What is the depth of a spot face?
Spotface – The cutting of a shallow counterbore, usually about . 0625 deep (depth symbol is omitted). A spotface provides an accurate bearing surface for the underside of a bolt head.
What do you mean by spot facing?
The most common application of spotfacing (spot facing) is facing the area around a bolt hole where the bolt’s head will sit, which is often done by cutting a shallow counterbore, just deep enough “to clean up”—that is, only enough material is removed to get down past any irregularity and thus make the surface flat.
What is one difference between a counterbore and a spotface?
is that counterbore is a cylindrical recess, typically machined around a hole to admit a screw so that it sits flush with a surface while spotface is a shallow circular or cylindrical recess, machined on (for example) a cast part to offer a flat face against which to seat a fastener; a shallow counterbore.
Which type of milling machine is used for spot facing?
Seco spot facing mills are cutters for milling spot faces of blind and countersunk holes. Key benefits include smooth cutting, reduced spindle bearing wear via a highly balanced tool and high security through a center-lock clamping system, all engineered in an economical solution.
How do you dimension a Spotface?
How to dimension a spotface. A spotface is dimensioned by specifying its diameter and depth. At times the amount of remaining material may be specified instead of the depth.
What is counterbore countersink?
A counterbore (symbol: ⌴) is a cylindrical flat-bottomed hole that enlarges another coaxial hole, or the tool used to create that feature. Whereas a counterbore is a flat-bottomed enlargement of a smaller coaxial hole, a countersink is a conical enlargement of such.
How do you call a spot on your face?
The symbol used to callout a spotface is the counterbore symbol with the letters SF in the middle. This is per the engineering drawing standard ASME Y14. 5. At times, a blueprint may indicate a spotface feature simply through the use of a counterbore symbol.
What is the difference between Counterboring and countersinking?
Countersinking creates a conical hole matching the angled shape on the underside of a flat-head screw. Counterboring creates a flat-bottom hole, which allows the head of a screw or bolt with a flat underside to rest solidly in the counterbore, often atop a washer.
How do you dimension a countersink hole?
Write the dimensions of the countersink, giving first the diameter of the drill hole, then the angle of the countersink, followed by the diameter symbol and the diameter of the larger hole. This dimension can be given either with a diameter symbol first, or with the word DRILL after the first diameter.
What is the nominal diameter of the spot-faced surface?
For example, in Boeing Design Manual BDM-1327 section 3.5, the nominal diameter of the spot-faced surface is the same as the nominal size of the cutter, and is equal to the flat seat diameter plus twice the fillet radius. This is in contrast to the ASME Y14.5-2009 definition of a spotface, which is equal to the flat seat diameter.
Does a spotface have to have a depth?
A spotface does not always require a depth. If it is on an uneven surface, the depth defaults to the minimum required to achieve a full diameter. Here’s an update, now that I have the references at hand. the drawing callout per Y14.5 is the same as a counterbore callout, except that the depth may or may not be specified.
What is the spotface diameter of a fastener?
The spotface diameter depends on using a washer (what size) or not. Depends on the type and size of the fastener head. If the fastener uses internal wrenching, then no wrench clearance. If the fastener uss external wrenching, then spotface diameter depends on required wrench clearance.
What is spotspot facing?
Spot facing is a mechanical drilling, or milling, process. After the initial hole is drilled, a larger well, or recess, is drilled into the material. The head of the screw or nail fits into this well. This allows the nail or screw to sit flush with the surface of the item that is drilled.