Question for 'Limey' on 'Grub Screw'
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 38
  1. #1
    Join Date
    Jan 2008
    Location
    Utah
    Posts
    195
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Default Question for 'Limey' on 'Grub Screw'

    I can't find the correct user name or the thread where this topic was mentioned.

    The attached photo shows what looks to me to be pretty close to Limey's description of a grub screw, but I wanted to check since I never heard the term before.

    The setscrews are standard cup point design. The setscrew in the collar at the left was loosened for disassembly so the collar could be moved. the screw point normally seats in the spotted hole to the lower right on the shaft. Does that fit the definition of a 'grub screw'?

    There was a coupling sleeve on the keyed end of the shaft where it is slightly stained. One screw bit into the square key in the usual manner and the other engaged its point into the adjacent spotted hole. The entire assembly was quite secure and vibration resistant.

    Thanks in advance for clarification
    Dennis
    Attached Thumbnails Attached Thumbnails p5110100.jpg  

  2. #2
    Join Date
    Oct 2003
    Country
    UNITED STATES
    State/Province
    Idaho
    Posts
    2,880
    Post Thanks / Like
    Likes (Given)
    601
    Likes (Received)
    378

    Default

    Grub screw = set screw.

  3. #3
    Join Date
    Mar 2002
    Location
    Scotland
    Posts
    4,216
    Post Thanks / Like
    Likes (Given)
    1019
    Likes (Received)
    474

    Default

    Grub screw = set screw.

    Not over here it doesn`t.A grub screw is a headless screw which is threaded full length and will screw right through a tapped hole.Dennis`s pic shows them.
    A set screw is a bolt that is threaded right up to the head.
    Mark.

  4. #4
    Join Date
    Jan 2008
    Location
    Utah
    Posts
    195
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Default

    Ok, here is what it sounds like to me:

    American <-> British
    set screw <-> grub screw (headless, any style, full length thread)
    cap screw <-> set screw (hex head, socket head, etc. full length thread)
    bolt <-> bolt (as above but partial thread)

  5. #5
    Join Date
    Feb 2005
    Location
    TYNE AND WEAR, ENGLAND
    Posts
    2,517
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    15

    Default Grub Screw

    A grub is the larvae of an insect which burrows into something- and disappears.
    A grub screw is one which does exactly that!

    A woodpecker is--- no, I'd better not!

    A bark is -well, talk that one amongst yourselves!

    Cheers

    Norm- which is the mean-------and you can supply the rest-- and at my age, I need it

  6. #6
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    25,886
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    5545

    Default

    Norm's got it - except larvae = more than one, larva = singular critter.



    Jim

  7. #7
    Join Date
    Feb 2006
    Location
    SW PA
    Posts
    5,909
    Post Thanks / Like
    Likes (Given)
    1266
    Likes (Received)
    729

    Default

    A grub screw is one that you would drill a tap drill into the juncture of a coupling to a shaft, tap it, and, in effect, key the shaft. This is lengthwise to the shaft.

    I can't believe the Limeys here are ignorant of that, though I don't think they invented the term. Maybe they are young Limeys.

    Cheers,

    George

  8. #8
    Join Date
    Jun 2004
    Location
    Melbourne Australia
    Posts
    5,454
    Post Thanks / Like

    Default

    This is lengthwise to the shaft.


    Don’t you mean a Scotch Key? Whilst it might use Grub screws as part of the assembly, the method is known as Scotch keying.

    From the legend that Scot’s were frugal with money, and wouldn’t pay to have a key way machined.

    I can't believe the Limeys here are ignorant of that

    Have you been taking your grumpy pills again?

    Phil.

  9. #9
    Join Date
    Mar 2002
    Location
    Scotland
    Posts
    4,216
    Post Thanks / Like
    Likes (Given)
    1019
    Likes (Received)
    474

    Default

    Yes George,a grub screw can be used for keying a shaft,we also use it that way for keying bushes into bores when we bush something,also used as Dennis`s pic shows.But it is still a headless screw.
    Nice to be suggested that I am young as I started my apprenticeship in the early sixties.

    Mark.

  10. #10
    Join Date
    Mar 2005
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    5,323
    Post Thanks / Like
    Likes (Given)
    1640
    Likes (Received)
    1555

    Default

    Interesting. Looks like dpasek has got it straight. In my experience, the setscrews, or grub screws for you limeys, when used to secure a bushing or form a sort of key, were always called Dutchmans. Funny how we all use similar but different terms to describe things in the vernacular in the different english speaking countries. On a side note, I used to work with a Brit whose nickname was Limey. He was a master at darts.

  11. #11
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    25,886
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    5545

    Default

    Ditto on the "dutchman" designation.

    That's what I've always heard those called. I think
    it's a variation of "german" or deutch.

    Jim

  12. #12
    Join Date
    Aug 2006
    Location
    Brisbane, Queensland
    Posts
    1,288
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3

    Default

    Quote Originally Posted by eKretz View Post
    He was a master at darts.
    Darts are called arrows sometimes.

    A set screw is a bolt threaded all the way to its hex head. A grub screw has no head and is threaded for its whole length. Before having a socket end they were mostly slotted for a screwdriver.

  13. #13
    Join Date
    Jul 2005
    Location
    Newcastle, Australia
    Posts
    613
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    166

    Default Bolt or Screw?

    So when does a bolt become a screw or vice versa?

    To say "a 2mm bolt" would be thought odd!

    It seems to me that 6mm/1/4" is about the point of transition from "screw" to "bolt" but I wonder why.

    I did my apprenticeship (nearly 50 years ago) in Australia with a firm that did heavy engineering; we used the term setbolt to describe a bolt threaded all-the-way. That meaning is not given in on-line dictionaries today although my Googling showed that the fully-threaded bolt that retains a vehicle crankshaft pulley is called a setbolt in automotive circles.

    A similar device smaller than about 6 or 8mm would have been a setscrew.

    And a grubscrew (setting aside the old joke) was & is a headless screw as Damien & others have described.

  14. #14
    Join Date
    Apr 2003
    Location
    Topeka KS
    Posts
    1,221
    Post Thanks / Like
    Likes (Given)
    105
    Likes (Received)
    71

    Default

    So when does a bolt become a screw or vice versa?
    An explanation I read somewhere is that a bolt (hex heads) takes a nut and a screw (SHCS-socket head cap screw) goes in a tapped hole but that's not common usage. Around here, just about everything with a head is called a bolt and any headless screw is a set screw. The ones with a square head are square head set screws.

    When I hear Dutchman, I think of a pressed in plug to allow the fixing of a machining error. Not sure where I got that though.

  15. #15
    Join Date
    Sep 2004
    Location
    south SF Bay area, California
    Posts
    2,092
    Post Thanks / Like
    Likes (Given)
    170
    Likes (Received)
    698

    Default

    Let's not forget that what U.S. 'Murkin English first called a "setscrew" had a square head. In use, those setscrews showed a proclivity to snag just about anything that came close to them, which lead to the development of what was, at first, termed a "safety" setscrew that didn't protrude from the hub of the pulley / wheel / sheave or lathe dog.

    British Commonwealth "grub screw" = obsolescent US "safety setscrew" = current US "headless setscrew"

  16. #16
    Join Date
    Feb 2006
    Location
    SW PA
    Posts
    5,909
    Post Thanks / Like
    Likes (Given)
    1266
    Likes (Received)
    729

    Default

    Phil,

    I religiously take my "grumpy pills". Scots have no comparison to a US executive when it comes to cutting costs. A Scot will cut costs till it becomes dangerous. A US exec will far surpass that. They will weigh the relative cost of lawsuit against financial benefit using the cheapest method they can. They can tie up a case in the courts till they have made so much that an adverse finding in court will seem like a drop in the bucket.

    Mark,

    I thought that what we were speaking of WERE what are called "setscrews", ie, straight threaded, headless, socketed, screws. Before modern materials, "setscrews" were "headed bolts", whether hex or square. I don't know when the Allen was invented.

    Planner,

    Why would you change nomenclature at a given dimension. A 2 mm capscrew would be the same as a 30 mm capscrew. It does have to be bolted and nutted to become a BOLT. A bolt, actually, was first defined as a plain shanked piece of some material that was used to halt movement. And then, 'bolts" are rolls of cloth and the like. Messy, don't you think?
    We use "capscrew' and should be happy with that.

    We have Allen head capscrews and we have hex head capscrews. OR, you can call anything over 1/4 a BOLT, anything under a screw.

    Do as youwish.

    Cheers,
    George

  17. #17
    Join Date
    Jan 2006
    Location
    BC Canada
    Posts
    439
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    9

    Default

    Here is a definition of the difference between bolts and screws.
    Bolt versus screw definition. The correct definition of bolt and screw is as follows. Bolts are headed fasteners having external threads that meet an exacting, uniform bolt thread specification (such as M, MJ, UN, UNR, and UNJ) such that they can accept a nontapered nut. Screws are headed, externally-threaded fasteners that do not meet the above definition of bolts.
    This definition was lifted from this site. http://euler9.tripod.com/bolt-database/22.html

  18. #18
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    18,690
    Post Thanks / Like
    Likes (Given)
    2136
    Likes (Received)
    3323

    Default

    AFAIK a bolt has a nut, and a screw does not........

    Cap screws being an example........ may be made to bolt specs...... add a nut and it's a bolt....

    GRUB-screws are those little headless ones that when you drop one, make you GRUB around on the floor looking for the little ^%$#@.

    probably originally got the name for the way they GRUB into the shaft, burring it up so it will NOT come out of the pulley without a hammer,........

  19. #19
    Join Date
    Feb 2006
    Location
    SW PA
    Posts
    5,909
    Post Thanks / Like
    Likes (Given)
    1266
    Likes (Received)
    729

    Default

    Robin,

    Thanks for the link. Where in that chart do you see the difference you refer to?

    Looks to me as though "bolts" and "screws" have the same metallurgical requirements.
    Thread and dimension have different "point" references, how much difference, I don't know, I looked at your link, am not going so far as to analyze your quibble.

    In some cases, especially for you who do work for pay, you have to get the proper fasteners. Of course you would spec that when you order.

    People here who do work for pay have asked about thread classes. They are worried about the work they are producing, whether it is meeting requirement.

    Another definition of a "screw" is that it is fully threaded. A "bolt" is required, I think, to be threaded to 2 1/4 or 2 1/2 times the diameter.

    Cheers,

    George

  20. #20
    Join Date
    Dec 2007
    Location
    Hunter valley nsw - Australia
    Posts
    69
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1

    Default

    This is an interesting thread (and the pun was not intentional)
    When I started my apprenticeship in 1974, here in Oz, at the location I was at, the definition of bolt or screw was pretty easy. If you used a screwdriver to turn it it was a screw and if you used a spanner it was a bolt, Allen keys were classed as a spanner. Its interesting to see how the terminolgy for different things changes as we become more and more "globalised" and we have access to better and faster long distance communications.

    bollie7

  21. Likes Casady Machine liked this post

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •