Author Topic: How to make Gib Headed Keys,the most easiest way?  (Read 3339 times)

Offline Xldevil

  • Full Member
  • ****
  • Posts: 58
How to make Gib Headed Keys,the most easiest way?
« on: January 03, 2018, 05:14:34 AM »
Hello.
I would like to fasten the flywheel of the engine I‘m building by the use of a gib head key.
The axle is 8 mm in diameter .
How to make the key( the dummie way,please)and how deep and
how long has to be the cut in the axle and in the flywheel in relation to the key ?
Thank you for any helph.
Ralph

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6302
  • Surrey, UK
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #1 on: January 03, 2018, 07:25:05 AM »
Take a piece of rectangular key steel or gauge plate, set it up in the mill vice at the required angle 1:96 if imperial or 1:100 if metric and mill to shape.

Make the key so it is say 90% the width of the hub plus the head, keyway in flywheel goes all the way through and should be tapered to match key, length of keyway in shaft will depend a bit on the individual engine, if flywheel is up against a bearing than stop the slot just short of the bearing, if flywheel in the middle of a shaft then cut beyond the far side.. Depth of keyways can be found on the net and will vary depending on the width of your key.

This shows an easy way to set the metal to the right angle for milling shallow tapers. For 1:96 pack up one end of the rule by 1/16" over a 6" length and use like a parallel to suport the work. If doing a metric one then 2mm of packing over 200mm length will work


Offline Ian S C

  • Full Member
  • ****
  • Posts: 1025
  • Stirling Engine Maker Darfield Canterbury N Z
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #2 on: January 03, 2018, 10:44:52 AM »
I used a gib head key for the flywheel of a Stuart Turner S9, the grade of steel is unknown, it was made by cutting out with a hacksaw, and filed to shape.
Ian S C
         
« Last Edit: January 03, 2018, 10:47:56 AM by Ian S C »

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 745
  • North Wales, Great Britain.
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #3 on: January 03, 2018, 12:54:15 PM »
Hello All.

Gib head keys, the most common of fasteners used on many early stationary engines. A small, simple component but a right pain to make!

I, like Ian used to cut them from “ Gauge plate “ and either file or mill into shape. Jason has shown how to get the correct taper.

As a “ rule of thumb “ I always measured the thin end of the key and then divided by two putting half the thickness into the crankshaft key way and the other into the flywheel.

I got so tired of the tedium I bought a job lot of 200 in my production days. The money spent saved many hours!

Cheers Graham.

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13128
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #4 on: January 03, 2018, 03:53:16 PM »
Nice simple method for getting the taper Jason, will file that one away!! Thanks

Bill

Offline Xldevil

  • Full Member
  • ****
  • Posts: 58
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #5 on: January 03, 2018, 05:17:53 PM »
Thank you all for your tips.
@Jason,your method seems to be very practicable and I will definitely give it a try.
There is one thing that confuses my slightly; in the picture you posted it seems
that the key is clamped into the vice upside down
and that you mill the taper on the bottom of the key.
Shouldn‘t the taper be on top of the key and the bottom should be flat?
Another question,is only the key way in the wheels hub tapered and the part in axle
flat?
Thank you again,Ralph

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6302
  • Surrey, UK
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #6 on: January 03, 2018, 05:32:46 PM »
That was something else I was machining using the same method but as you say the key should be held with the part that goes against the shaft downwards and then you cut the taper on the top which goes against the flywheel.

Ideally the keyway in the hub should have a matching taper so if using a broach you need a bush with a tapered slot or of cutting on the lathe using the slotting method then it is easiest to pack one side of the flywheel so that it sits at the taper angle across the lathe axis.

The other thing to mention is that if you do cut your key from rectangular key steel then leave it attached to the ful length as it is easier to hold while you fine tune the fit of the key.


Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13128
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #7 on: January 03, 2018, 05:50:05 PM »
Maybe this will help too Ralph.

Bill

Offline AOG

  • Full Member
  • ****
  • Posts: 658
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #8 on: January 03, 2018, 09:45:49 PM »
Ok, I’ve got to ask. Is tapered keyways a model engineering thing?  All of the keyways I see here in the States in real world use are straight. Is there some advantages to tapered keyways for models? Straight keyways certainly are easier to broach.

Tony

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13128
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #9 on: January 04, 2018, 12:05:32 AM »
Tony, the advantage in both models and full size applications is that they can be more easily removed using that raised head by tapping them out or prying them out, making it easier to then remove the pulley, flywheel or whatever.

Bill

Offline Dave Otto

  • Full Member
  • *****
  • Posts: 3531
  • Boise, Idaho USA
    • Photo Bucket
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #10 on: January 04, 2018, 12:30:24 AM »
And when properly fitted they hold like there's no tomorrow :lolb: No set (grub) screws needed.


Dave

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6302
  • Surrey, UK
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #11 on: January 04, 2018, 07:19:58 AM »
Tony, go and look at any of the old full size stationary engines that seem to be everywhere in the US and they will all have gib head keys holding the flywheels in place and nothing else.  Straight keys are more common now to transmit the drive but use some other way to retain the actual flywheel/pully etc

Maybe you should have said you don't see them in the modern world rather than the real world ;)

Offline 10KPete

  • Full Member
  • ****
  • Posts: 1556
  • Nordland, WA, USA
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #12 on: January 04, 2018, 07:51:15 AM »
And if you use Jasons method for setting the angle when you cut the bushing for the broach AND the key itself.... little to no hand fitting would be required!  :ThumbsUp: :ThumbsUp:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline 10KPete

  • Full Member
  • ****
  • Posts: 1556
  • Nordland, WA, USA
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #13 on: January 04, 2018, 07:57:41 AM »
....... Straight keyways certainly are easier to broach.

Tony

The only trick, if the is one, to the tapered broach set-up is to remember to only push the broach down with the arbor press a little bit, then lift the ram a few thou to allow the broach move over because of the taper.

Did that make any sense? If the broach were pushed through in one fell swoop the broach would probably break. I was taught to always let up the pressure every half inch or so..

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Johno

  • Full Member
  • ****
  • Posts: 43
  • South West, UK
Re: How to make Gib Headed Keys,the most easiest way?
« Reply #14 on: January 04, 2018, 03:46:23 PM »
Hi all,
Bit confused here, when I was on the "tools" during the 70's it was understood that the Imperial standard for gib head keys in the UK was 1/100 tapper the same as metric & not 1/96 as Jasonb suggests.

BS 46 & Din 6887 standards refers.

I understand however, the in the US the standard is a 1/96 tapper, but just because other dimensions are in inches that does not make it the "the Imperial" standard. They should be referred to as compliant "Customary Units" that are very similar to Imperial but are not Imperial in the true meaning of the word. Let's remind ourselves that US gallons are different to that of Imperial gallons.

Just thought I would mention it. Either way, both 1/100 or 1/96 tapper keys will be equally effective.

Ian