Cutting steel rod (16 mm) so it has a square end

[Alpha-Dave]

Hi all,

I’m wanting to make some ‘dogs’ and clamp-bases for a welding bench with 16 mm holes. My plan is to cut 16 mm round bar to lengths of about 20 mm, and then weld on a piece of 50x50 mm 8 mm thick flat bar. I need it to all sit square, and not have a weld bead around the base, so I’m thinking of drilling a 12 mm hole in the flat bar and filling with weld from the top.

That all sounds easy so far, but getting a square end on the cut rod would make it much easier (I think). A ‘metal lathe’ would be the ideal tool, but that’s not an option for me. I have an angle grinder, hacksaw and files.

I’m looking to make at least 10 of these, probably more as I add other jigs & fixtures. I can also see the need to make other metal bits ‘square’ in the future, so what I’m asking is: is it worth just cracking on with a hacksaw and files to square steel rod, or is it worth investing in a machine to do this? I’m space (and time, therefore skill) constrained, so I’m wondering if there is a better ‘ mechanical’ option that I have missed:
Something like a floor-sitting bandsaw would be nice, but not an option
An abrasive cut-off chop saw is an ok option, but not great; sparks, noise, smell etc. I would prefer to ‘cut’ than grind.
A cold-cut saw would be nice, but expensive
A ‘portaband’ would be nice, but expensive
An angle grinder in a sliding frame is an option, but I’m not sure how much better the cut quality would be versus a standard angle grinder.

So are there any good options for getting a nice, square cut on metal that I have missed?

Any thoughts appreciated.

 

[marcros]

My first choice would be to buy the 16mm cut to length. eBay sellers are usually willing to do this, even if they charge a few extra pence.

Alternatively, I would use my proedge belt sander because I don't have anything else suitable.

 

[novocaine]

how flat and how square. tolerances matter.
if it's flat enough and square enough then use a mitre box to cut with a hack saw and a square to check it.
if it's really flat and really square, use a lathe.

you could knock up a jig for filing to square if it helps.

you be better drilling and taping a hole then using countersunk fixing that spot welding them, no chance of warping the top plate.

edit to add: step away for the angle grinder. this is not the tool you are looking for.

 

[Ttrees]

Drill an accurate hole in some hardwood off cut/prepared timber for your round stock as a filing guide, if you cannot get a bit of it to stand straight on a precision surface, like even the stock of an engineers square.
Turning it around will show any errors.

Worth a thought on welding vs tapping, for customisation of those blocks in future.
You might want to make jigs for filing those blocks also.

I still think I am unsure of the question,
Since a metal lathe was mentioned I've gotta think precision,
Best maybe to answer some more things in order to tackle some possible accuracy issues.
Does the blocks need to be precise in all dimensions, is it from ground stock or rolled steel you are starting with?
Have you a drill which will give you the accuracy to drill for tapping later?
or would you be best filing all afterwards in a jig.

I am confused about the comment about a bead around the base?
I can't see the issue with this, as you would be surely grinding a big chamfer
around the rod so would have plenty of meat there for a bead, and have a structurally sound bench dog type thing.
I would be thinking that cutting and filing the square blocks to dimension will pose more of a challenge than cleaning up a bead on some round stock.

Were you thinking of ganging them up when made and filing to finish?
Tom

 

[Phil Pascoe]

I have the Lidl angle grinder holder/jig call it what you will. They're a bit of a trial to set up, but I can cut 30mm bar square and clean so I've a cheapo angle grinder set up permanently. This type of thing -
https://www.ebay.co.uk/i/2545235140...xufFPkXEdyUy3_bjB7aikaVfrlkFQNtEaArisEALw_wcB

 

[Spectric]

Hi there

Why does it need to be cut square? Drill a hole in the base plate, insert the 16mm pin into the hole, make it a tight fit and do not make it flush on the rear but leave enough space to fill with weld and if the weld does protrude just grind/sand flush. You now have a pin in the plate square and with no weld bead at the base.

 

[Boatfixer]

If you already have the bar and are in the gateshead area any time during the week you are welcome to use my cold cut saw. If you need to buy the bar Metal Supermarkets on Team Valley supply cut to size at a reasonable small quantity price.

 

[Alpha-Dave]

My first choice would be to buy the 16mm cut to length. eBay sellers are usually willing to do this, even if they charge a few extra pence.

Alternatively, I would use my proedge belt sander because I don't have anything else suitable.

Noted, I often buy cut-to-length, but also like having spare stock on hand in case I need something.

I also have a pro edge, I hadn’t considered using it to square off this material.

 

[Alpha-Dave]

how flat and how square. tolerances matter.
if it's flat enough and square enough then use a mitre box to cut with a hack saw and a square to check it.
if it's really flat and really square, use a lathe.

you could knock up a jig for filing to square if it helps.

you be better drilling and taping a hole then using countersunk fixing that spot welding them, no chance of warping the top plate.

edit to add: step away for the angle grinder. this is not the tool you are looking for.

Agreed that an angle grinder is not great here. I think that welding will be ok; I’m TIG welding rather than Stick or MIG.

I’m thinking a filing jig makes sense.

 

[Alpha-Dave]

Drill an accurate hole in some hardwood off cut/prepared timber for your round stock as a filing guide, if you cannot get a bit of it to stand straight on a precision surface, like even the stock of an engineers square.
Turning it around will show any errors.

Worth a thought on welding vs tapping, for customisation of those blocks in future.
You might want to make jigs for filing those blocks also.

I still think I am unsure of the question,
Since a metal lathe was mentioned I've gotta think precision,
Best maybe to answer some more things in order to tackle some possible accuracy issues.
Does the blocks need to be precise in all dimensions, is it from ground stock or rolled steel you are starting with?
Have you a drill which will give you the accuracy to drill for tapping later?
or would you be best filing all afterwards in a jig.

I am confused about the comment about a bead around the base?
I can't see the issue with this, as you would be surely grinding a big chamfer
around the rod so would have plenty of meat there for a bead, and have a structurally sound bench dog type thing.
I would be thinking that cutting and filing the square blocks to dimension will pose more of a challenge than cleaning up a bead on some round stock.

Were you thinking of ganging them up when made and filing to finish?
Tom

I have welded round stock to plate, but always fill with a fillet, even if chamfered. These will be going into a welding table that is essential an MFT style but with 16 mm holes, so I can’t have any weld protruding from the join. I’m thinking that cleaning any excess off would be more effort than just welding from the top.
These will be used as stops/dogs, but also to then weld clamps on to for positioning.

For the level of accuracy I need, I think the filing guid you describe is what I need. I can drill a 16 mm hole in the end of a wood block, then drop the hack-sawed rod in, and mark where an even height would be, or file in situ if I can clamp the rod there.

 

[Alpha-Dave]

I have the Lidl angle grinder holder/jig call it what you will. They're a bit of a trial to set up, but I can cut 30mm bar square and clean so I've a cheapo angle grinder set up permanently. This type of thing -
https://www.ebay.co.uk/i/2545235140...xufFPkXEdyUy3_bjB7aikaVfrlkFQNtEaArisEALw_wcB

Hi Phil, I was considering this sort of jig, but they look a little flimsy. I’ll take your word that they work ok. As for buying a solution, I have now found that Evolution Rage4 is only £99 at screwfix, which is remarkably cheap for a cold cut saw, so I’m now considering one of those.

 

[Torx]

I’d just cut them roughly to length and try a few local machine shops to face them off (the scruffier looking the premises, the more likely they will be to help). A tenner or a 6 pack of Stella would do it.

 

[Alpha-Dave]

Hi there

Why does it need to be cut square? Drill a hole in the base plate, insert the 16mm pin into the hole, make it a tight fit and do not make it flush on the rear but leave enough space to fill with weld and if the weld does protrude just grind/sand flush. You now have a pin in the plate square and with no weld bead at the base.

I need the plate to sit flat on the table when the pin is in the hole. I think from what you are describing would either need good clamping, or to use the holes in the bench itself as an alignment tool.

Given that I will be drilling ~30x 16 mm holes anyway, 8 or so more is probably reasonable. That could work well. I might end up doing this in a few different ways and compare the results.

 

[Alpha-Dave]

If you already have the bar and are in the gateshead area any time during the week you are welcome to use my cold cut saw. If you need to buy the bar Metal Supermarkets on Team Valley supply cut to size at a reasonable small quantity price.

Thank you for the kind offer. I’m currently going to TIG welding evening classes at the Gateshead College automotive centre on Team Valley, although next week is cancelled for half term. I’m now thinking that I can just get this done this weekend If it takes me longer to hacksaw and level than is reasonable then I will take up your offer, thank you. Otherwise I will post some pics this weekend.

 

[Alpha-Dave]

I’d just cut them roughly to length and try a few local machine shops to face them off (the scruffier looking the premises, the more likely they will be to help). A tenner or a 6 pack of Stella would do it.

Good point. I had considered getting someone with a mill or lathe to clean up the saw cuts for me, and there are a few people at my woodturning club (Wear Valley) who have metal lathes who I’m certain would do it for a small in kind donation. However I like the idea of being able to do something myself even if it is a bit slow.

 

[Torx]

If you can mark it square (do you have a vee block? and a sheet of glass or something ‘close enough’ to flat?) you can file it square. Machinists would have to do similar tasks as apprentices before they were allowed anywhere near the lathe.

 

[Peri]

Im not sure you understood Spectrics reply. (Or maybe we dont understand the problem ! )

I'd do it like he suggested to

 

[Phil Russell]

A trick I use that has not been mentioned is to put a broad jubilee clip around the rod to act as a saw guide if using a hacksaw. Or, mount in a vice and use the ends of the jaws as a guide ... checking the rod is square with a spirit level.
Cheers, Phil

 

[nick d]

Hi
I have an evolution rage saw and that will cut steel accurately like its butter. Might be worth a look, there are many size /price options
Cheers
nick

 

[Keefy.]

Spectric & Peri have it!
Use a cut off disc in your angle grinder, you'll get it true enough with a little care.
I can't see you dribbling weld into a 2mm gap from the top (ie if you go for the 12mm hole and 8mm rod idea) and you have the added complication of trying to keep it true.
Edit. Phil russels trick works too.
Just my six pennerth!