exams

Your exams have been graded and are available for pickup in 1131ggb starting tomorrow at 8am. The score statistics and solution will be posted by tomorrow evening. Please don't be alarmed by the low mean score, as this has no bearing on the letter grade equivalent. The approximate equivalent of a score at the mean is B/B+.

wiring tutorial

The control system document has been updated to include a step-by-step guide for wiring to motors, using the wires and banana plugs that are required for connecting to the ME250 control box. These components are available in the crib.

http://bit.ly/3n4FzO

lab section meetings and 1131 hours

Please note the following modifications to our lab section schedule:

- Lab sections will meet normally this Monday (tomorrow)

- Up to 12 people from other sections can work in 1131ggb at this time, with priority on the signup sheet; however, the GSI's priority will be on working with the teams meeting at that time

- Lab sections will NOT be held this Wednesday ...32 spots are open all day Wednesday

- Lab sections will be held next Monday, for MS9 - the shop will be closed to all other sections at these times

- Lab sections will be held next Wednesday, for machine inspection and seeding - the shop will be closed to all other sections at these times

We know that the shop will be very busy this week -we will open 1131ggb for limited additional hours if needed; however, we first need to see that most of the normal (8a-7p) hours have been reserved by advance signup. Of course, any open space in the shop is first-come, first-serve, but if it is too crowded (unsafe) we will need to enforce the roster.

1131 signup this week

Welcome back from the break. It's only 11 days until the me250 contest! ... so, we expect the shop will be crowded this week. Please secure time (note the time limits per team) at the link below; if we are full (>32 people in 1131), the GSIs will enforce the signup roster.

http://bit.ly/5iXVUH

safety

As some of you know, one of our shop assistants injured his hand while drilling a part last week. This was entirely preventable if the part had been held properly, and this unfortunate incident is a reminder to take utmost care when working in the shop.

Many of the things we're using, both in the ME250 shop and the ME machine shop, are very dangerous -taking a shortcut to save time, or taking your eyes/mind off the situation for even a split second can cause harm.

Please keep safety mind first whenever/wherever you are working --look out for yourself and for others, and don't hesitate to ask the staff if you are unsure of what to do.

recent scores

the grade spreadsheet has been updated with scores through MS8, excluding the exam. (the exam will be returned this week)

http://bit.ly/NKQG0

thicker angle Al

We've purchased thicker (1/4" x 1 x 1) right angle aluminum stock, which will be better for use as pillow blocks. If you have already used the 1/8" thickness as pillow blocks, we don't expect you to replace it; however, you are welcome to do so, and if you are building new parts, consider using this stock. This is available (1' per team) upon request from the crib.

John

graded HW

All graded HW - including HW5 (motors) - is in the box on the table at the front of 1131ggb.

second planetary gearbox

If your team is planning to use a second planetary kit and has not obtained one from the crib already, please ask your GSI during the MCM review tomorrow. We would like to use the remaining motors as replacements for the burnouts.

If your team still needs a replacement motor (beyond the #2 normally available), please tell your GSI this as well.

MS8 - assembly drawings

You will NOT be required to show assembly drawings for MS8. The complete solid model, and individual part drawings are sufficient (same as for MS6).

control system availability/clarifications

A few details about the RC control system:

- as described in the google doc http://bit.ly/3n4FzO, your machine must hold the control box and battery pack

- these items are NOT included in the size constraints stated in the rules

- the control box and battery must be securely mounted to your machine just before you compete, and must be removed from your machine when you are finished; we will replace the battery and give the system to the team on deck. We recommend using velcro to mate the box to your machine.

- we will have control system(s) available for check-out from the crib starting next Monday, November 30. The GSIs will be responsible for charging the batteries.

- wiring, banana plugs, etc. for connecting your motors to the control box will also be provided; further details to follow before Monday.

MS8 grading

Please refer to the 'MS7 to end' .pdf on ctools for details and point allocations for the MCM (MS8). We expect you to demonstrate your MCM as completely as possible; specifically, if it contains a motor you should hook it to the DC power supply and demonstrate the motion capability. The 'all engineering' will be graded similarly to MS6. You will not be expected/required to use the RC control system until the full machine demo later.

You will have less than 10 minutes for the full review with your GSI (including the engineering for the rest of your machine). So, be ready to describe your MCM, and explain how it met expectations and how it may require improvement/modification in the coming weeks.

"lecture" 20

Lecture slides on mounting, joining, and interfaces have been posted on ctools (lecture 20). You may be particularly interested in the design suggestions for coupling shafts to motors, and mounting/fits of bearings, bushings, and wheels - these include recommended drill sizes, and a design for robustly constraining wheels to shafts (including non-kit components you can get in the crib now)

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Today's Agenda:

-Coupling shafts to motors

-Mounting and fits: design suggestions

- Shaft dimensions and tolerances

- Bushings to pillow blocks

- Bearings to pillow blocks

- Wheels to shafts

-Joining and assembly methods: from high‐temp to low‐temp

- Welding and brazing

- Soldering

- Adhesives

- Threaded fasteners

- Snap‐fits and e‐clips

MS8 attendance

I expect that some folks will be leaving early for the Thanksgiving break - as a result, we will not require all of your team members to be present for lab section Wednesday (MS8). However, if one or more of your team members will be absent, please notify your GSI before 9.30AM Wednesday. The team members in attendance will be expected to demonstrate all the MS8 requirements.

fasteners available in 1131 GGB

Machine Screws
Thread Size	Length	Head Style	Drive Style	Material
#4-40	1/4"	Pan	Philips	Zinc-Plated Steel
	3/8"	Pan	Philips	Zinc-Plated Steel
	1/2"	Pan	Philips	Zinc-Plated Steel
#6-32	1/4"	Pan	Philips	Zinc-Plated Steel
	3/8"	Pan	Philips	Zinc-Plated Steel
	1/2"	Pan	Philips	Zinc-Plated Steel
	3/4"	Pan	Philips	Zinc-Plated Steel
#8-32	3/8"	Pan	Philips	Zinc-Plated Steel
	1/2"	Pan	Philips	Zinc-Plated Steel
	3/4"	Pan	Philips	Zinc-Plated Steel
#10-24	1/2"	Pan	Philips	Zinc-Plated Steel
	1"	Pan	Philips	Zinc-Plated Steel
1/4"-20	1/2"	Hex	Hex	Zinc-Plated Steel
	1"	Hex	Hex	Zinc-Plated Steel
	3/8"	Flat	Philips	Zinc-Plated Steel
1/2"-13	3"	Hex	Hex	Zinc-Plated Steel
Socket Cap Screws
Thread Size	Length	Head Style	Drive Style	Material
1/4"-20	1/2"	Standard	Hex socket	Black-Oxide Alloy Steel
	3/4"	Standard	Hex socket	Black-Oxide Alloy Steel
	1"	Standard	Hex socket	Black-Oxide Alloy Steel

Nuts
Thread Size	Type	Material
#4-40	Hex	Zinc-Plated Steel
#6-32	Hex	Zinc-Plated Steel
#8-32	Hex	Zinc-Plated Steel
#10-24	Hex	Zinc-Plated Steel
1/4"-20	Hex	Zinc-Plated Steel
1/2"-13	Hex	Zinc-Plated Steel
Washers
Screw Size	Shape	Material
#4	Round	Zinc-Plated Steel
#6	Round	Zinc-Plated Steel
#8	Round	Zinc-Plated Steel
#10	Round	Zinc-Plated Steel
1/4"	Round	Zinc-Plated Steel