Bench grinder advice please

[Anna Kettle]

I have some 4mm stainless steel threaded rod and the ends have become=20 burred when it was cut. I'd like to sharpen them up so the thread is=20 useable again

I'm looking at doing this with a bench grinder and I'd like comments on=20

a) Will this work or should I be doing it some other way? b) Would wet grinding a good feature for me / How much do I need to=20 spend? Screwfix pg 837 has one for =A312.99 (dry), two for =A339.99 (dry an= d=20 wet/dry). I assume that their =A389.99 bench grinder is over the top for=20 occasional use

Anna

--=20 ~~ Anna Kettle, Suffolk, England =20 |""""| ~ Lime plaster repair and conservation / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|

01359 230642

[Chris Bacon]

You could use a file, you know...

The cheapo will be fine for this. The £89.99 one is not suitable for your purpose. The "wet" one would be OK if you think it's worth the money "for occasional use".

[dom]

For small amounts of threaded rod, I'd use a bench vice and hand files. I'm a little suspicious of the "no name" tools from screwfix - I've sent quite a few things back that have verged on useless. Not quite so cheap, but I find Axminster's white range is ok

Nice pageting site!

[Guy King]

The message from Anna Kettle contains these words:

If you've only got one or two, us a file.

Better yet, don't get into this mess in the first place and put a nut on before you cut the studding. Then, once you've filed the end smooth you wind the nut off and it'll clear any remaning squiffyness in the threads.

[Dave Baker]

A sharp file and/or an oilstone will suffice or you can linish the burrs against a sheet of coarse wet and dry paper laid on a flat surface. Once you've got the end something like run a nut on and off it a couple of times to clean any final burrs up or if one end is ok run the nut onto that and all the way up and off the other end.

Before you cut threaded rod or a bolt always put a nut on and then run that back over the burrs to push them out before filing them clean. Aim for a very small chamfer all the way round the rod like a production made bolt will have.

Unless you really want a bench grinder I wouldn't buy one for a one off job although they are very handy tools for a variety of things. Sharpening shears, hoes, spades, lawnmower blades, wallpaper scrapers, chisels, lathe tools etc. I couldn't manage without mine but then I run an engineering workshop. Dry will suffice for any use you'll ever want. Wet helps keep the job cool and improves the surface finish on very critical work but most people manage fine with a tin of water next to the grinder. Take off a little stock, dunk the end of the item for a few seconds to cool it and repeat. If you grind for too long you'll blue the metal and weaken it. The bigger the item the less you'll need to do this because it'll act as its own heatsink. Very small things overheat almost instantly though. Just takes a bit of practice is all.

[Rob Morley]

Any cheapo grinder will be fine for occasional light use like this (I=20 think mine cost about =A315 many years ago from B&Q). But a decent small= =20 fine-cut triangular file should work fine for chasing out the groove in=20 the last bit of thread (depending on the grade of stainless).

[The Natural Philosopher]

Actually, buying a die for the thread and reforming it might be cheaper than a grinder.

BTW metal files will bounce off hardened steel shafts...grinding is the only way, or cutting.

[Mike Halmarack]

I sometimes rub them carefully against any handy bit of concrete.

[Anna Kettle]

Thanks for all your comments and I have tried out a few of them ...

Couldnt find a delicate enough bit of concrete so gave that up in favour of the triangular file which works fine but takes a few minutes per rod. I have several hundred rods to deburr :( Im now wondering if the grinding method will be any quicker especially as I might well have to finish them off with a file

So I'm looking favourably on the idea of buying a die for the thread and reforming it. I've never to my knowledge seen a die though. Screwfix don't list them so where should I be looking? I imagine that it comes in two hinged bits that wrap around the thread and the rod is then spun until the die falls off. Sounds ideal! Is that really how they work?

OK I should have put extra nuts on the rod before I cut it to help with the deburring. I will remember that for next time.

Anna

[Chris Bacon]

I should get a grinder anyway... it's likely to be much quicker, too. You probably won't need to "finish off".

Dies don't normally "wrap around". Here's a pretty picture of taps and dies (well, I like it!):

[dom]

Taps and dies at Screwfix ranging from cheap to works properly:

[Mike Halmarack]

instead of the cheapie.

[dom]

I bought some cheapie sash cramps rather than the Record ones. Regret it every time I use them.

[Rob Morley]

If you have a power drill that will run very slowly in reverse you can use that to hold the stud while passing the file over it a few times - saves having to file & turn, file & turn, file & turn ...

[Andy Hall]

One of the cheap ones would be fine for this application, Anna.

I wouldn't use one for sharpening decent tools unless you are prepared to change the grinding wheels for decent ones. These will cost as much as the cheap grinder.

A few words of wisdom....

- Safety goggles or glasses are a must.

- Work in a clean area and not one where there are combustibles around. It is a bad idea to do grinding in an area with sawdust on the floor or where flammable solvents are stored or used close by.

- A large pair of pliers to hold the rods

- Some water to quench them if they get too hot.

[Mark]

Both bench grinders and taps/dies are suitable as others have said, if this is a one off type job, a rubber backing pad

an elec drill with Disc also work, much cheaper.

-

[Chris Bacon]

It also works the other way around - don't work in an area where something (e.g. engine parts) might get contaminated with dust from grinding.

If they're long enough I'd say just hold them.

Make sure the rest is adjusted properly.

[Weatherlawyer]

You only need a saw file and a strong pair of glasses.

[Matt]

Also avoid grinding metal near any glass - especially car windscreens, windows etc. The embedded particles of grit and metal make a bit of a mess.

[Anna Kettle]

Now why doesnt the wrap around die exist? It would be so useful. Dies must have been invented by men

I will see if I can persuade my portable drill to run slowly in reverse, maybe by taping down the 'go' button. Dont think my wonderful SDS drill is suitable for this job :( and use it with the triangular file

Second choice is the cheap bench grinder - good safety comments Andy - I'd not have thought about flammable substances and there is a whole shelf full of them next to my workbench

Thanks all Anna