Questions_and_Answers.docx

Questions and Answers:

+206 Pan Note 4, machining of finish thickness by others? [Yes, Print Updated] +211 Ring Would a welded construction be acceptable? [Yes, Print Updated.] +307 Lower No call out given for the 12 holes with boxed dimensions [Print Updated] +308 Upper Need depth of .625 grooves [Print Updated] +401 Comet Holes L1 – L10, Shi 1 has a depth, sht 2 calls for thru [Print Updated] +403 Rd Qtr There is a section AA but no arrows showing where it is taken[Print Updated] +411 Templet Missing I.D and B.C diameters[Print Updated]

1. Where 1/2”, 1”, 1-1/2”, and other “stock sizes” are given, due to commercial material manufacturing tolerances the flatness and parallelism tolerances would need to be relaxed (+/- ,010 or .015?). Also applies to width of +413 clamp. [Thickness/flatness have been relaxed, or “stock” note removed from some relevant parts, Prints Updated]

2. The 63ra finish callout seems unnecessary on dimensions with tolerances of +/-.005 and +/-.010. Unless necessary for fit-up to another part, 125ra should be adequate. [Agreed, Surface tolerance has been relaxed, see comment below. Prints Updated]

3. Engraving method SAE AS478 method 15B2 is laser engraving. No character height is stated. Also, in some cases, Vibro peen or metal stamp (lightly applied) in accordance with MIL-STD-130 might be more appropriate. Can these be made options? [Scratch engraving, rotary engraving, and vibro/dot peen (effectively, but not technically an engraving process) are all acceptable; engraving notes changed to be a bit more generic, including min. character height of ½”. Engraving depth is up to the vendor’s discretion – so long as its legible. We still really want to avoid stamping these parts, as it would almost always be on a mating surface. “Light” stamping risks leaving poorly defined character edges, might have to be followed up by sanding/stoning/scraping , and possibly filling with layout dye or paint for contrast. Not really worth the trouble vs Laser engraving in these cases in our opinion. Prints updated]

4. ”Per drawings 130902MRA402 and 130902MRA404, the material specified is ASTM A276. This specification covers bar stock. There is neither bar stock or rolled plate available in 304 material large enough to make the required part size (15 x 24 x 26.5"). Either a forging per ASTM A473 or a casting per ASTM A703 would be required. Cost-wise, the casting would be better. Please advise.” [An ASTM A473 spec (forged stock) would be closest to the original design intent, but no reason not to allow machining from a cast blank (ASTM A703). Prints Updated]