Author Topic: A Bit Over Engineered (Read 17638 times)

doubleboost · « **on:** August 21, 2011, 02:39:18 PM »

Hi
A friend of mine asked me if i could build him a spike harrow to tow behind a quad
His wife has a horse she rides on a arena made from what looks like bark chippings
It has become compacted and needs braking up
This is what i came up with
!0 metres of 40 mill heavy wall box section and a bit of welding

John

DaveH · « **Reply #1 on:** August 21, 2011, 03:03:26 PM »

Hi John,

Looks great nicely made, looks strong.

I use to work on a farm many years ago. There was a special hitch that would disengage if the plough or whatever decided to dig in. Otherwise the tractor would tip up and throw you off the back right under the plough.

Just thought I would mention it.

DaveH

sbwhart · « **Reply #2 on:** August 21, 2011, 03:06:00 PM »

Nice bit of fabricating and welding John, a strong looking Jobby.

Stew

John Hill · « **Reply #3 on:** August 21, 2011, 05:50:54 PM »

Quote from: DaveH on August 21, 2011, 03:03:26 PM

Hi John,

Looks great nicely made, looks strong.

I use to work on a farm many years ago. There was a special hitch that would disengage if the plough or whatever decided to dig in. Otherwise the tractor would tip up and throw you off the back right under the plough.

Just thought I would mention it.

DaveH

...or just make sure the hitch point is below the level of the rear axle.

Stilldrillin · « **Reply #4 on:** August 22, 2011, 03:53:15 AM »

A nice bit of fabbing there John!

Hope it works as good as it looks.....

David D

PekkaNF · « **Reply #5 on:** August 22, 2011, 05:22:17 AM »

I don't see all the workking angles so my concern might be ungounded.

If ground is all treebark or such that might work. On rake? I have seen those spikes are springy things, like some coils on the upper end to give in when you run into obstacle. Those strong steel rods might rip off or bend.

Also, as stated before, I would consider some sort of slipjoint or such on the hitch to allow some slack after a snatch.

PekkaNF

doubleboost · « **Reply #6 on:** August 22, 2011, 05:18:21 PM »

The tow hitch is below the axle centre height so the quad will be poulled down
There is a 6 inch layer of bark on top of a membrane the spikes will only go in 4 inches
We will find out how it works at the weekend
Thanks for your concerns
Regards
John

doubleboost · « **Reply #7 on:** August 24, 2011, 10:57:17 AM »

It workes fine

Hooked it up to the quad set the height great result first time

Click the last picture

All in all a very satisfying project
(i even made a few quid to spend on tooling)
John

Stilldrillin · « **Reply #8 on:** August 24, 2011, 12:13:45 PM »

That's a crackin' piece of kit John!

I knew it would work, first time out......

David D

sbwhart · « **Reply #9 on:** August 24, 2011, 12:18:03 PM »

Fine bit of work

You'll be getting a few orders for those when the word gets round.

Stew

DaveH · « **Reply #10 on:** August 24, 2011, 01:32:39 PM »

John,

Can't get any better than that

DaveH

raynerd · « **Reply #11 on:** August 24, 2011, 02:00:27 PM »

Nice one John, looks great and seems to work a treat!

Chris

John Hill · « **Reply #12 on:** September 01, 2011, 03:23:49 AM »

It sure looks the part John!

I would say it is plenty strong enough too but if the ground is compacted to any depth you might find it lacking somewhat in which case I suggest about half as many tines and slope them forwards somewhat.

I was a farm boy many years ago and of course we had various types of harrows and in certain conditions it was necessary to weight the harrows or they just bounced along on the surface, but I think a quad bike would not have the traction to handle that.

About the worst thing I can imagine happening if you hit something solid (like what

?) would one or two of those tines bend, in which case you will get a piece of pipe and bend it back!

Great project.

DMIOM · « **Reply #13 on:** September 01, 2011, 03:56:06 AM »

Looks a good bit of kit John and exactly right for the job as specified - i.e. appropriately engineered, not over-engineered.

Quote from: John Hill on September 01, 2011, 03:23:49 AM

.......I was a farm boy many years ago and of course we had various types of harrows .....

me too!

Quote

About the worst thing I can imagine happening if you hit something solid (like what ?) would one or two of those tines bend, in which case you will get a piece of pipe and bend it back!....

I know its not a grubber, but I too was thinking along similar lines and how the tines or points on some of our harrows had a threaded top and fastened up though holes in the cross-bars (if these ones were of hollow box I'd have made the holes bigger and welded in suitable sleeves); it also then gave scope to adjust the number of tines in play, and/or replace them with spring tines or similar.

Anyway, don't let us farm boys lead you astray into scope creep (well, not until you start on the next one!

Dave

John Hill · « **Reply #14 on:** October 03, 2011, 04:00:21 AM »

Dave, we had harrows with the threaded tines too. If I recall correctly the nuts would never unscrew so a cold chisel was brought to bear and a new tine put in, in fact I think they were only taken out when they were being replaced and it was always a suprise just how much longer the new ones were, or maybe we just had stoney, sandy ground!

MadModder

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