The Flexbar Lexan Latheguard: Information And Specifications Hints, For Selecting The Correct Latheguard! The Chuck Diameter Being Used On Your Lathe Makes For A Good Formula. Utilize Dimension "A" And Other Dimensions Given In Chart Shown Below. On Lathes With Center Heights Of 7 Inches Or More There Is A Significant Variation In The Diameter Of A 3-Jaw As Against A 4-Jaw Chuck. It May Be Necessary To Install The Next Larger Latheguard To Accomodate For The 4-Jaw Chuck. Keeping A Double Bracket (No. 13071) On The Lathe Makes It Possible To Switch Your Latheguard From Small To Larger Size And Vice Versa, In One Minute. Neither Razor-Sharp Chips Nor Broken Tools Bits Will Penetrate The Lexan Shield.