Author Topic: Source of coil springs, rack and pinion anyone tried it?  (Read 194 times)

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Just been surfing YouTube and found this



Has anyone made a rack out of one of these gears, we come across so many broken ones that just get replaced, it could be a source of bits???
« Last Edit: 30 Mar 22, 08:07 am by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

Share on Facebook Share on Twitter


David F-R

  • Forum user
  • Posts: 171
  • Location: South Yorkshire

Badges: (View All)
Re: Sorce of coil springs, rack and pinion anyone tried it?
« Reply #1 on: 30 Mar 22, 08:10 am »
How ingenious, a ready made rack and pinion. Good find Jim.

£30 new from Screwfix so they will be cheaper somewhere.
I'm not quite as green as I'm cabbage sounding.

David F-R

  • Forum user
  • Posts: 171
  • Location: South Yorkshire

Badges: (View All)
Re: Sorce of coil springs, rack and pinion anyone tried it?
« Reply #2 on: 30 Mar 22, 08:35 am »
£30 new from Screwfix so they will be cheaper somewhere.

There are loads on ebay from£13 new. Might just get one to play with.
I'm not quite as green as I'm cabbage sounding.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #3 on: 30 Mar 22, 08:42 am »
Just got a dead one from work, I will spanner it to bits this weekend and see what the travel is
I think I may still get a piman arm on the first kart for simplicity unless this is a no brainer
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #4 on: 30 Mar 22, 07:43 pm »
OK.
Just spannered a closer to bits. The one I have moves about 40mm lock to lock in approximately 240 degrees of pinion rotation The spring that came out of it looks like 142 uncompressed, 30 OD and a 4mm wire coil
Not sure 40mm of travel is sufficient ???
... You can lead a horse to water, but a pencil must be lead.

David F-R

  • Forum user
  • Posts: 171
  • Location: South Yorkshire

Badges: (View All)
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #5 on: 30 Mar 22, 08:03 pm »
I'm inclined to agree Jim. I think 100mm would be nearer the mark.
Good for you giving it a try though.
I have looked at various racks and pinions for sale with a view to assembling a simple box, but for now I'm sticking with the standard simple swinging arm system.
I'm not quite as green as I'm cabbage sounding.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #6 on: 30 Mar 22, 08:15 pm »
I think the attachment arm has promise on this one as it  has a serrated circle of interlocking teeth at about 10 degree intervals for adjustment and a natural pitman arm from the closer lever. I might be able to use bits of it yet. The other option I to drill holes further up the arm from the king pin to increase the effect of the travel of the rack
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #7 on: 30 Mar 22, 10:02 pm »
Ok, doing some maths, I would have to site the attachment point of the track rod end 47 mm from the centre of the king pin to achieve an average of 25 degrees of steering either side of centre lock to lock on the 40mm travel of the rack and pinion gear in the door closer. This would be accomplished with about 240 degrees of steering wheel turn... How far out am I?
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #8 on: 01 Apr 22, 10:35 am »
Stripped the scrap "Geze 2000" German opener to see its guts. See pictures

It is a very solid bit of engineering with next to no lash, The pinion is on needle bearings both sides, the pinion has 41mm available free movement and the rack cylinder looks like it has plenty good metal either end to attach arms somehow.

I am NOT going to use this as a steering rack on this Kart, I am going down the Pitman arm route after a couple of conversations and some reading in fora. The spring is available if anyone needs one, I will post UK.
The lever arm was what I started looking at when I was looking for a ready made Pitman arm and may be used as the splined end might give me a bit of adjustment to align the steering wheel if I mess up.

If anyone is interested, I have one of the site guys on the lookout for different dead ones when we replace them and I might look at the comparative rack lengths from different brands. To achieve clearance with this short a throw on the rack would have proved difficult at the steering arm end.

If anyone does go down this route, I would be interested to hear about the results.
« Last Edit: 02 Apr 22, 06:55 am by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

  • Forum user
  • Posts: 628
  • Location: Cumbria

Badges: (View All)
CKGB Committee CKGB Member
Re: Source of coil springs, rack and pinion anyone tried it?
« Reply #9 on: 08 May 22, 02:21 pm »
... To follow on if anyone has any interest and for the sake of experimentation. I got a couple more dead closers from the site lads and spannered them to bits.
First up was a cheap Ebay Chinese closer. it had had a hard life by the look of the oil. the bearings were not of any note and the mechanism for the rack threw 41mm in about 2400 of turn. It could be adapted to a rack with a little ingenuity and a length of threaded bar. The rack part is on the outside of the cylinder, no lash was felt in the mechanism.

Second up was a Dorma ts73v
The oil was clean and the bearings were the needle type like the Geze.
Again this threw 43mm in 2500 total but not all of it is available with the end cap on, a little light fettling would free up the movement. Again adaptable to a rack. The rack was on the inside of the cylinder like the Geze one. No lash was present in the mechanism.

Both of these like the Geze before would require placing the track rod end nearer the king pin on a Gemini arm, and as I have said before, I am not looking for a rack on the BSA (I have a Pitman arm now) but who knows where I will go on the next one.

I also got 2 springs from the Chinese one and a one spring arrangement from the Dorma.
« Last Edit: 08 May 22, 02:25 pm by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.