# Twist Drill Bits DeWalt DT4939 HSS-E Cobalt 8.5 mm — pack of 10 **URL:** https://aio.lv/en/product--dewalt-dt4939--10538801 **Data updated:** 2026-03-07 17:52 (EET) **Category:** Drill Bits **Manufacturer:** DeWalt **Manufacturer code:** DT4939 **EAN:** 5035048534908 **Warranty:** 2 Years **Availability:** Available for order **Price:** 63.49 € **Prices and availability valid until:** 2026-07-15 23:59 **Price without VAT (21%):** 52.47 EUR **Can be purchased by legal entities:** Yes (invoice) **Buy:** https://aio.lv/en/product--dewalt-dt4939--10538801 ## Delivery options | Delivery method | Delivery time | Cost | |---|---|---| | Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 06.07.2026 | free | | Pickup points | 09.07.2026 | 1.99 EUR | | Courier delivery to door | 09.07.2026 | 4.99 EUR | ## Summary description Set of 10 DeWalt DT4939 HSS-E cobalt twist drill bits with an 8.5 mm diameter. Designed for drilling in hardened steels and metal materials where cobalt alloyed high-speed steel (HSS-E) provides increased heat resistance and wear life. Suitable for use in hand drills and drill presses for metalworking, maintenance, and industrial fabrication tasks. ## Long description Set of 10 DeWalt DT4939 HSS-E cobalt twist drill bits, 8.5 mm diameter, supplied as a pack for metalworking and industrial tasks. These high-speed steel (HSS-E) drill bits contain cobalt alloying to increase hardness and heat resistance, making them suitable for drilling hardened steels and other metallic materials. The 8.5 mm size is useful for creating medium-diameter holes in maintenance, fabrication, and workshop operations, and the bits are compatible with standard hand drills and drill presses. Advantages The DeWalt DT4939 HSS-E cobalt drill bits offer improved wear resistance and higher red hardness compared with standard HSS bits due to the cobalt content, extending cutting life during prolonged or high-temperature drilling. Their twist geometry provides efficient chip removal and stable centering when drilling through metal. Supplied as a set of ten, the pack ensures consistent replacements for repetitive tasks and reduces downtime during production or repair work. Suitable for Drilling hardened steels and alloy steels Metal fabrication and workshop drilling Maintenance, repair and overhaul (MRO) operations Use with hand drills and drill presses for medium-diameter holes Key specifications Material: cobalt-alloyed high-speed steel (HSS-E) Diameter: 8.5 mm Pack quantity: 10 pieces Tip type: twist drill geometry for metal cutting Intended use: drilling in steels and metal materials How to use Secure the drill bit in the chuck of a hand drill or drill press and tighten firmly. Select an appropriate cutting speed and apply steady feed pressure; for hardened steels use lower speeds and steady coolant or cutting fluid to reduce heat. Mark and center-punch the drilling location before starting to ensure accurate positioning. Withdraw the bit periodically to clear chips and, when required, reapply cutting fluid to maintain tool life and hole quality. Usage recommendations Use appropriate personal protective equipment, secure the workpiece, and select cutting parameters matching material hardness. For best results on hardened steels, use coolant and moderate feed rates; replace worn bits from the pack to maintain consistent hole quality and reduce risk of tool breakage. ## FAQ ### How much does the DeWalt DT4939 HSS-E Cobalt Drill Bits 8.5 mm, 10 pcs cost, and is it available for purchase? The price is 63.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 9 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance. ### If I order this product today, when will I receive my order? If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 06.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation. ### What payment options are available? AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay. All transactions are 100% secure and encrypted. ### Can this product be purchased for a company (with VAT)? Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout. ### What is the warranty period? All DeWalt products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized DeWalt service centers and through AiO.lv ### Can the product be returned after purchase? Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return. ### Where should I contact for warranty service? For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty ## Image https://aio.lv/img/cache/product/10538801/66731885_large.webp