Best pen-style erasers according to redditors

I mean, if you are doing that much erasing, just get a separate stick eraser. You don't lose your pencil, so I don't see why losing the eraser would be a problem. You can get a lot of good eraser for not that much money, and you don't seem to mind paying for new stuff every few weeks anyway.

I bought them off Amazon, these are where I bought them from.

Uni Kuru Toga Advance 0.5mm Black

and the

Tombrow MONO Zero Pen-Style Eraser (this came with two sizes. a 2.5x5mm one and 2.3mm one).

E: JetPens has the pencil for cheaper, not sure if they sell the eraser as I was checking the weight of the pencil.

Nice collection! I have a few more items for you to consider adding, should you be so inclined:

• Uni Kuru Toga Pipe Slide: Plastic variant of the same line but with a retractable tip. Although I prefer the feel of the Roulette (which you already have in silver), I carry the Pipe Slide in my shirt pocket every day because it won't poke holes like the Roulette does. For those unfamiliar with the Kuru Toga line of mechanical pencils, they automatically rotate the lead every time you press it to the paper, avoiding flat spots and keeping it sharp on all sides. Note that this occurs each time you press down, not as you keep pressing. Thus, drawing a line rotates one notch (because you only set the tip to paper once), whereas writing letters, dots, etc. rotates multiple notches as you continue to repeatedly press the tip to the paper for each character.
  
• General's mechanical eraser: finer tip than most mechanical erasers, and nice pen-style grip. Refills are also available but I've found they're often cheaper locally. (Amazon sells 3-pack refills for ~$4 but my local college art store sells them for half that.)
  
• Tombow Mono mechanical erasers: Extremely fine erasers for detail, more than even General's, for uses such as erasing small lines while drawing. You can order sets of both shapes (round and rectangular) or just one, and they're available in silver or black.

Cheap and good: Staedtler 925: 3-pack of 0.3mm, 0.5mm, and 0.7mm for $20. Individually sold at art/stationary stores for $5-$10 each.

The metal version by Pentel: GraphGear 500: 4-pack of 0.3mm, 0.5mm, 0.7mm and 0.9mm for $20. Individually sold at stores for $10-$20 each. They're okay, and people like the metal look, but I prefer the Staedtler.

The good stuff: rOtring. rOtring 600: $23. rOtring 800: $50.

I haven't tried the rOtring pencils myself; I've heard they're good, but I've been pretty happy with the Staedtlers. Although they're the cheapest I mentioned, they're also very comfortable and reliable. I've never had one fail (I have had Pentel pencils fail, including but not limited to the ones I linked), and I've been using them for years.

Make sure you get a decent mechanical eraser to go with them. A Tombow MONO zero in an amazing eraser for the details, and a Sanford Paper Mate Tuff Stuff is good for everything else. Buy an extra pack of the refills and you're good for a while. Note: Do not buy the Sanford eraser for more than $5. The price on Amazon right now is ridiculous. The Tombow is a little more pricy; $5-$10 is fair for it.

Strain gages are always going to measure normal strain in the direction of the grid due to a change in length in the direction of the grid. This is why the grid is very long in the measurement direction and short in the transverse direction (to minimize transverse sensitivity). When it comes to shear strain, think about it like this: shear strain is simply an angle change in the material - and the resistance change in the gage grid due to an angular change is going to be tiny since it doesn't elongate the grid much at all. It's so tiny, that most strain gages rarely list shear sensitivity (as opposed to transverse sensitivity) since it is incredibly low.

Where things get a little confusing is that they make grid patterns specifically for measuring "shear strain" - like the ones you linked to. These use a pair of gages (you'll need two measurement directions to figure out the shear!) with the elements oriented 45 degrees on the backing and 90 degrees to each other. This also assumes you know that you only want to measure shear and that you know the direction of maximum shear. So now you have to go back to your Mohr's circle and remember that in a pure shear stress state (like say, in an ideal torsional spring), the maximum principle (normal) strains are at 45 degrees to that shear strain.

So for your specific application, assuming the gages were aligned correctly with the shear direction, you are measuring the principle strains (or very close to them) in a pure shear application. Hopefully the two measurements are close to equal and opposite of each other? If they are not, check the alignment of the gages with respect to the spring. If they are close to equal and opposite, take the average of the two asbsolute values and you will get the tensor shear strain. Keep in mind the difference between tensor shear strain and "regular" engineering shear strain. Scroll down here for a decent run-down on the two:
http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/strain.cfm

I'd go look up a spring in a mechanics of materials book. They should have an example that breaks out the max principle strains from the actual loading of the spring. That should give you a way to prove to yourself what you have measured, assuming you know the load on the spring and all the spring dimensions/properties.

To visualize the deformation in pure shear a bit better, look at the diagram under Pure Shear Strains here: http://continuummechanics.org/smallstrain.html

The blue diamond is how the material will actually deform in pure shear. Think of it like holding the bottom left corner and top right corner and pulling them apart. The red block elongates (positive normal strain) in the direction of +45 degrees and shrinks (negative normal strain) in the -45 degree direction. You are placing your gages to measure this elongation and shrinking along these directions. The key is you know ahead of time that you have a pure shear (or close to it) environment and what this direction will be. If you did not know this direction, you would need a three element rosette which can be used to derive the entire state of strain at a point.

Once you have a handle on all of that, look up info on transverse sensitivity corrections to eek out that last few percent of error....

Another fun way to visualize this is to take one of those long eraser pencils like this: https://www.amazon.com/Pentel-Eraser-Retractable-Assorted-ZE21BP3-K6/dp/B010CEFH2E/ref=sr_1_11?ie=UTF8&qid=1478658061&sr=1-11&keywords=eraser

Draw a small square in the middle of the eraser. Now twist each end of the eraser to put it in torsion and watch how your square deforms!

I got mine from a japanese stationery store, but you can get it online too. Here it is on amazon with refills. It comes in handy a lot for fine detail erasing.

I used one of these for 3 years of my undergraduate physics degree, and then for all the classes in my phd time. Still have it, love it. If I need to write something in graphite, this is my go to tool.

Also, if you need to do precision erasing, pair it with one of these:(https://www.amazon.com/Tombow-Pen-Style-Eraser-Refill-Refills/dp/B00ZZ4PJRA/ref=sr_1_7?keywords=mechanical+eraser&qid=1571968831&sr=8-7).

The mechanical eraser isn't as high of quality as the mechanical pencil, but for precise erasing like I sometimes needed to do in equations, its the best I've ever seen. Obviously use a regular eraser for bulk erasing (or just toss the paper lol).

Faber-Castell is an excellent brand, no worries there. So they like pencils? Moleskine and Paperblanks sell nice sketchbooks. Fixative is a good idea. And erasers, like kneading erasers and pen erasers are useful.

Here ya go! Uni E-Knock Eraser - White Body https://www.amazon.com/dp/B002U0OKNQ/ref=cm_sw_r_cp_apa_eeSQAb9CY82B7

If you want to clean up those sharpie lines, get like a white eraser and use that to rub off the excess.

Usually the eraser is an afterthought- a tiny little thing under a cap.

I prefer using separate erasers anyway (e.g. one of these), so I just use the little tiny eraser when I forget my usual eraser.

Now you're talking one of the biggest problems I always had as well! Drawing white hairs/details was easily one of my biggest roadblocks. I tried white pens and such, and personally didn't like it.

I 100% recommend a "Tuff Stuff" eraser stick. The stick itself is no different than any other mechanical eraser, but the eraser itself is a godsend. It is extremely durable and tough. I cut the end of it with scissors to create a sharp edge, and then I use it to eraser white lines into my graphite. It's best used on light graphite to get your white guidelines set, and then you darken the area around after drawing your white lines. Regular erasers sticks are generally no good because they're too soft. They just can't get the sharp, crisp erase lines like the tuff stuff ones do.

Unfortunately they aren't easy to find any more, and can be quite expensive now.

https://www.amazon.ca/Eraser-Refillable-Rubberized-PAP64801-Papermate/dp/B00N6G3Z4I/ref=sr_1_cc_4?s=aps&ie=UTF8&qid=1469119898&sr=1-4-catcorr&keywords=tuff+stuff+eraser

The stick itself I've seen range anywhere from $10-$100.. It's pretty ridiculous, you should definitely look around for awhile before you buy. I bought mine long ago for $8. The refills are what is really important though. The best deal I've found is here for 24 sticks: https://www.amazon.ca/Paper-Eraser-Holder-Refill-64818/dp/B00006IFAZ/ref=sr_1_1?s=office&ie=UTF8&qid=1469120190&sr=1-1&keywords=tuff+stuff+eraser

I couldn't recommend it enough, but again, it's personal preference =].

I'm exclusively a 0.5mm lead user.

My preference is a 2B or a 3B for smoothness, and I use Pentel Ain Stein lead. (Got a multi pack from 2B-4B for $12) It tends to write slightly darker than a standard lead, however, it does get used up much faster. This for me is not an issue since the difference at least in my hands is so much smoother.

There are many notebooks to choose from, maybe check out /r/notebooks but be warned your wallet might hate you. I like the Semi B5 size since it is without margins and if you write small it approximates the similar writing area for my personal use since I never used the margins in the 5 star notebook types. The lines in the maruman are very light and easy on the eyes. The paper is very heavyweight and thick. I typically find it hard to see through the pages so you can write on both sides without seeing lines pass through. The covers are a heavy duty plastic material and great for long term use.

I got these notebooks for archival purposes. I use them to write down engineering formulas and notes on designs -- things that I need to constantly reference and have handy. I paid about $8 each notebook with tax and shipping. Highly recommend them!

Here are the particular items I got so you can take a look:

https://www.amazon.com/dp/B017BDDZ7I - Kuru Toga

https://www.amazon.com/gp/product/B01HODH9QI - Leads

https://www.amazon.com/gp/product/B00OPQA7SK - Eraser (Don't buy the multi pack the erasers suck, but the holder is awesome. I took a Pentel Hi-Polymer eraser, and cut it up with a razor blade to shove on the sticks this thing comes with. Best eraser you can use! I also have the Pentel clic but it's not as good as the blocks since it's a harder polymer so it smears and doesn't erase perfectly.)

https://www.amazon.com/gp/product/B00SWVXZ5G - Maruman Notebooks in Semi-B5

Also, shop around. Prices vary greatly for these items. Amazon may not be the cheapest, and sometimes Jetpens can be a huge ripoff so shop around before you buy!

My Holy Trinity: Mitsubishi Pencil 9000 HB Two Point Sharpener Mono Eraser

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They have the Mitsubishi Pencil 9850 HB, which has an eraser on it, but I would suggest using a pencil without an eraser since erasing can be a time waster. I found it really motivating that what I write is final, but I also prefer a separate eraser anyways and without an eraser on the pencil I don't risk smudging the lead with an inferior pencil eraser. (although the Mitsubishi pencils are alright)

That is why I carried one of these back in my engineering/physics days.

Now that I am in computer science, I don't bother.

Here are some ideas!

http://amzn.to/2F0X2EA ( royal purple flowers)

http://amzn.to/2CnOxWF ( royal purple socks)

http://amzn.to/2ozHq49 ( royal purple tie)

http://amzn.to/2EY94yK (royal purple shoelaces)

http://amzn.to/2Fz1Xhg (royal purple baseball cap)

http://amzn.to/2EXSZJw (royal purple glass water bottle)

http://amzn.to/2CpBxzX ( purple sunglasses)

http://amzn.to/2sWrZZf ( lamp with royal purple shade)

http://amzn.to/2GMJtsX ( royal purple notebook)

http://amzn.to/2BR9XdA ( purple pens)

http://amzn.to/2ouFTNH (royal purple inflatable solar powered light)

http://amzn.to/2F8labT ( another lamp)

My favorite color is coral!

If anyone is curious about refill erasers like I was, the Sanford Tuff Stuff eraser sticks are the right diameter, and you can just use a razor to cut them to a desired length.