To grease or not to grease? - SDS drill bit

[Wuffles]

Yeah, but the question still stands. My exact same model Bosch is still going strong after possibly more years than this guy's, never once greased it.

 

[tackdriver]

I just had my SDS hammer drill eat the end off a chisel bit. I think not enough grease caused too much friction on the back of the bit, and it disintegrated leaving a chunk of metal in the chuck. I'll be using a bit of grease from now on.

 

[skelph]

Back in the days when our masons/brickies used a big Kango we used to dip the end of steels into a can of graphite oil before inserting them in the chuck. That stopped the steels from jamming in the chuck and also seemed to make things work much smoother- a quick wipe with a cloth cleaned off any muck before we applied the graphite oil.

skelph

 

[Beau]

Why would you not grease the bit? The poor thing is rattling back and forth in the chuck god knows how many times a minute. Leaving just masonry dust as a lubricant for the bit and chuck just seems brutal.

 

[Phil Pascoe]

I suppose there is an argument that the oil or grease actually catches the dirt and grit and turns it into grinding paste.

 

[Beau]

I suppose there is an argument that the oil or grease actually catches the dirt and grit and turns it into grinding paste.

Not one I buy in to then

Dust gets everywhere anyway so better with some lube IMO. The manufacturers recommended it and supply it for a reason. I was a bit lax about it at one stage with my Makita Supermac and knackered the chuck. Been more careful with the new chuck and had no bother. Mind you I used it one hell of a lot during our house build. Making openings through 600mm thick granite walls is a tough ask and probably put the drill through more use than many would see in a lifetime.

 

[Phil Pascoe]

Making openings through 600 thick granite walls is a tough ask and probably put the drill through more use than many would see in a lifetime?

I had to use an extension on a metre long bit for some of mine. I must admit I always clean and grease mine.

 

[memzey]

I always clean and grease my sds bits too. The important thing to note is that you should always use grease which will not rot the rubber seal at the end of the chuck - the thing which incidentally is there to keep dust out of the mechanism.

 

[Bill Derr]

Very timely that this thread surfaced, for a while I have been having trouble getting bits into my Bosch cordless sds chuck and wondered if it should be lubricated (never done it before) did a load of holes into the ceiling of a church crypt recently and it was showered with stone dust for several days, some must have got into the chuck and clogged it up a bit. I mentioned it to the sparks on the job and he suggested using a ptfe spray.

 

[AES]

Yup, interesting thread. I'm no tradesman, but have a "little" (so I'm told) Blue Bosch SDS hammer drill. I've done quite a lot with the first one (a lot of granite/concrete in my cellar) and after about 12 years the chuck packed up. The tool store replaced it (the whole drill) with a new model at slightly reduced price but also pointed me at the Manual which mentions greasing (the chuck end) with moly grease - not supplied.

I've done that since then (just a little rubbed on with the finger, rubbed off on a rag afterwards) and had no trouble since - AND I have just a "feeling" that the drills do cut a bit quicker. Perhaps run a bit cooler too (though still B-----y hot after a couple of 10 mm holes).

FWIW

AES

 

[RossJarvis]

I have a small bottle of Makita SDS grease in my drill case. I got it when I had my first bit stuck in the chuck. Every few months I dip a bit in and stick it in the machine. It works a treat. Ialso do the same with my impact drill. If you've never had a bit stuck in the chuck you won't know how difficult it can be to get the b*****s out. Nut drivers and the like, which have a high torque loading show up the issue. There's practically no danger of grinding paste effect as nothing moves against anything in these chucks apart from when you change the bit. In terms of cost/volume it's a stupid price but you'll never need much and certainly never need it for every bit change. Think of it like Coppereazing your wheel nuts.

 

[Trakehner]

Greasing it reduces wear on the main shaft. The SDS hold mechanism itself is pretty simple with a ball (like those in a bearing) that is kept in place by a spacer and a spring. The ball can wear (and will indeed) but on most tools the whole chuck assembly is very cheap and easy to replace at home. The only one I`ve seen with a really pricey chuck was a Metabo KHE24. I did take it apart and its like all other chucks, no idea why it costs so much.

 

[Eric The Viking]

I just found the instructions for my ancient Makita HR2400. They're dated June 1995! I really ought to get round to reading them properly one day...

... but it says this about grease:

Bit Grease
Coat the bit shank beforehand with a small amount of bit grease (approx. 0.5-1.0g). This chuck lubrication assures smooth action and longer service life.

For a long time (probably 15 years) I did nothing of the sort. I used it with conventional SDS bits up to about 22mm (for plumbing), and a couple of chisels (aside: worth keeping these as sharp as possible on a grinder - vastly reduces the effort needed in use), and diamond core bits up to 120mm diameter. It's occasional amateur use, but intense when there is a job to do.

It got loaned to a friend working on a church rebuilding project, and came back ridiculously clean, but with everything greased. This isn't entirely helpful, as it now has the propensity to spit said grease out (and if the chuck is rotating it goes anywhere/everywhere you don't want it to, for example onto bare plaster - it's not always being used for demolishing Roman ruins!).

I can't tell if it makes an operational difference, except that I can no longer just put the bits down anywhere I feel like it (they haver to go on old newspaper), and they pick up brick dust in a manner similar to iron filings and magnets. The latter really can't help any wear on the chuck! And I have to either wrap the chuck in sticky tape, or shove a yoghurt pot or similar over it, to catch the ejecta.

So Makita says "grease" unambiguously, but in practice it's a confounded nuisance.

... Hmm. I just realised I probably haven't contributed much to the discussion (Plus ca change).

E.

 

[Mark A]

I give my breakers' steels a generous dollop of grease every time as it seems to make them more efficient, but when it comes to my SDS drills I'm more conservative with the grease. If I'm only drilling I don't bother as there's enough in the chuck already, but for chiselling I always dip the bits in the pot first.

One thing I always do is clean up thoroughly after use, and whenever I swap between bits I wipe the shaft with a paper towel to remove dust and relubricate if necessary.