Bench shear, cutting straight?

[Spark plug]

When I'm cutting sheet with the bench shear I struggle to follow a line as when I start cutting it screwed the material. I've tried different techniques but I don't seem to be able to stop it.

Is there a black art to the operation of these things?

 

[Windy Miller]

Very good question - I've wonderd this too!

 

[the artfull-codger]

They can be a little tricky to keep to the line sometimes, don't know your make ,I have a keetona which is a good quality british make & what I do is,if your metal is shorter than the bottom blade then it's easy to line it up with your line & cut, if the metals longer[as I suspect] then I nip it & sight along with the blades as best I can then start cutting with really short cuts keeping to the line till you get the cut the full length of the blades then you can take longer cuts [keeping your eye on the line of course] what I find is once you've veered off it's difficult to get back on track.

 

[Spark plug]

This is mine hear,

I suspect also it would benifit from the blades being re ground, but even on a cut shorter than the blades it's still a pain but more manageable.

 

[Wallace]

Do you get a clean cut or is there a burr on the edge? If there is too much blade clearance the material can be pulled into the blades in an arc as you cut as the shearing action is being lost.

 

[Paul.]

I do loads of cutting with a bench shear, there is a bit of a knack to it, but you need to have sharp properly adjusted blades, or they will drag and pull the sheet off the line, if cutting to a line its best to make a rough cut about 5mm away first then make the final cut, the thin offcut will then curl up out of the way of the bottom blade or can be twisted easily away,
If it has a hold down on the left side of the machine like the one below use it, it will keep the sheet flat to the blade for you and allow you to concentrate on following a line without wrestling with the job.

 

[Spark plug]

Yes it has a hold down, sounds like I need to get the blades sharpened up and set them up, I know blade gap ideally carts with the thickness of material being cut but what gap would be used for general cutting?

 

[Paul.]

10% of the material thickness for the blade gap,

 

[Mee]

Is there a black art to the operation of these things?

Good eye sight and the knack.

 

[droopsnoot]

I have this same issue with mine, I will have a look at the blade gaps and see if there's any sharpness issue. I did look at making some kind of "clip-on" arrangement with a piece of angle-iron to line up with the line of the fixed blade so as to make it easy to see the far end for longer cuts, but never got around to it.

 

[mike 109444]

I have this same issue with mine, I will have a look at the blade gaps and see if there's any sharpness issue. I did look at making some kind of "clip-on" arrangement with a piece of angle-iron to line up with the line of the fixed blade so as to make it easy to see the far end for longer cuts, but never got around to it.

Someone did mention he was setting up a laser line to project the cutting line BUT he was poo pooed for his ideal (not me I hasten to add) I did think it a good ideal as where I have mine set up, as I pull down to cut it does get a bit shadowed!
Maybe a laser line unit form one of the many levels/chop saws or even tape measures that have them in could be used. Won't cure the pulling but may make for better correction whilst cutting.

 

[droopsnoot]

Light is also an issue for me - I was thinking of maybe fixing some bright LEDs either side of the blade as it seems that wherever I put a light I just cast different shapes and strengths of shadow. Laser line might be an idea if there's somewhere to mount it, and would less hassle than a 4' bit of angle iron sticking out from the bench as long as it couldn't be knocked off line, though I guess if it runs true along the fixed blade it should stay that way.