I've got a couple of mini drills. These are very useful for grinding small items especially where access is tricky. The problem is that both are broken.
Firstly a Minicraft. This is a corded tool that has operates at 12v through a transformer. I'm sure that my brother gave this to me as a Christmas present many years ago. I've used it on lots of projects.
The drill uses a keyless check that consists of a ring to hold the spindle while the chuck is turned to tighten on the drill bit etc. This isn't a great design. It's not possible to get enough force using your fingers to tighten this sufficiently. I usually have to use two pairs of pliers.
The chuck has fallen apart with the ring detaching itself.
When sourcing a replacement the first thing to do is establish the thread holding the chuck. I measured the diameter at 8mm. The thread pitch was more tricky. I don't have a set of thread gauges so I took a macro photograph with the thread against a ruler. The pitch looks like 0.75mm.
The standard ISO metric thread in 8mm comes in 0.75mm pitch so this seems ok.
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| The new chuck |
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An
issue is that there is no way to tighten the chuck. This chuck lacks the ring
the original had. Some drills have a spindle lock to allow tightening but the
Minicraft doesn't. It might seem rough but I filed two flats in the spindle to
allow it to be held with a 7mm scanner.
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| And it all works fine! |
The next drill is a cordless one from Lidl under the Parkside name. It uses a collet rather than a chuck. The nut is aluminium and the thread has stripped. A chuck might be more useful so I looked for one of these.
According to a YouTube video the Parkside tool uses the same thread as Dremel ie 9/32" x 40 ME (Model Engineer) I measured the thread pitch it does seem to be 40 tpi (thread per inch)
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| "A commercial use of this standard does not exist" - you think? |
Will it fit? Will it work? - I'll know then the chuck wings its way to me from China.
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