{"product_id":"cordless-rotary-pen","title":"Cordless rotary pen, three speeds","description":"\u003cp\u003eThe drill press holds the work still and brings the tool down. Sometimes you need the opposite: the work stays where it is and the tool comes to it. That is this.\u003c\/p\u003e\n\u003cp\u003eCordless, 3.6 V, charged over USB from anything that charges a phone. 700 mAh cell inside. Three speeds - roughly 5,000, 10,000 and 15,000 rpm - stepped, not a dial, so you pick one and it holds it.\u003c\/p\u003e\n\u003ch3\u003eWhy three speeds and not one\u003c\/h3\u003e\n\u003cp\u003eSpeed is not power. On plastic and resin, high speed melts instead of cutting and you end up with a smeared groove and a ball of swarf welded to the bit. On steel, low speed just rubs and work-hardens the surface. The reason the tool has steps is that the right speed is a property of the material, not of how fast you want to be finished.\u003c\/p\u003e\n\u003cp\u003eEngraving glass or stone with a diamond point: slow. Cutting a slot in brass: fast. Sanding a printed part: slow, and let the abrasive do it.\u003c\/p\u003e\n\u003ch3\u003eWhat it will and will not do\u003c\/h3\u003e\n\u003cp\u003eIt engraves, grinds, polishes, sands, cuts small stock and drills. It is a pen, held like a pen, and that is its whole advantage - you can see what you are doing and your hand is where the work is.\u003c\/p\u003e\n\u003ch3\u003eWhere it stops\u003c\/h3\u003e\n\u003cp\u003eThis is not a Dremel and it does not pretend to be. A 3.6 V cell running a small motor has very little torque. Lean on it and it stalls; the correct technique is light contact and several passes. If you want to hog material out of steel, you want a mains tool.\u003c\/p\u003e\n\u003cp\u003eRuntime is limited by the cell, not by the motor. Continuous work will run it down, and it charges while it is not working, not while it is.\u003c\/p\u003e\n\u003cp\u003eCheck the collets it ships with against any accessories you already own before assuming they interchange. Shank sizes in this class are not standardised as tightly as the listings imply.\u003c\/p\u003e","brand":"Mikrabench","offers":[{"title":"Pen only","offer_id":47512708120767,"sku":null,"price":34.99,"currency_code":"USD","in_stock":true},{"title":"Pen with 50-piece accessory box","offer_id":47512708284607,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0760\/5826\/3743\/files\/S468f15d057f84355aea2d53f637885f6u.webp?v=1789873074","url":"https:\/\/arvonelle.com\/products\/cordless-rotary-pen","provider":"ARVONELLE","version":"1.0","type":"link"}