What does "Jobber Length" mean?
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Outlawmws
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They are shorter than the std drill sets so are less likely to get broke off; good for hand drills and holes in thin material or shallow holes.
slipjointed
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Jobber refers to a general purpose length bit. From what I've been told it refers to the fact that they can handle most jobs.
You also have long length, and short, or mechanic's/machinist's length bits. Another bit type is Aircraft, which gives you the length of Jobbers, but with only the tip ground to a spiral. This allows you to have rigidity but still have reach, but with a reduced drilling depth, which is perfect for work in aircraft fastening structural members to the skin, etc.
The bit length allows you to drill through thicker workpieces, but it also severly reduces the rigidity of the bit.
The Jobbers length has been settled on as the best compromise between length and rigidity.
For most hand drilling, I prefer short length if possible, as they don't flex as much and therefore are much less likely to break.
Short drills are also far superior for precision work clamped to a drill press table or on a milling machine, as you can drill accurate holes without having to centerpunch or drill the hole first.
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diesel research
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slipjointed
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^^^ this
Jobber length bits are standard drill length. Mechanic or Maintenance length are the ones that are slightly shorter.
diesel research
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There is an even shorter one called "screw machine" and a long air craft version that might be up to 12" or more in length and maybe only 1/4" diameter.
slipjointed
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The really short machine drills are used in machine shops, you can chuck them up in precision chucks and just go to town drilling without having to worry about pre-drilling to prevent the bit from walking on you.
You can't use normal bits in precision applications (>.001" tolerance) because the length will make them walk every time, no matter how good the drill, and how ridgid the fixture is.
Something that everyone should have, but I rarely see people carrying, is an automatic center punch. It takes fabrication work to a whole new level as far as quality. I can't even count the amount of times I've had to struggle because someone was trying to just start a hole with a bit and managed to walk it all over the place.
The aircraft drills are often similar to jobber's length, but they only have spiral near the very end, the rest is just unground shank, as mentioned above they are used for aircraft because you usually have to get into tight spots, but are normally drilling through thin structural members and sheet metal, so you don't need very much spiral to exhaust the chips.
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american lockpicker
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I think I have some of those.
diesel research
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mark40sw
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Farmall450
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I love it when I google a question & garage journal comes up.
joel63
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I love it when I google a question & garage journal comes up.
You can count on getting an intelligent answer.
You can count on getting an intelligent answer.
Plus a whole lot of ******** and some just downright scary or dangerously wrong answers.
lg
no neat sigline
FJ 432
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neonlazer
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I love it when I google a question & garage journal comes up.
Same..took way too long to ask the question, though.
There are different lengths of jobber drill bits. http://blog.carbideprocessors.com/uncategorized/the-difference-between-jobber-lengths/
Jeeper
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Drill lengths are typically based on a multiple of diameter, so a 1/4" jobber bit will always be approximately half the length of a 1/2" jobber.
For jobber bits the length is typically 10 or so diameters.
Outlawmws
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Mgnu
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And definitely an argument.
Yes, Snap-on is overpriced and for suckers who like debt.
Harbor Freight 44" tool box will rule them all.
Did we cover all the bases yet?
AndrewDouglasBird
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Short drills, or "machinist" drills as some have called them, are known as stub drills. They are used for precisely drilling a hole as they are more rigid and less likely to wander.
Silver and deming drills are drills with a reduced shank, generally above 1/2" diameter (with a 1/2" shank). These drills got their name from a company, much like how circular saws are often referred to as skill saws.
Silver and deming drills are drills with a reduced shank, generally above 1/2" diameter (with a 1/2" shank). These drills got their name from a company, much like how circular saws are often referred to as skill saws.
Yes, Snap-on is overpriced and for suckers who like debt.
Harbor Freight 44" tool box will rule them all.
Did we cover all the bases yet?
Where was it made?
APEowner
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The ones that have been broke and resharpened are bad mechanic length
383 240z
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Yes they are, I've run screw machines, and have never used that style of drill! When I set up the machine I use a drill only a bit longer than the main tool cam. Keith
4 FN 27
ALLIANCE MEMBER
Lots of good reading here:
http://www.vikingdrill.com/viking-Product-Catalog.php
My buddies FIL runs the show there. Went for a tour...cool stuff and great drill bits.
http://www.vikingdrill.com/viking-Product-Catalog.php
My buddies FIL runs the show there. Went for a tour...cool stuff and great drill bits.