com. This groove can either be extruded, or machined using a special dovetail cutter which is available from Spira. You just position it according to where the groove should be and revolve around decired axis. . To overcome this problem it has been recommended that a dovetail groove be machined so that the O-ring is trapped by the converging sidewalls of the groove. 0159 2 3 4 2. Optional Retention Sleeve Material: D-2, 60-62 HRC Retention Sleeves for the DoveTail Cores assure the position of the molded part during core collapse and part ejection. Designed to the standards suggested by the O-Ring division of Parker Hannifin Corporations (tools meet both specs: ORD 5700/USA, ORD 5700) Designed for milling half dovetails or full dovetails with no drop hole allowance. Half Dovetail Groove. d. O ring size chart metric 554232-As568 o. Center cutting. As shown in above figure, an O-ring also gets compressed axially in a dovetail groove. Parker Hannifin2360 Palumbo DriveLexington, KY 40509Ph: 859-269-2351Fax: 859-335-5128 oesmailbox@parker. Check the diameter, wall angle, corner radius and O-ring. This paper covers the development and testing conducted to adopt the dovetail groove in the SAE standard. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent. AS568A-102 (left). It is sometimes necessary to mount an O-ring in a face type groove in such a way that it cannot fall out. The dovetail groove construction is only recommended for O-rings with bigger cross sections, . Dovetail cutters can create those o-ring grooves so that you can mill with a wide variety of tools. Round Internal Toolholder Selection Expands Thinbit, manufactured by Kaiser Tool Company, has expanded its selection of internal Groove ‘N Turn toolholders. Dovetail Cutters-Sight Groove Dovetail Cutters Solid carbide tool designed for milling dovetail grooves for Sight Attachments, and offered in 50° or 60° included angles. Polyurethane O-Rings Material. Products. 4-18 Parker Hannifi n Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 † Fax: (859) 335-5128 Static O-Ring Sealing Parker O-Ring Handbook For Internal Pressure (outward pressure direction) dimension the groove by its outside diameter (H ) and width: O (H ) = Mean O. 01 to 1. O-rings are circular sealing elements with circular cross-sections, and are mainly used in static applications. DSP Cable Groove; Solid Carbide, 1/8"Ø-1/4"Ø; Solid Carbide, 3/8"Ø-5/8"Ø; Solid Carbide, . (fig. S. comDovetail grooving inserts are used to machine O-ring dovetail grooves with 66-degree undercut angles. Bochnia. 030”, . THINBIT, manufactured by Kaiser Tool Company, has announced the expansion of its GROOVE 'N TURN line of dovetail grooving inserts. . O-ring Gland Design Dovetail seal Also here there is a metal to metal contact as long as the con-struction will not deform under system pressure. 5 Ø; Carbide Tipped; Corner Rounders. Produce. Recent Posts. Gland Design Dovetail Grooves Inches; Gland Design Dovetail Grooves Metric; Gland Design Static Axial Application; Gland Design Static Radial Application;This metric o-ring groove design reference guide will help you find the right radius, back-up, pressure and other o-ring dimensions for basic applications. The dynamic format is structured to support movement while still maintaining the seal. Free CAD downloads, quick delivery, competitive pricing, and no minimum order quantity. Special orders in 4-6 working days. Revision History Related Info. For static o-ring grooves. Proper sizing is key. The Parker handbook does not define the bottom (. The present invention particularly provides a dovetail groove sealing material which does not cause dropping from electric or dovetail grooves even when a sealing load or a thrust load is applied from both the left and right sides of the dovetail groove sealing material attached to the vacuum gate valve. The Deep O-Ring Loaded U-Cup design is a modified version of the Standard's square shape. ± w 0660-20 0670-20 0680-20 0690-20 0700-20 0710-20 0720-20 0730-20 0740-20 0750-20 0760-20 0780-20 0790-20 0800-20 0820-20 0830-20 0840-20 0850-20 0860-20 0870-20 0880-20 0900-20 0920-20 0930-20. Note: do not remove the part from the mill between making the fly-cut and milling the groove. FVMQ Fluorosilicone O-Rings Material. Neck diameter is measured to the theoretical sharp corner. (a and c) Fracture pattern of slit saw groove. For reciprocating O-rings: a compression ratio of 10-20%. The Standard O-ring groove is typically used in applications where there is a need for a static seal, such as in hydraulic systems. TO PLACE ORDERS OR QUOTATIONS O-Ring Cross Section Gland Depth Squeeze Diametrical Clearance Max. Need space in groove to allow for volume swell, thermal expansion, and increasing width due to squeeze. Solid carbide. . Undersized Cutter Design Allows Climb Milling Both Faces of Groove for Improved Finish. O-ring Groove Design in 3 easy steps: Step 1. Ultra Quick-Shield Product. Free delivery no minimum order. Ceetak O-ring Catalogue. Viewing 10 of Show More. 3. 0240" (. groove. Select a groove from the lists in the top left corner. This is beneficial for special applications where the O-ring has to be fixed by the groove e. Press-In-Place Seals. (ret) EX. For dovetail grooves, match the centerline of the groove with the centerline of the O-Ring. • To deburr use a Scotch Brite pad (a deburring knife will destroy the “W” tolerance). Sometimes, a bit of interference can be designed between the outer diameter of the O-ring and the outer diameter of the groove. A – 7 Introduction to O-rings A – 8 Installation Dimensions A – 9 General Tolerance Guide A – 10 O-ring Coatings B – Materials B – 1 Material Guidance. . Price Each . This trapezoidal groove shape is designed to hold the O-ring and keep it. There is no Industry Standard for these types of grooves. Whether you need O-rings or the glue for sticking an O-ring cord. Proudly made in the USA by AB Tools, Inc. 0840" Corner Radius: 0. Note: Not all standard sizes are in stock. Narrower groove for sealing vacuum or gas. EricHill, I regularly use half dovetail o-ring grooves. Dovetails have the significant benefit of allowing a commercially available O-ring to be used in an application. com to prevent the O-Rings from falling out of the Glands. 220 5. Cutters for machining grooves by side running have a dovetail groove shape. O-Ring Groove. Several alternative designs were considered before agreeing to adopt the dovetail groove. O‑rings. Groove Width. The right combination of x-ring material and x-ring groove design will maximize sealing performance life. Face seals can seal internal pressure, external pressure, or both. Learn about the factors that affect vacuum sealing performance, such as o-ring size, material, groove geometry, surface finish, and lubrication. I'm cutting a dovetail groove for a two inch diameter o-ring in 6061 aluminum. On the other hand, Super-O-Lube is an ideal all-purpose O-ring lubricant. 7 N/mm for 80 Shore A. O-ring standards are specified by the JIS B 2401 standard. THE O-RING EXAMPLE Throughout this guide, the o-ring is used as an example in our discussion of seal design principles. There are cutter shapes that machine the O-ring shape by plunging, and cutter shapes that machine grooves transversely. The dovetail groove described in Design Charts 4-4 and 4-5 will serve this function. 0700" Cutter Diameter: 0. 003 0. 015" 1: 2" 41062: $85. O. Inside is the circle of the corresponding o-ring which should be deleted or turned to construction geometry when. 1. The hoop stress of the O-ring causes it to rebound to its circular shape, not staying in the groove. Please call for specific lead times and availability of special sizes or materials. Our Carbide O-Ring Dovetail Cutters meet Parker Hannifin standards. If the groove design in illustration 4. The angled face must face to the inside of the groove for it to retain the o-ring when the o-ring is streched into the groove. Standard O-Rings 800. To facilitate assembly, the diameter of the O-ring groove is usually selected somewhat larger than the diameter of the O-ring. 33 mm thickness by 20 %, approx 5 N per mm of sealing length is required for a hardness of 70 Shore A resp. Adding to the challenges is the common use of difficult-to-machine materials solid Inconel 718 and cladded Inconel 625. This type of dovetail cutter tip is useful for machining female semicircle grooves of radii. 1-23) 2. Bosstail: The O-ring is used for sealing straight thread tube. E. Choosing the Geometry You Need Dovetails cutters can come in seventeen included angles to make sure you can cut your trapezoidal grooves to exactly the right angle required for your job. 015" 1: 2" 41062: $85. Male or Plug Seal design is based on the following factors (refer to fig. The dovetail groove described in Design Charts 4-4 and 4-5 will serve this function. ). • Encourages the shielding perfor-mance illustrated in the Shielding Quality data sheets. Volume fill is the O-ring volume divided by the gland volume. A drop-hole is an off-center hole. • Easy to use • PDF output • Saving of your designs Designed to the Standards Suggested by the O-Ring Division of Parker Hannifin Corporation (ORD 5700/USA, ORD 5700) Designed for Milling Full Dovetail Grooves with Drop Hole Allowance. The O-ring groove calculator enables engineers to specify an O-ring groove for any given O-ring or vice versa calculates the best suitable size O-ring for any given groove. If adequate squeeze has not been applied. P계열/ G계열/ V계열. tool # diameter minor dia groove depth top radius bottom radius flutes o-ring size shank dia overall length 1 pc 2-10 11-25 26-100; 51-8010: 0. Insuffi cient radius will potentially cause damage to the O-ring during installation, while excessive radius may contribute to. 005 0. Number O-Ring Size Neck Ø TSC Neck Ø Over R Slot Depth Top Rad. 5/8. D. Installation Damage. 1. 내경. To create a retaining-ring groove, click the Retaining Ring Grooves tab. Gland width is to sharp edge of groove. Of Flutes. 8 μm Ra) groove sides: X = 63 micro inches (1. Revision History Related Info. The online O-Ring Calculator offers engineers and professionals a quick and easy way to calculate O-Ring dimensions and the appropriate housing layout in accordance with the international O-Ring standard ISO 3601. 2. 0050" see more dimensions. Hydrogenated Nitrile HNBR O-Rings Material. A. TO PLACE ORDERS OR QUOTATIONS O-Ring Cross Section Gland Depth Squeeze Diametrical Clearance Max. The O-ring must have room to expand laterally in the groove due to axial compression. Calculate the O-Ring groove dimensions. This is an expensive grooveThe O-ring calculator tool is intended to form the basis of an o-ring installation, and assist with selection of o-ring and hardware dimensions. 070. We use Coordinate systems for referencing. 231 Then O-ring I. In the past all the o-ring grooves I machined were for static pressure using the Parker guidelines and the o-rings move around in those grooves. TheA Dovetail provides a retaining feature in a face seal gland. Dovetail grooving inserts are used to machine O-ring dovetail grooves with 66° undercut angles. Our O-Rings are both cost-effective and perform highly in almost every environment. For rotary O-rings: a compression ratio of 0-10%. Oring that needs to be milled into the face of a 6061 aluminum part (dovetail groove). NBR Buna-N O-Rings Material. O-Ring Compression (%) Groove Depth incl. for fluids. 40; Customer Rating: Find a DistributorO-Lube has a recommended service temperature of -20°F to 180°F (-29°C to 82°C). 052 . In order to seal properly, the o-ring has to deform in the application by being compressed and stretched in any number of ways. 5-30 Parker Hannifi n Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 † Fax: (859) 335-5128 Dynamic O-Ring Sealing Parker O-Ring Handbook Gland Dimensions for Industrial Reciprocating O-Ring Seals Groove Diameter (Rod Gland) Tolerance - . Lastly, the fourth table is for dovetail groove design. Part. A GO/NOGO is supremely helpful with Dovetail Grooves (when Milling). The seal assembly consists of an elastomer O-ring and a gland. for gases and 32 Ra max. 150” with major diameters starting at . For technical assistance with any of these alternate arrangements, please contact Dichtomatik North America. 1030" Cutter Diameter 0. X-rings are available in the same USA standard. Standard; Metric; Without Drop Hole; Half Dovetail; Lathes; Special Quote Form; Dovetail Cutters. Diamond Seals. 66° Dovetail Cutters For O-Ring Grooves. 2. 7745 (U. Standard; Metric; Without Drop Hole; Half Dovetail; Lathes; Special Quote Form; Dovetail Cutters. 020" Radius. Dovetail grooves are used to hold the O-ring in-place on a. 828. 6. of O. O-Ring Basics; Seal Types; O-Ring Elastomers; Static O-Ring Sealing. 125, the speed was 2760 rpm (the max for my machine), the depth is . After selecting a material that fits your sealing application, you can continue by having the Size Selector calculate the O-ring dimensions and tolerances, considering even thermal expansion and volume swelling of the sealing element. Proudly made in the USA by AB Tools, Inc. Availability: In Stock 5-10 days. 0940: 0. Parker O-Ring & Engineered Seals Division specializes in the design and manufacture of high-quality sealing solutions. $120. This is an expensive groove to machine and should only be used when absolutely necessary. Cutters for machining grooves by side running have a dovetail groove shape. Dovetail Groove: Half Dovetail Groove Parker Hannifin O-Ring & Engineered Seals 2360 Palumbo Drive Lexington, KY 40509 Ph: 859-269-2351 Fax: 859-335-5128 [email protected] in the smallest possible groove (i. Locations. For axial, radial and flange applications. And use preferrably 32Ra for groove surfaces and sealing surfaces, 63Ra works as well. com O-Ring Products. O-Ring inner diameter stretch, outer diameter squeeze. 005. C. D. Total clamping pressure on the O-ring due both to the effects of vacuum on the parts being closed, and the effects of bolts or clamps used with the O-ring, should be approximately 800 pounds per lineal inch of O-ring. An O-ring that is sheared, nicked or cut during installation can immediately cause leakage when placed into service. World Class; Certifications; Contact Us; Call Us: Seal & Design Canada: Toronto, Ontario (416) 741-7005 Toll Free: 1-866-242-3770 Headquarters: Clarence, NY (716) 759-3344 Higbee Division: Syracuse, NYAS568 -004 through -475 Dovetail Seal Design Guidelines: AS-568 DASH # W O-RING CROSS SECTION: G GROOZE WIDTH: H GROOVE DEPTH: R1 RADIUS: R RADIUS: SHARPEDGE: ROUNDEDEDGE: Inch +. A dovetail helps hold an o-ring in place during assembly (or shipping possibly) while allowing sufficient space for compression of the o-ring. The purpose of the tables below are to serve as a design guide for Dove Tail O-ring grooves using all AS568 O-ring sizes*. 4-18 Parker Hannifi n Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 † Fax: (859) 335-5128 Static O-Ring Sealing Parker O-Ring Handbook For Internal Pressure (outward pressure direction) dimension the groove by its outside diameter (H ) and width: O (H ) = Mean O. If you're talking turning ''true '' dovetail grooves i. Dovetail Cutters-Parker Hannifin O-Ring Dovetail Cutters WITHOUT Drop Hole Allowance. Sticking Phenomenon and its Causes 2-1）Sticking of O-rings When a rubber O-ring contacts with its opposing face, such as a metal surface, under pressure, it sometimes sticks to the face. Gaskets. 054. introduction - double chamfer seals and d-ring seals figure 1. Dovetail grooves are incorporated into a design to help hold the O-ring in place during installation and maintenance. 050 . Timelord (Mechanical) 15 Dec 08 16:29. m barnwell services: the uk’s largest independent manufacturer, stockist & distributor of o rings metric range ‘o’ ring size chart page 2 i. In the Expressions, you can make a list of which standard grooves you want to use, and list those in the UDF wizard. Dovetail grooves are used to hold the O-ring in place during installation or maintenance. , (800). 1. o-ring standard size (jis b 2401) table of dimensions of o-rings for static sealing of cylindrical surface and flat surface. Download the pdf to access tables, charts, formulas, and. g. 28: $63. 5 was of a standard face seal, the o-ring would fall out as the valve cycles up. 1/2. The insert design is optimized for strength by utilizing a left/OD and right/ID insert pair to generate the. . Read Next Five Common Mistakes Shops Make with ER Collets (And How to Prevent Them) World Machine Tool Production and Consumption Modestly Down in. . 70 - Double End Split Blanks. , at the hardware and O-ring tolerance stack-up) and the smallest possible O-ring in the largest possible groove. The groove design allows the O-ring to be retained in the face seal during assembly and mainte-nance. A straight groove of the size that would be needed to hold it in place firmly would have too small of a cross-sectional area and would extrude or possibly split the o-ring - most straight o-ring. No matter if you need metric or inch, standard or custom-made O-Rings – any size of O-Ring. For O-Ring Grooves for industrial applications. 66° Included angle, 24° per side. O-Rings. An undercut or dovetail groove has proven beneficial in many applications to keep the O-ring in place. Special orders in 4-6 working days. Cleanliness is key to a good bond, but usually the pits don't go below the line where the o-ring seals. Your o-ring will stretch as much as the groove ID is. Bore. 002 on the floor for the dovetail tool to finish the bottom and. 08 mm extension. 5 Ø; Carbide Tipped; Corner Rounders. When machining this groove, a standard o-ring groove must be machined first. The dovetail groove construction is only recommended for O-rings with bigger cross sections, . To retain them, you need to dovetail the groove (make it a trapezoid shape). 2 straight flutes. . O-ring Vacuum Seal Dovetail & Half-dovetail Grooves It is often necessary to provide some means for retaining an O-ring in a face seal groove during assembly and maintenance. It is sometimes necessary to mount an O-ring in a face type groove in such a way that it cannot fall out. Doing one in a groove that is less than 1/32" wide is extremely challenging. As well as the chemical volume swell or shrinkage of the O-ring. Adding to the challenges is the common use of difficult-to-machine materials solid Inconel 718 and cladded Inconel 625. 49 votes, 22 comments. 70 - Single End Split Blanks. O-ring dovetail cutters have an included angle of 48°. I would rough the groove width to the right size with an endmill and leave . Proper O-ring Face Seal (ORFS) fitting assembly and installation steps: Step 1: Inspect the tube end for a O-ring. com O-Ring Products. replace existing hydraulic packing and O-Rings without changing gland design. This groove design is relatively uncommon as it is expensive to machine and should not be used unless absolutely required. DSP Cable Groove; Solid Carbide, 1/8"Ø-1/4"Ø; Solid Carbide, 3/8"Ø-5/8"Ø; Solid Carbide, . Optimized with a corner radius profile for extended tool life and finished groove profiling operations, Micro 100's right hand retaining ring grooving tools are designed for use in bores . A hard thing to fix with dovetail grooves is the expansion issue. 46 - Thread Relief Tools. 53 - O-Ring Dovetail Groovers. 24° Per Side, 48° Included. Parker Hannifin O-Ring & Engineered Seals 2360 Palumbo Drive Lexington, KY 40509 Ph: 859-269-2351 Fax: 859-335-5128 [email protected] mm) Length of Cut 0. EZ-Lok Seals. Create dovetail grooves that allow O-rings to flex without falling out of place. Explore some of the most common sealing materials we offer here. 057. The O-ring is also axially squeezed in a dovetail groove. ; In the Grooves dialog box:. e. The top of the adapter is screwed and glued to the cast aluminum valve cover and the bottom rail will have the o-ring. To open this tab: Click Grooves (Toolbox toolbar) or Toolbox > Grooves. Gland Design for Static Application for O-rings with Axial Squeeze. Refer to the O-Ring Handbook or consult a Parker applications engineer for assistance in sizing O-rings to dovetail glands. a lid which opens regularly. X-Rings are designed for improved slow dynamic application performance. Many fluids can cause an O-ring material to swell 10 or 20%. Dovetail O-Ring Groove Design Learn More About Dovetail Groove Design for O-Rings . 2 or 3. Dovetail grooves are used to hold the O-ring in place during installation or maintenance. 057". You probably need. This is also the case when placing an item inside another item and utilising the o-ring as the final sealant. Finally,models and analysis. Surface Finish X groove top and bottom : for liquids X = 32 micro inches (0. 73 - Face Grooving Tools - Full Radius. Gland width is to sharp edge of groove. O-ring standards are specified by the JIS B 2401. Cutters for machining grooves by side running have a dovetail groove shape. The groove design allows the O-ring to be retained in the axial/face seal during assembly and maintenance. 059 102 . O-Ring Metric Groove Design [PDF] Seal & Design Company Info. Til now I allways used a normal tool to make a straight groove and then used two hand grinded ultra mini boring bars to make the 26° parts. The O-ring must have room to expand laterally in the groove due to axial compression. o リングの id または od は、以下のガイドラインに従って、干渉が生じるようなサイズにする必要があります。 ピストングランドシール: 取り付けられた o リングが常にわずかに伸びるように、o リングの id はグランドの外径より小さくする必要があります。O-ring grooves are high-speed steel or carbide cutters used for O-ring groove machining. , the THINBIT GROOVE ‘N TURN line includes Dovetail grooving inserts and Static O-Ring Grooves. A square O-ring prevents these piston seals from rocking in the groove. 125" and . 250" and larger. Learn more about dovetail o-ring groove design from Marco Rubber. 750 Ø to 1. An HSS cutter that corresponds to the O-ring with groove specification. Purpose – This paper aims to investigate the suitability of additive manufacturing to produce O-ring seals. Check the diameter, wall angle, corner radius and O-ring standard specifications. 051". Our O‑ring range includes metric and inch sizes to a range of international, national and industry standards, manufactured in a variety of general and high. To create an O-ring groove, click the O-Ring Grooves tab. DOVETAIL O-RING GROOVE DESIGN. Neck diameter is measured to the theoretical sharp corner. Fluorosilicone O-Rings FVMQ. (the grooves (2 per part) went around a large part and if you laid the path flat it was something like 150" long. Made of solid carbide, they are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish on hard material. If you’re printing FDM, I would use a soft sheet gasket clamped between flat flange surfaces instead of an o-ring, you’re more likely to get a good seal on the rough printed. From in-house mixing and tooling op-O-Ring Basics . Free delivery no minimum order. 66° Dovetail Cutters For O-Ring Grooves. D. 부품번호. 70 - Double End Split Blanks. The method used to produce the finish is important. 52:. Once you find the exact metric o-ring you need, you can easily order online from the world's largest o-ring inventory network. Insertable Dovetail Face Grooving Tools; GROOVE 'N TURN. D. These o-ring groove design guides offer default dimensional guidance for basic o-ring groove. Carbide Solid Cutter with Chamfer for O-Ring Groove CC-OEC3 3-Flute (Z20) Seal ring grooves are critical features on many oil and gas components, and require close tolerances and a high-quality surface finish. Bottom Rad. • Holds spiral in place. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent. Dovetail grooves are used to hold the O-ring in place during installation or maintenance. Justin . O-Ring X-Section: 0. WEAR-Lok Seals. P. Metric Features: O-Ring Dovetail Cutters Solid micrograin carbide; btrueblood (Mechanical) 13 Jun 11 13:35. 1-23) 2. 139 inch (3. One area of caution with a dovetail or a half dovetail is the naturally high ratio of O-ring volume to gland volume. Learn More > Contact. Available in ½", 5/8", ¾" and 1" diameters, the toolholders have a 1. • Easy to use • PDF output • Saving of your designs Parker O-Ring Vacuum Sealing Guide is a comprehensive pdf document that provides technical information and best practices for designing and selecting o-ring seals for vacuum applications. Side walls of machined parts should be vertical. They don't want to see any milling marks. 005". FKM Viton® O-Rings Material. We're proud to offer the world's largest inventory of readily-available and highly customized sealing solutions. An undercut or dovetail groove has proven beneficial in many applications to keep the o-ring in place. Static Male and Female O-ring Seal Design . In this application, O-ring squeeze is primarily axial in direction (valve operation exerts force on top and bottom seal surfaces). . It's also why dovetail grooves are popular. Check the diameter, wall angle, corner radius and O-ring standard specifications. An initial squeeze of the O-ring in the dovetail groove is essential to ensure that the seal functions correctly. Want to know more about installation of specific groove types? Parker has produced easy to follow videos showing how to install O-rings in dovetail grooves, face seals, and male and female radial seals. As important as the o’ring seal itself is the groove that the o’ring seats into. Manufactured by Kaiser Tool Co. 000-. Boss Seals. Before choosing a profile, you have to. Review the general o-ring groove design considerations before moving onto the specific o-ring gland design type. O-Ring Size Charts O-ring, x-ring and square ring size charts. Slot Depth. 205" and larger. , Japanese JIS, British BS, or Common Metric sizing for o-rings, these o-ring size charts will help you locate the right o-ring size. Alternate solutions for creating retention in vertically oriented face seal grooves are: • Dovetail or Half Dovetail. Carbide Dovetail End Mills for O-Rings Create dovetail grooves that allow O-rings to flex without falling out of place. Of Flutes. Create dovetail grooves that allow O-rings to flex without falling out of place. An O-ring. 70 - Long Length Single End Split Blanks. Using an appropriate tool entry method, specifically understanding when drop hole allowance is (and is not) needed, is important to keep common dovetail mishaps from occurring. The O-ring must have room to expand laterally in the groove due to axial compression. Calls out a 16 finish. An undercut or “dovetail” groove has proven effective in many applications to keep the O-ring in place. The properties of the cross-section of the groove are determined by the opening width b; the depth h; the base angle a; the inner fillet radius r1; and the outer fillet radius r2. The calculator takes all relevant parameters into account like: O-Ring squeeze.