Author Topic: How to make Gib Headed Keys,the most easiest way?  (Read 1157 times)

Offline Xldevil

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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

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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

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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

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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.

Online b.lindsey

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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

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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

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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.


Online b.lindsey

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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

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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

Online b.lindsey

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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

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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

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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

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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
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SB 10K lathe, Benchmaster mill. And stuff.

Offline 10KPete

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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

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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

Online Dan Rowe

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #15 on: January 04, 2018, 04:14:38 PM »

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.
In the US tapers are usually given in inches per foot not as a ratio. 1:96 is 1/8" per foot.

The common taper for US taper pins is 1/4" per foot or 1:48. The metric taper pin is 1:50.

The taper attachment on my South Bend lathe has degrees on one end and inches per foot on the other. I suspect it is the same for a Boxford lathe also.

Dan
ShaylocoDan

Offline Johno

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #16 on: January 04, 2018, 04:56:10 PM »
Dan,

UK Imperial tapper pins are also 1/48 with the metric ones being 1/50. So it would appear whilst US/UK, & Can/Aus/Nz/etc. tapper pins are interchangeable, gib-head (& plain tapper keys) keys are not. It would interesting to understand to what extent other common components may not be that interchangeable as first assumed?
How many times has some one used metric tapper pin reamer, that was at hand, just to find out that the US/UK tapper pin always proved to be a poor fit. Or vis-versa ?

ian

Online Dan Rowe

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #17 on: January 04, 2018, 06:02:56 PM »
Ian,
BS 46 might have the taper as 1:100 now but I just looked in "Machine Drawing and Design" by William Ripper the Dean of Applied Science University of Sheffield 1914. Page 51 lists the taper of a key from 1 in 64 to 1 in 96.

It looks like you should check when working on historic equipment.

The taper pin issue was always a problem on the ships I was on. Some of the equipment used metric pins and anything from the US had imperial pins and it is not easy by looking to know which was which.

Dan
ShaylocoDan

Offline Johno

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #18 on: January 04, 2018, 07:19:45 PM »
Dan,

BS 46 an very early 1950's standard, so it must be assumed before that it was down to the "Works Engineer" to devise the standard such items were built to. You can imagine the rivalry between the different manufacturers when claiming that "their system" was better than others.

So, you are right of course to be wary when working on very old equipment and trying to determine what standards they may have be built to. I would suggest that there was no standard given that it was not until the 1840's that Sir Joseph Whitworth developed the first standard for screw threads and went on to develop the first screw cutting lathe in order to make standard nuts & bolts. Up until that time screwed components were made by individuals and no two would match another persons. Standards for other components would also not of have existed.

I recall as an apprentice I had the opportunity to do a little work on the a full size replica of a steam locomotive. It was a replica of "Locomotion No 1" built in 1825 to mark it's 150 year anniversary. Locomotion No 1 was built to haul the Worlds first Steam Public Railway : The Stockton- Darlington in 1825. On the original, the bearings were fastened to the con-rods by a system of yolks, keeper plates & wedges, no two assemblies were the same & certainly not interchangeable. When replicating the parts we used tools and equipment that simply did not exist 150 years ago & ours just looked to "engineered" to convey the period. So, for the first time as apprentices, we were asked to make rough looking parts!

Offline Bobsmodels

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #19 on: January 04, 2018, 07:38:12 PM »
Hi

I posted this awhile back and it may look like overkill, but once you spend about a half hour to make the master for which ever system you use it is easy to get repeated results.  Easy to set up the for a
new sleeve and to make keys.  You do not have to set up angles every time. 

Bob

Offline Xldevil

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Re: How to make Gib Headed Keys,the most easiest way?
« Reply #20 on: January 05, 2018, 05:38:04 AM »
Talking overkill,this is a very nice tool.

<a href="http://www.youtube.com/watch?v=pwcw5lCskyE" target="_blank">http://www.youtube.com/watch?v=pwcw5lCskyE</a>

http://www.repco-tech.co.uk/keyway-cutting-tool/


Made an inquiry,but I guess the price is far beyond my budget.
« Last Edit: January 05, 2018, 05:41:08 AM by Xldevil »