Oh no: another old favourite hand tool has gone electric without me noticing! Still sounds useful though, if they really are lighter than ordinary drivers. If they are quite cheap, y not just buy one and open it up: if the impact cams don't come out you still have a probably handy tool.
On the other hand you could experiment with a cheap drill and see how many extra volts you can put through it. For example, my cheapo 12v Wilkinson's job will take a 14v battery, when the 14v drill proves too big to fit in where I'm trying to drill...
I have a specific recurring job to do, reaming out short, small tubes of brass and I'm in need of a moderately fast, lightweight battery powered drill. Having hunted around a bit I've found that I can get drills that go up to around 1700 rpm - but they tend to be heavy 18V models ( typically
2 speeds with a gearbox that adds to the weight ).
Anything much lighter and faster costs a packet.
I've noticed though that impact drivers are typically small and light and run at speeds in excess of 2000 rpm - even quite cheap ones. Thing is, the impact part is a no-no - so does anyone know what the chances are of being able to strip down such a driver and 'lock' or disable the impact part of the deal?
Failing that, any pointers on a suitably fast and light drill that comes in under or around the £100 mark ( Dremel-type drills are unsuitable )?
Probably depends on just how small the bore of the tube is: like your dentist's drill goes v fast: the narrower the bit the more revs it has to do to get to the same speed.
How much torque do you need at that speed? The electric IDs will only switch to impact mode under moderate load. Lightly loaded they run like a normal drill.
The reamers, of which some are machine reamers and others are handmade variations on D bits, are all sub 3mm dia. Having used a 700 rpm drill I noticed a 1300 rpm drill did a much better job.
I don't need a great deal of torque - I'm using a series of reamers to step up from a 2.5 mm bore to 2.6 - but I can't afford to risk any hammer action should a reamer bind...although the work will be hand held, which might make a difference.
Why would the hammer action be a problem? (noting that the "hammer" is angular percussion and not linear). I would be surprised if you could stick enough load on a 3mm or smaller bit to get it to switch to impact mode.
For those sort of sizes, wouldn't a hobby drill be more suitable? Lidl did a pretty good cordless one recently which had a speed control. All the way up to about 20,000 rpm. ;-)
Reaming at 8mm on my lathe in bronze for making valve guides the optimum speed is between 200 and 300 rpm. Higher speeds lead to chatter and oversized holes and reaming should always be done slower than drilling. Pro rata that's 600 to 900 rpm for your 2.6mm reamers however like all machining it can boil down to suck it and see what works.
The work has to be hand held, so it's tolerant of a little movement - as I've found. The drills I've been using seem to have pretty decent chucks though.
I started off at 700 rpm, as per speed/feed charts but had very poor results, particularly with the D bit reamers. Boosting the speed to
1300 rpm made a huge difference, especially with the commercial mach>Why would the hammer action be a problem? (noting that the "hammer" is
See below!
I have a Dremel, but I looked at a cordless hobby drill. I really needed a trigger switch and a quick reverse function.
There's a need for 'speed of production'. I haven't noticed any chatter problems at high speed - in fact the bore of the tube seems to be smoother than running the tools at low speed.
I nipped into B&Q today - and as luck would have it they had a Ryobi display set up with a battery that actually had some juice in it. I tried the impact driver and found that it works exactly like a drill even when I apply considerable grip to the toolbit. On that basis I bagged myself a Hitachi impact driver that weighs in at a mere .9kg and goes up to 2300 rpm - and got 15% off the asking price too.
Tried it out and found that the hammer action doesn't kick in until considerable torque is required - certainly far more than the job in hand is ever going to present to the tool. Of course, it doesn't have a chuck - so I'll have to think about whether it's worth buying one of the chuck-adapters, or knocking up a set of collets.
But - so far so good...and if all else fails I've got meself a decent power screwdriver ( any old excuse ).
It's for upgrading the upper stack rod screw on certain saxes where the only thing that lets the horn down is excessive free play in that particular key stack. In order to make it a viable proposition, bearing in mind the cheap price of these things, I've got to get the job time down to 30 minutes.
Found out today that Trend makes a collet adaptor ( £3 a pop ) for hex-bit power tools, which should be a better bet than a chuck for accuracy.
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