Large Binocular Telescope Project

Questions & Answers

concerning the RFP for the

Enclosure Rotation Bogies and Drives

July 14, 1997

Question 1. (received 17 June 1997, regarding Autocad drawings)
Please send the font "Sans Serif" file from AutoCAD 12 or 13. This file is not existing in our AutoCAD Version. Your AutoCAD drawings request the font file: SAS_____.PFB

Answer 1. This file is now available at
(Hint: Press the shift key before you click on this link.)

Question 2. (received 18 June 1997)
Drawing 341a009 shows the drives attaching along the axis of the wheel, while other drawings such as 341a000 show the drives coming in from above. Which do we intend?

Answer 2. Drawing 341a009, as indicated on the label and the technical description, is only a "typical" drawing to illustrate how the reaction arm for this type of gear box can be designed, but does not represent our particular gear and bogy. Drawing 341a000 shows exactly the gear and motor assembly we are going to adopt for the LBT bogies.

We underline also that the gear / motor units are not part of the bogies RFP, but are parts that shall be supplied by the LBTPO for the integration.

Questions 3, 4, and 5 will have a more detailed reply in a report being prepared by ADS in a few days. Brief answers are provided below.

Question 3. (received 19 June 1997)
What are your ultimate tensile and yield strengths of material needed to handle the load design? We have found no specifications of materials listed. i.e.: (Plates for fabrication, Rounds for axles, Wheels- should they be rim toughened or deep hardened?)

Answer 3. Materials:

Question 4. (received 19 June 1997)
There are no weld symbols on the furnished drawings. Based on your load design could you please furnish any data on weld sizes?

Answer 4. We will shortly provide a sketch of the welding details of the main weldments. For the main connections between the web and the top and the bottom flanges we request a single or double bevel preparation for full penetration welding in the center most stressed areas and a good penetration proportional to the thickness of the plates for the full length --- like in all these types of structures.

The sketch is available as a new revision of drawing 341a000c.dwg.

Question 5. (received 19 June 1997)
Are there any NDT (non-destructive testing) requirements?

Answer 5. For the materials, the quality certificates of the steelwork are sufficient. For welds, ultrasound or penetrating dye tests should be used. We expect the proposal of the quality control from the Supplier. Remember that these structures are requested all stress relieved before the machining.

Question 6. (received 25 June 1997)
What are 89/392/CEE rules?

Answer 6. These rules are the European safety and quality rules that every European manufacturer must comply with. They include also the operational and maintenance manuals described in the Statement of Work. Non-European manufacturers need not follow these rules for LBT, provided that the meet the other requirements of the Statement of Work.

Question 7. (received June 27, 1997)
What is the request for proposal number as indicated in Attachment C (Proposal Format) sections 1.1, 2.2, 3.1 and 4.1?

Answer 7. There is no proposal number only a proposal name which in this case is "Enclosure Rotation Bogies and Drives".

Question 8. (received July 2, 1997)
What is the Engineering reponsibility intended? Obviously detail drawings must be made, but as materials are generally not specified and certain details are unclear, it is difficult to bid without more detailed information. Operational parameters are given, but without more geometric information on the entire structure, loads cannot be analyzed. Can the design shown be presumed to be acceptable?

Answer 8. The engineering responsibility of the Supplier is for the shop drawings and the details of the mechanisms. Successful execution of these details requires good experience in the design and construction of these types of mechanisms. The LBTPO and the design engineers of the enclosure and bogies take responsibility for the overall loads and the interaction with the structure of the Rotating Enclosure and the Circular Rail. These loads were summarized in the Technical Report on Rotation Bogies and Drives (301a002). An additional report is being prepared which summarizes the dimensioning criteria for the various sections and axes of the bogies.

Question 9. (received July 2, 1997)
What is the interpretation of call outs such as "C40 UNI 7478 Hardened"?

Answer 9. The equivalent American steel to "C40 UNI 7478" is "AISI 1040". For UNI standards see: ENTE NAZIONALE ITALIANO DI UNIFICAZIONE the Italian National Standards Body.

Question 10. (received July 2, 1997, regarding drawing 341a003)
What is a US equivalent for "Bronze G-SnCu 12 UNI 7013"?

Answer 10. The bronze nut is of the most common material you can find on the market. This is a mechanism that has only gravity to balance.

Question 11. (received July 2, 1997)
We know that the question has been asked, but can you supply us with ASTM equivalents for Fe 360 UNI 10025 and Fe 430B UNI 10025?

Answer 11. (see also Answer 3 above. The equivalents have proven difficult to sort out. We are still working on this problem.)

Question 12. (received July 2, 1997)
It is noted that there is a weight discrepancy.
4 wheel Ass'y = 22200 Kg x 2 = 44400 Kg
6 wheel Ass'y = 32900 Kg x 2 = 65800 Kg
Total = 110200 Kg, yet the listed supply weight is 97000 Kg. Comment?

Answer 12. It is only the difference represented by the n.8 driving units (GEARS AND MOTORS) that shall be supplied by the LBTPO, so not part of the supply of the Bogies Manufacturer.

Question 13. (received July 2, 1997)
Alignment tolerances for wheel axles are not specified. What accuracy is required for convergence?

Answer 13. Our goal is having the axis of all the wheels of one bogie included in a circle of 1 mm diameter positioned in the center of the rail at the level of the top of the rail. What we are expecting to find in the proposal is the tolerance the Manufacturer can guarantee and the method proposed to achieve this tolerance.

A new drawing has been created to show how an alignment telescope might be mounted on the wheel axis. This drawing is 341a011.

Question 14. (received July 2, 1997, regarding drawing 341a003)

Answer 14. The small motor driving the stow pin is 0,37 kW -- 4 poles, European size 71B, flanged to a worm gear reducer size 63.

Type UM1451152 Rubber Packing is a standard rubber seal that you can buy for a shaft to protect the inside guided length from dirt.

Question 15. (received July 14, 1997, regarding proposal deadline)
Could the proposal deadline be extended by one week? We are having problems working around vacations and quotes for long-lead items.

Answer 15. Yes, we will agree to extend the proposal deadline for the proposals regarding Enclosure Rotation Bogies and Drives by one week. The new deadline will be July 30, 1997.