc can be and if let to cut at it’s ownspeed heating will not be an issue. The centrifugal force will keep the disc flat and aid keeping a straight line. Try it on a bit of scrap !  Noel.

[Michael GilliganParticipant @michaelgilligan61133]

It’s probably only “for inspiration” … but have a look at the Circular Saw attachment that Myford did for the ML7 etc.

http://www.lathes.co.uk/myford-saw-table/

MichaelG.

[Author]

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