Author Topic: Enlarging Holes in Thick Plate  (Read 16527 times)

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #25 on: May 17, 2014, 01:16:06 PM »
Then made up a stepped alignment peg and a jig. I didn't have any 1/2" plate to hand so welded a couple of bits of 6mm plate together for the jig
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #26 on: May 17, 2014, 01:18:15 PM »
Pop the alignment peg in the hole. Clamp the jig round it and off we go  :ddb:
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #27 on: May 17, 2014, 01:20:34 PM »
End result: a pair of 22mm holes enlarged to 1" - and the barstock that I'll use for pins actually fits  :lol:
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #28 on: May 17, 2014, 01:34:30 PM »
So far so good. However next job is to weld up an outrigger parallel to the existing plate, as the pins extend past the existing one through a 'top link' (*)  swivel eye and without additional support would be be susceptible to bending.

I sliced up a length of heavy 3" x 4" x 8mm angle to form the out riggers - need to bore a 1" hole in the right place then weld them in place. Job for Monday as tomorrow is full with family duties.


(* Top Link is basically a huge turn buckle - a pair of spherically aligning  1" bore eyes mounted on 1 1/8" UNC left hand and right hand threads, with a threaded tube between them allowing adjustment of eye to eye spacing. Conventionally used on a tractor 'three point linkage' as the upper support which needs adjustment to set the angle of the attached implement. In this case being used as bracing supporting the weight of the flail and thus avoiding using the hydraulic raising bars.)

Andrew Mawson
East Sussex

Offline RotarySMP

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Re: Enlarging Holes in Thick Plate
« Reply #29 on: May 18, 2014, 03:46:18 PM »
Thanks for posting the pictures. Just out of interest, what final size did that 25mm hole saw end up cutting?

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #30 on: May 18, 2014, 04:23:30 PM »
I haven't actually measured it but they are a tightish push fit on nominal 1" bar. In fact I may have to use an adjustable reamer to ease them out a bit, as you don't want tight pins when trying to get things in alignment and assembled.

I'll weld on the extra web, in which I will have pre-drilled a hole, then decide how to ease them out a bit. A flap wheel may be sufficient if things don't move too much with the welding, otherwise I'l pass a 26mm  reamer through them.
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #31 on: May 21, 2014, 09:28:25 AM »
The Postman brought a one metre length of 1" EN24T bar this morning, so it rapidly got converted into three pins and a spacer:
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #32 on: May 21, 2014, 09:30:07 AM »
The bigger pins go through those pesky holes, and also through an outrigger that I've welded on to give a bit more outer support to stop the pin bending too much:
« Last Edit: May 21, 2014, 11:37:38 AM by awemawson »
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #33 on: May 21, 2014, 09:33:22 AM »
This pair of brackets take both the lower lift arms of the tractor, and a triangulated set up so the not inconsiderable weight is taken by the tractors 'top link bracket'. This way the set up can be adjusted to be rigid and not differentially twist the hydraulic lifting shaft.

Here is a mock up of the triangulation, where the 1" bar at the front of the picture mimics the top link bracket on the tractor
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #34 on: May 21, 2014, 09:37:04 AM »
Now the astute amongst you will have noticed that the eyes on that bar need to come much closer together, but the ball socket in the eye doesn't give enough 'crank'

Cranked eyes must be available as I have one on a top link that in it's original purpose should have been straight anyway !, but so far I've not managed to obtain another one !
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #35 on: May 21, 2014, 09:46:50 AM »
The threads on these are 1 1/8" UNC. Now I've found ones with 3/4" UNC but not 1 1/8". Usually these sorts of things are available in the Sparex catalogue, but not this actual one  :(

The link I have with a crank is made in India by the unfortunately named Swastik company who have an emblem remarkably like the one young Mr Hitler used to use. Never the less I've not been able to track down any bent eyes !

http://www.indiamart.com/swastik-engineering-products/


I suppose if I have to I can bend one having heated it with oxy-acetylene, but not sure if they are heat treated after forging  :scratch:
« Last Edit: May 21, 2014, 10:45:52 AM by awemawson »
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Enlarging Holes in Thick Plate
« Reply #36 on: May 21, 2014, 10:41:08 AM »
Can you scratch the crooked version at the bend with a file, Andrew?
I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Enlarging Holes in Thick Plate
« Reply #37 on: May 21, 2014, 10:57:15 AM »
Since I may have to reproduce a hardened valve rotator cap, not knowing the degree of hardness they were originally tempered to, I did a search and came up with this list from Wikipedia:


    Faint-yellow 176 C (349 F) engravers, razors, scrapers
    Light-straw 205 C (401 F) rock drills, reamers, metal-cutting saws
    Dark-straw 226 C (439 F) scribers, planer blades
    Brown 260 C (500 F) taps, dies, drill bits, hammers, cold chisels
    Purple 282 C (540 F) surgical tools, punches, stone carving tools
    Dark blue 310 C (590 F) screwdrivers, wrenches
    Light blue 337 C (639 F) springs, wood-cutting saws
    Grey-blue 371 C (700 F) and higher structural steel

It seems to me that maybe I can use this info to get an approximate hardness measure of an existing cap, by scratching it with some of the above to see where the hardness falls. Kind of like doing a hardness scratch test to identify minerals.

Handy that the translation to a tempering color can be got by using this list as well.
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #38 on: May 21, 2014, 11:12:47 AM »
Steve,

Both the 'cranked' eye and the straight ones are file-able. A quick bit of trig shows that I need about 13.5 degrees on both ends. Now the ball swivels look to have been made to accommodate 10 degrees, and the cranked version measures at about 15 degrees - ( crude measurements with it clamped in a vice, and eyeing a protractor to be parallel with the bench ! )

Useful list that you reproduce there - I can see it being handy to interpret hardness from things lying to hand. A bit like a Moh's scale of hardness where things are listed in order of their ability to scratch others. Perhaps we can call it ' Steve scale of Tool Hardnesses '  :clap:

I have a feeling that the oxy- acetylene torch is coming out to play soon  :lol:
Andrew Mawson
East Sussex

Offline RussellT

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Re: Enlarging Holes in Thick Plate
« Reply #39 on: May 21, 2014, 11:48:19 AM »
I must have misunderstood something here.  Surely the closer the eyes are together the less resistance to torque there is, which I thought was the point of the modification.

Russell
Common sense is unfortunately not as common as its name suggests.

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #40 on: May 21, 2014, 12:54:05 PM »
Russell,

The assembly is forming a rigid pyramid - but what is not showing in the picture are the lifting arms that pivot on lugs on the tractors axle and the outer ends go onto the pins though the enlarged holes.

Normally these arms are connected to links dropping down from levers on a shaft that runs parallel to the axle, but at a higher level. the shaft being rotated by a beefy hydraulic cylinder and thus raising the arms.

Now if the hedging flail rocks from side to side, more load is placed on one lifting arm than the other, and this over torques the shaft, and indeed has broken one in the past  :(

I am doing away (while the flail is mounted) with the links that drop down from the levers, and replacing the lifting hydraulic force with this rigid pyramid of adjustable 'top links' so I can pre-set the height off the ground, but when tightened up there will be no slop at all.

On the rear of the tractor (all tractors) there is a mounting point for the 'top link' that is specially designed to be a strong attachment point, comprising a pair of projecting lugs with a pin through them. The actual 'top link' goes between these lugs and my 'support top links' will go on the same pin, but on the outer side of the lugs. To avoid having a wide (and thus easily bent) pin, the 'support top links need to be snug up against the lugs. I am planning to weld up a bridge piece to pick up the ends of the pin and take reinforcement from a second pair of lugs this particular tractor is furnished with.

A bit complicated - I hope I explained that lucidly  :scratch:
Andrew Mawson
East Sussex

Offline micktoon

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Re: Enlarging Holes in Thick Plate
« Reply #41 on: May 21, 2014, 05:34:21 PM »
Hi Andrew look like the job turned out well , excuse the pun  :lol:. I used to own a 1956 Grey Fergie TEF20 4 cylinder diesel and remember messing about trying to get impliments to fit that , flail mower etc, The little tractor still did everything it would have done when it was new 50 years after it was built  :thumbup:

 Cheers Mick.

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #42 on: June 08, 2014, 09:30:23 AM »
This project has been dragging on as I have failed to source 'bent eyes' for the 'top links' so today I decided to take things in hand and ask the oxy-acetylene torch to give me a hand!

You'll recall that standard ends are straight but I needed cranked ones to get the correct angle
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #43 on: June 08, 2014, 09:31:18 AM »
So with the help of the gas axe we ended up with this:

Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #44 on: June 08, 2014, 09:35:55 AM »
Currently they are cooling - when just warm they'll get a light spray of zinc rich paint to replace what was burnt off.

I had a bit of inspiration the other day - went to an 80 th birthday celebration of a friend, which involved staying over night in the motorhome on a local farm. Tucked in a barn obviously not used for decades was 'the real thing' A hedge flail mounted on a tractor using the proper adaptor plate. First time I've been able to get 'up close and personal' with this item. Well not too close, it was deeply buried in nettles.

However I got a few photos of the adaptor and the way the lower pins were supposed to be.
« Last Edit: June 08, 2014, 10:00:09 AM by awemawson »
Andrew Mawson
East Sussex

Offline awemawson

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Re: Enlarging Holes in Thick Plate
« Reply #45 on: June 08, 2014, 09:37:16 AM »
So the next job is to draw up a plate like the triangular ones in the photo and glue it all together with a bit of 6013
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Enlarging Holes in Thick Plate
« Reply #46 on: June 08, 2014, 10:43:40 AM »
Must be the season for tractor work!  :beer:
I love it when a Plan B comes together!
Steve
www.sredmond.com