Chinagraph Marking Pencils - Black (Box of 12) - Wax Pencils for Glass, Metal & Ceramic Marking - Ideal for DIY, Crafts & Industrial Use

If you can sharpen one of these without the lead breaking then you are a better person than me or my engineer neighbour. After sharpening 3 of them down to 2/3 of size, with each of them breaking at each time of sharpening, before use, I can only assume they were repeatedly thrown against a wall or dropped from height to assure they were useless. Instead of buying these, give the money to charity, becuse you will have just as many functioning pencils if you don't buy them!I bought these because they were quite cheap through the Amazon addon program. I wish I hadn't bothered, or at least read the reviews beforehand. You do have to be very, very careful sharpening these. And they don't write on anything that's even vaguely cold, wet, or curved. Also, if you try to write over a mark again, it erases the previous mark. Try writing an uppercase "H" without writing over the previous mark.All in all, I can chuck these in the bin.These are probably the worst chinagraph pencils I've experienced - and I've used hundreds over the years. No matter how little they are sharpened the "lead" drops out before or during first use. Three days of attempted use and the entire box of ten is almost gone. On the rare occasions it is possible to use them they do not mark on the laminated surface of the charts - which rather defeats the point. Ho hum, off to the stationer to buy my usual brand.Pens/pencils fade in the sun so I have to figure out what I’ve planted! These have solved the problem. Incidentally, I don’t understand some if the negative reviews. Maybe I’ve been lucky, but I’ve not had any of the described problems.Easy use and comfy hold ! Remember china graph pencils seem not to work if they get too cold so in winter keep them somewhere warmish not a cold shed . And won't work on frozen or icy items. Great at their job ! Will buy again