Sharpening Rotabroach/ Annular cutters

[James1979]

Has anyone made their own jig/ sharpener for these? Had a quick search but couldn’t find anything. I know they’re almost disposable as it’s about £15 to sharpen them vs £25 to buy plus all the waiting about but it’d be handy to accurately sharpen my own.

I do them at the moment with a bench grinder and they’re good enough but I’d like a better way of doing it. I’ve seen the various magic contraptions on eBay but would rather not buy one unless someone can actually recommend one they have.

Thank you

 

[mike os]

Given the time it takes is it really worth the effort?

 

[roofman]

Has anyone made their own jig/ sharpener for these? Had a quick search but couldn’t find anything. I know they’re almost disposable as it’s about £15 to sharpen them vs £25 to buy plus all the waiting about but it’d be handy to accurately sharpen my own.

I do them at the moment with a bench grinder and they’re good enough but I’d like a better way of doing it. I’ve seen the various magic contraptions on eBay but would rather not buy one unless someone can actually recommend one they have.

Thank you

If you keep them well lubed when using then i have cutters that have cut hundreds of holes and still are sharp as new...You have kinda answered your own dilemma. Unless you have time to burn and only you know how much your time is worth but me personally would not bother trying to sharpen an annular cutter after its life has ended

 

[Pete.]

I've sharpened loads. Work hand them out to monkeys who drill steel plate but run them into the concrete behind and blunt them. I use my Clarkson grinder. The time spent isn't so bad if you do a few at a time. I set one angle, grind all of them at that angle then set the next and do another round.

 

[James1979]

I've sharpened loads. Work hand them out to monkeys who drill steel plate but run them into the concrete behind and blunt them. I use my Clarkson grinder. The time spent isn't so bad if you do a few at a time. I set one angle, grind all of them at that angle then set the next and do another round.

This is the kind of thing I was looking to do. Get a few done at once and it isn't so bad. I'm also looking to extend the life of them. While we're not exactly cut off here sometimes things take a while to get if they're out of stock. I waited 2 weeks for a 22mm long series cutter just a couple of months back.

My thinking also was that id save a bit of cash by making them last longer

 

[Revs1972]

Takes me back around 20 years ago when a guy used to come round work and collect them, sharpen them then bring them back. Think he used to charge around a fiver each. Pretty sure he was a postman from memory who did it in his spare time

 

[frank horton]

I got one of those very thin red grinding wheels used on a Chain saw sharpeing machine........
I use that by hand......plenty good enough.......so it only cuts on 5 of the six edges......!!!!!!!
just takes a min to sharpen.......
usually get 5 -6 sharpenings before I bin them......

 

[gaz1]

my sharpener can do it

so can a quorn tool cutter grinder

your milling machine can also do it as well

 

[Brad93]

You need a tool and cutter grinder

 

[James1979]

You need a tool and cutter grinder

I’d love one. Need to get three phase sorted first. Mill isn’t running at the moment because of no power supply. Think I’ll go vfd route....

there was an old guy who used to collect them from a place I worked a few years back in England and bring them back a few days later. I think he used a quorn. Only seen one for sale at a reasonable price and dithered too long and it was sold.

 

[123hotchef]

my sharpener can do it

so can a quorn tool cutter grinder

your milling machine can also do it as well

how can you sharpen them on the mill? I have a fair few blunts ones. might be a nice winters evening job with a beer or 2

 

[Munkul]

I don't see the point, as if you look after your own cutters and use lots of lube, they last virtually forever. I've used one 22mm cutter for literally 500 holes and counting. Similar for 18mm and 14mm.
A new raptor 22mm is £20 and they're the best cutters on the market IMO. I have all the sizes I need, and maybe have to buy 1 new cutter per year.

I'd understand it if you're using them in less than perfect conditions, or if you're giving them to the monkeys, though.

 

[Brad93]

Cutters are only blunted by not using Lubrication, pushing too hard or not hard enough, or more commonly, lack of rigidity. Either a bad magnet or the steel your stuck to is too thin.

 

[123hotchef]

I don't see the point, as if you look after your own cutters and use lots of lube, they last virtually forever. I've used one 22mm cutter for literally 500 holes and counting. Similar for 18mm and 14mm.
A new raptor 22mm is £20 and they're the best cutters on the market IMO. I have all the sizes I need, and maybe have to buy 1 new cutter per year.

I'd understand it if you're using them in less than perfect conditions, or if you're giving them to the monkeys, though.

I have some from a job lot that are blunt. I look after all of the ones I purchased new though

 

[Munkul]

I get it, if you already have some form of tool/cutter grinder All I'm saying is it's probably not worth the cost of buying a grinder, learning to use it and storing it, for a couple of cutters per year.

Maybe someone on this forum would like to start a part time business? To be fair, I'd probably get a couple of my bigger/older cutters touched up at £10/cutter! I couldn't justify any more than that, though!

 

[Brad93]

£10 a cutter wouldnt even cover the time cutting 2 teeth let alone 4+

 

[Hitch]

Usually charge by the flute, bigger the cutter, the dearer to have sharpened.
They don't last forever.
We always had a box, any that are a bit dull and inefficient chuck them in. When there's enough just send them away.
Week turn around roughly. That relies on you having plenty of others to use in the meantime.

 

[123hotchef]

ill try with a diamond file i think

 

[Brad93]

ill try with a diamond file i think

You'll get chatter. Every tooth needs to be an even height

 

[Kram]

Never tried these but I'll say that my reground drill bits cut much nicer than new ones. Doesnt take long to do so its worth while in my opinion.

Have a 39mm cutter that geels sharp, but may be blunt, chatters far too much, or lathe may not have the rigidity for it. Im tempted to blunt off half the teeth to reduce the cutting forces and allow a better feed rate.