Saturday, March 23, 2024

I Have a Ream

 Everybody knows that drills put holes in things.  Most people assume they are perfect holes - but some people who need accuracy know that is not the case.  So, what kinds of holes, and what to expect?  My brief, inexpertise scale from worst to best :

  • Hand drill - if you need a quick hole and don't care about vertical, size, or anything else, do this.  Even with "drill guide" blocks, you're likely to not get it vertical.  If you are going to thread this hole for a bolt, please avoid this one.  I will throw in cheap drill presses here - though with some work, they can be a little more acceptable toward the next category.
  • Drill press - these are good for getting rid of the above "vertical" orientation issues of a hand drill.  For this category, I'm throwing in drill presses, magnetic drill braces, and I'll even throw in the old Craftsman "Port-Align" attachments to the above hand drills.  They offer better consistency in your vertical alignment.
  • Drill in a lathe - sometimes you can throw the part into a lathe.  These give you MUCH better control over axis alignment, plus the holes become much more - dare I say it - ROUND!  Now, you thought the previous holes were round.  Sure, they were, kind of.  But now we're getting into a much better category and much more accurate concentricity.
  • Boring bars in lathes (or boring heads in mills).  These give you not just a concentric and round hole - these actually let you control the diameters of the said holes.  One drawback of these is the machining marks in the holes, as these are typically single-point-cutter tools that have radii on the cutting end, so while the holes are much more accurate, they still are on the rough side.
  • Reamers.  These are specialty tools designed to give you the best finishes possible, while giving you exactly the dimension you wanted.  The holes are round, concentric and parallel (provided you don't let them wander off course).

Now, I've started thinking through a low-profile, small, milling vise build, and I know I'm going to need better holes than I've done.  So, a "drill" isn't going to cut it, and what I really want are "reamers".  I found a hodgepodge of reamers on eBay that might cover the sizes I need, so I bought it, and classified their sizes (not all are stamped).

So, I measured these, not with actual use, but using some metrology equipment, which means these are likely +/-0.002".  For example, the 0.373 might be a 0.374, and the 0.374 might be a 0.376.  The only way for me to tell is to use each individual reamer, but I'm too tired and fatigued to drill that many holes without good test equipment that I can chuck some of these reamers into without moving drill heads, bases, or anything the like.

For now, suffice to say I have the following sizes in hand :

  • 0.155"
  • 0.183"
  • 0.187"
  • 0.189"
  • 0.218"
  • 0.219"
  • 0.246"
  • 0.280"
  • 0.308" (2x)
  • 0.309" 
  • 0.310"
  • 0.311" (5/16") (2x)
  • 0.354"
  • 0.373"
  • 0.374"
  • 0.382"
  • 0.498"
  • 0.499" (2x)
  • 0.500"
  • 0.515"
  • 0.749"
  • 0.751"
  • Morse Taper #2 (this was a bit of a surprise!)

Next up, trying to feel a bit better.  This could be a longer road to travel before I can get back to projects, but I've gotten this far.  If I can do so, perhaps I can start doing the mill vise.

No comments:

Post a Comment