{"product_id":"summa-500-9891","title":"Summa 500-9891 Perforation Knife, 8 TPI","description":"\u003cp\u003eThe \u003cstrong\u003eSumma 500-9891\u003c\/strong\u003e is a perforation knife for \u003cstrong\u003eSumma\u003c\/strong\u003e cutting systems. 8 teeth per inch, with 0.067 in (1.7 mm) cuts and 0.067 in (1.7 mm) gaps, and a max cutting depth of 0.043 in (1.1 mm).\u003c\/p\u003e\n\n\u003cp\u003eSold individually.\u003c\/p\u003e\n\n\u003c!--specs--\u003e\n\n\u003ch3\u003eWhat is perforation cutting?\u003c\/h3\u003e\n\u003cp\u003eA perforation knife cuts a line of short slits with uncut gaps between them. The material stays connected along the line, then tears cleanly by hand. Use it for tear-off tabs, fold lines, and pieces meant to separate later.\u003c\/p\u003e\n\n\u003ch3\u003eFine 8 TPI pattern\u003c\/h3\u003e\n\u003cp\u003eThe 500-9891 is the finest of the Summa perforation knives we carry. Equal 0.067 in (1.7 mm) cuts and gaps give a tight perforation that tears easily and leaves a clean edge, at a max depth of 0.043 in (1.1 mm).\u003c\/p\u003e\n\n\u003ch3\u003eCommon questions\u003c\/h3\u003e\n\n\u003ch4\u003eHow do I know this fits my machine?\u003c\/h4\u003e\n\u003cp\u003eThis is a Summa part, number 500-9891. If you are not sure your Summa takes it, send us your machine model and we will confirm before you order.\u003c\/p\u003e\n\n\u003ch4\u003eWhich perforation knife do I need?\u003c\/h4\u003e\n\u003cp\u003ePick by how easily the line should tear. The 500-9891 (8 TPI, 0.067 in \/ 1.7 mm cuts) tears easiest. The 500-9892 (4 TPI, 0.118 in \/ 3 mm) and 500-9893 (3 TPI, 0.197 in \/ 5 mm) leave longer cuts and gaps and cut deeper, for a stronger line.\u003c\/p\u003e\n\n\u003ch4\u003eHow do I know when to replace it?\u003c\/h4\u003e\n\u003cp\u003eWatch the perforation. Teeth that no longer cut through, uneven slits, or a line that tears raggedly instead of cleanly all mean the knife is worn.\u003c\/p\u003e\n\n\u003ch3\u003eGetting the most from your cutting table\u003c\/h3\u003e\n\u003cp\u003eA fresh blade is a good start. But if you are going through blades faster than expected, or cut quality has become inconsistent, the blade is rarely the whole story. Cut depth, speed, pressure, and machine condition all affect how long a blade lasts and how clean it cuts.\u003c\/p\u003e\n\n\u003cp\u003eIt is worth asking: When was your machine last serviced? Are your parameters dialed in for this material? Is this the right blade geometry for what you are cutting? Could your operators use time with someone who runs these machines every day?\u003c\/p\u003e\n\n\u003cp\u003eFlatbed Tools offers machine service, preventive maintenance, operator training, and workflow consulting. If something is not cutting right, reach out. We have probably seen it before.\u003c\/p\u003e","brand":"Flatbed Tools","offers":[{"title":"Default Title","offer_id":46417078550572,"sku":"SUM-500-9891","price":350.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0343\/5259\/4988\/files\/FBT_IG3_1_2.jpg?v=1738012037","url":"https:\/\/flatbedtools.com\/products\/summa-500-9891","provider":"Flatbed Tools","version":"1.0","type":"link"}