M3 screws seperate

[Chrislong]

Hi Guys,
The screws holding the hinge pin blocks onto the Cat SX are prone to bendages, and I highly recommend people check these after each meeting at the minimum - after each heat if you feel the car is getting some abuse.

Until now, these screws have only been available in a large pack of screws - so you end up with many other screws to get just the ones you need. Which isn't such a bad thing at first, but eventually you'll end up with loads of other screws. :lol:

But now, Nortech have come to the rescue, and are supplying the M3 screws individually. They are as follows:

M3 x 10mm cap head
M3 x 12mm cap head
M3 x 20mm cap head

If you haven't already got spares, I recommend any Cat SX owner to carry many of each of these to ensure that when they bend (they will), the screws can be replaced straight away and the SX will continue to handle like the awesome machine that it is. :thumbsup:

http://www.nortechracing.co.uk/

Chris

[telboy]

You can never have too many screws Chris!! :p

:thumbsup:

[TEINsports]

Those are M4 if i remember correctly.....those that are screwed into the bulkheads

[ben]

Dont think soo dude

[Chrislong]

Those are M4 if i remember correctly.....those that are screwed into the bulkheads

You have a kit don't you? Have a look in the manual. :lol: They are M3 though.

[Chrislong]

You can never have too many screws Chris!! :p

:thumbsup:

Agreed!!! :thumbsup:

[TEINsports]

You have a kit don't you? Have a look in the manual. :lol: They are M3 though.

you are right, my mistake.:blush:

And yes, they are prone to bendages.

[Chrislong]

So, TEIN, the question is - will Nor-tech ship to Singapore? I reckon he will.

[dbizzle5]

I have tried several times to buy these now and when I get to the pay part it just goes to a Paypal error screen??? How do I pay!!????

[Northy]

I have tried several times to buy these now and when I get to the pay part it just goes to a Paypal error screen??? How do I pay!!????

you have pm :)

[Lee]

Selling screws is like making love to a beautiful woman :thumbsup:

[Kecky]

you mean we're being screwed :lol:

[TEINsports]

So, TEIN, the question is - will Nor-tech ship to Singapore? I reckon he will.

:lol: i never had the intention to get screws half the globe from UK. I reckon that Nortechs are quality stuff but its simply not cost effective for me....But i have no choice when it comes to the CAT's spares. :yawn:

[glypo]

I am putting high tensile M4 screws on mine, can't be bothered with these bent M3's.

[rcracer]

Bent mine today and it resulted in a broken outdrive :cry:

[Oliv996]

I am putting high tensile M4 screws on mine, can't be bothered with these bent M3's.

I think I will do the same on mine... do you have pictures of mods you've made?

[Northy]

I'd be careful guys, you may end up damaging other parts :(

G

[Oliv996]

I'd be careful guys, you may end up damaging other parts :(

G

Agree with you Northy, more damages on wishbones are predictable... :yawn:

BTW, I made the mod on the front end yesterday and I will do the same on the rear end today... Some pics very soon ;)

[Northy]

I was thinking more like putting more stress into the gearbox sides and chassis :o

G

[Oliv996]

Here is the mod consisting of replace the M3 screws of bloc pivot by M4 screws.

The front end with machined button head M4 screws:

http://img504.imageshack.us/img504/3674/dscn8663xv3.jpg

http://img504.imageshack.us/img504/500/dscn8664ho0.jpg

http://img504.imageshack.us/img504/6505/dscn8665nq5.jpg



The rear end with machined socket head M4 screws:

http://img440.imageshack.us/img440/8545/dscn8666qs7.jpg

http://img504.imageshack.us/img504/6151/dscn8667na9.jpg

http://img440.imageshack.us/img440/3407/dscn8672as2.jpg

[Chrislong]

Hi Olivier,
Now thats hardcore :thumbsup:

Fancy bagging up conversion kits prepped to be built this way? (as many of us, such as me, won't want to do this mod) Im guessing it'd need gearbox halves front and rear, all the purple blocks and the 12 screws? ;):thumbsup:

How much?

[frogger]

Nice job! I'll have a conversion kit as well if there will be one :D

[glypo]

I have M4 screws in mine also. Sorry didn't see the post asking for photos before, I will sort some out later.

Northy, it is not possible for the mod to put more stress on the transmission housing, if anything it takes away stress.

It's not exactly a hard mod to do, although I will put a step-by-step guide in my follow up review soon to be finished.

[Northy]

It must put more stress into the gearbox sides....

G

[barnyard]

The gearbox sides have enough material in them (especially the front) the pivot blocks are more of an issue when drilled out.

I even know team drivers running the car with the front end modified

[Northy]

Who? :confused:

I must admit I had thought about it.

G

[glypo]

It must put more stress into the gearbox sides....

G

How? It takes it away.

Just got in from work and I'm doing maths again already....

M3 = Nominal diameter 3 mm
M4 = Nominal diameter 4 mm

Stress = Force / Area

Therefore stress is inversely proportional to area.

Circumference = pi x d

M3 = 3.14 x 3 = 9.42 mm
M4 = 3.14 x 4 = 12.56 mm

Obviously this is a 33.3% increase in surface area, thus stress around the screw will drop by 33.3% also. So therefore the stress will be reduced on the housing with a bigger bolt.

[Oliv996]

Thanks Chris !!!!

I do not plan to produce a machined M4 and M3 screw set but if some of you want I could make an effort... I would prefer to let you drill and tap the require parts (gearbox halves, bloc pivots, spacers) 'cause it take a while and I have to do it for French guys who already ask me :D

Once I will do the job on french side, I will consider your demand Chris as my small contribution to Team Schumacher UK :D

Olivier

[Oliv996]

How? It takes it away.

Just got in from work and I'm doing maths again already....

M3 = Nominal diameter 3 mm
M4 = Nominal diameter 4 mm

Stress = Force / Area

Therefore stress is inversely proportional to area.

Circumference = pi x d

M3 = 3.14 x 3 = 9.42 mm
M4 = 3.14 x 4 = 12.56 mm

Obviously this is a 33.3% increase in surface area, thus stress around the screw will drop by 33.3% also. So therefore the stress will be reduced on the housing with a bigger bolt.

The ration between M3 and M4 is quite still the same but you must consider the core diameter of the screw: 2.5 for M3 and 3.3 for M4 ;)

[glypo]

The ration between M3 and M4 is quite still the same but you must consider the core diameter of the screw: 2.5 for M3 and 3.3 for M4 ;)


M3 = Nominal diameter 3 mm
M4 = Nominal diameter 4 mm

The key is in detail. Never clever to correct someone without reading their post. I was clearly referring to the nominal diameter of the screw body.

[Oliv996]

oOps sorry Glypo, it was just my 2 cents on the topic.... :blush::cry:

BTW with your considerations above, I agree with you calculation ;)

[Northy]

Ok, but if force x is put onto the purple wishbone pivot pin hangers, and is enough to bend the screws, if you put bigger screws in, and then apply force x again, isn't there more pain on the gearbox sides now as the screws don't bend to 'save' the gearbox sides? :confused:

G

[Chrislong]

i agree with you G, the force absorbed by screw bendages is transferred to another part. That could mean more broken wishbones, or bendages to the gearbox.

But also in theory the calculations make sense, but what is lost marginally is surface area of gearbox half by putting bigger holes in.

Personally, I can't see the gearboxes bendage-ing, so it'll be wishbones. But if running the mid-flex wishbones whats to say that we won't even bend m3 screws... :confused:

oh, there are just too many variables, and ive had too much wine to think about it. :thumbsup:

[glypo]

Oh right, I see your logic now and why you say more stress.

For sure, as the screws bend, they will absorb some force. However the screws don't bend too much, and even so they do not break. A breakage releases loads of energy.

The small bend will absorb maybe 2-5% of the impact energy, the rest has to travel through the transmission housing as stress and strain. And once they are bent, the extend to which they can bend further is limited so the transmission housing then takes 100% of the impact.

So I think this mod adds no extra stress really, and saves hassle of bent screws. I will test it out next weekend at the MK GP, that track will no doubt test their strength. Nice and easy to do too, you only need two drill bits and a M4 tap :)

[glypo]

But also in theory the calculations make sense, but what is lost marginally is surface area of gearbox half by putting bigger holes in.


Sorry for double post, you posted as I was replying. (I also have had a little to drink so replies seem to take longer with other distractions).

The hole cut makes no difference, as the gap is filled by the screw so there is no real strength loss in terms of that.

[bigred5765]

and a bigger leaver moment from the bigger screw, ie bigger bar easyer to bend,

[glypo]

and a bigger leaver moment from the bigger screw, ie bigger bar easyer to bend,

Nope. Moment = force x perp. distance from pivot.

The M4 screws I have used (high tensile steel cap screws) are the same length as the standard M3's.

[glypo]

Forgot about this. Anyway, tonight when putting my medium flex wishbones for the MK Racing GP tomorrow I remembered and took a couple of snaps.

M4 high-tensile scew mod. Takes 20 mins max - and hopefully will solve the issue.

http://www.glypo.com/reviews/sx/m4-2.jpg

http://www.glypo.com/reviews/sx/m4.jpg

[ashleyb4]

Any chance you could maybe put a hing pin straight the way though?

A

[glypo]

I see where you are coming from, and yes and no is the answer.

There are two mount points, you could put a pin through the first mount point, but the diff is in the way for the second. There is no movement at that point though, so no need for a pin, and it won't add much strength over a screw of the same diameter.

[sime46]

This looks like THE mod. Could you tell me the drill size to order for the gearbox sides ie the part that needs tapping? I assume you go 4mm in the pivots that they pass through? Cheers. This is a good solution I think.

[Oliv996]

This looks like THE mod. Could you tell me the drill size to order for the gearbox sides ie the part that needs tapping?

A 3.3mm drill will be perfect.

I assume you go 4mm in the pivots that they pass through?

Of course:thumbsup: and a 3.9mm drill will be more than enough ;)

[Northy]

I could look at putting a kit of bits required together if anyone is interested? :confused:

G

[glypo]

As above, and yes I used 4.0mm on the pivot blocks.

http://www.modelfixings.co.uk/

They sell M4 taps and the correct sized drill bit together I think. They also sell M4 high tensile screws. Ran my car all day today at Newbury, took some stupid crashes and not even slightly bent :)

Of course if Northy could do it all as a bundle would be ideal. If you are going to do it, 10mm and 12mm bolts are needed for front. I've not bothered with my back, not really needed I don't think. If I bend one, then I will.

[Swiss]

I was looking at completing this mod, but wanted to ask some questions. I appologise if someone has asked them before.

1. Tapping a M3 to M4. so do you first redrill the hole, then use the starter M4 Tap, the the finishing M4 tap? Or can you just go straight in the with the starter M4 Tap?
2. Are people re-tapping the front and back holes of the front gearbox?
3. Do you need a cutting fluid of some kind?

Thanks

Paul

[Oliv996]

1. First you have to re-drill the existing holes with a 3.3mm drill bit. Then I recommend you to use the starter M4 tap, because it's easier to place tap normal to diff housing and you will do a better tap job.
2. Yes both
3. I usually do tap job with cutting fluid, but in aluminum material it's quite useless

[glypo]

As above, but you need to remember to enlarge the pivot blocks too so the screws can go right through.

And you never need cooling fluid to drill a small hole is basically any material! Cooling fluid is for machining jobs.

[rcracer]

doesnt it weaken the pivot blocks as i am seriously thinking of doing this mod as i dont think i can afford the upkeep replacing the bent screws :lol:

[Chrislong]

How often are you bending them Neil? Ive slightly bent my front screws once, and the rear ones only after a huge crash, and the car has had a lot of use now.

If they come loose during a race then they become more prone to bendages, so do use thread lock and keep checking them. i check mine after each race, its quick to do with an L shaped allen key - no need to take wheels off.

Chris

[rcracer]

Did 2 yesterday and 2 at york indoor series, i do threadlock them in and they dont seem to be coming loose maybe i am just a crap driver and hit everything :blush: i bent one side so bad a few weeks ago it broke the outdrive.

[Northy]

Are you guys using M3.5 or M4 screws?

I can look at putting a kit together if you want, never got round to it :cry:

G

[footey]

chris i now paul c is bending them after every run nearly

[glypo]

High tensile m4, and its much better for it.

[chris68nufc]

Im bending mine nearly every run. I would like to get a kit together to do it. This fricking car has cost me fortunes.:cry:

[Oliv996]

As above, but you need to remember to enlarge the pivot blocks too so the screws can go right through.

And you never need cooling fluid to drill a small hole is basically any material! Cooling fluid is for machining jobs.

Hey mate, please pay attention on the difference between cutting fluid and cooling fluid. Cutting fluid may be not only a cooling fluid, it also could be design to lubricate the tool, and it's very useful (especially with low cost tools) for tapping or drilling jobs in many material. Mineral oil is basically a good start ;)

[Swiss]

Run my car with the M4 screw mod on the front today, and broke one of the rear wishbone hangers.. Just a thought, but by beefing up the screws are we just transferring the force of impact?
If this is the case usrely it would be better to bend an M3 screw than snap a w/bone hanger?

[mharlow]

I have completed the M4 Mod on my Cat SX and have had no problems at all since doing it. Does anyone know where I can get M4 washers in 0.5mm & 1mm thicknesses?

[Chrislong]

The M4 washers sold by Schumacher for the wheels are 1mm (from memory).

Perhaps Nortech can source 0.5mm? Que G.

[Jamie B4]

Think microtech does these as well

[Bungleaio]

m4 washers & loads of different screws here http://www.stagonset.co.uk/fasteners?cart_id=1025114_1731&prm_grp=A2_Washer_M4&summit=M4|Washers

[DaveG28]

How many are making the M4 mod? Tempted to just stack up on M3's from Nortech!

[Northy]

If this is the case usrely it would be better to bend an M3 screw than snap a w/bone hanger?

I've seen one animal snap them while using M3 screws, so I'm not sure M4 is a great idea TBH.

G

[PaulUpton]

yep ive broke a few wishbones using the original M3 screws!

[Chrislong]

I've seen one animal snap them while using M3 screws, so I'm not sure M4 is a great idea TBH.

G

I broke a wishbone hanger - the rearmost one, not the 10deg block. But I did hit a car flat out on the straight - the list of broken parts was long (but Wishbone survived!), and im still finding things twisted now after I thought id fixed it. :cry:

[Northy]

I broke a wishbone hanger - the rearmost one, not the 10deg block. But I did hit a car flat out on the straight - the list of broken parts was long (but Wishbone survived!), and im still finding things twisted now after I thought id fixed it. :cry:

Make that two animals then...... :woot::woot:

G

[ben]

3 animals :cry: Ive done a couple of the rear hangers with the M3 screws.
I did the same thing as chris and hit a car flat out on the straight, the broken parts mounted up... but no broken wishbones:lol: that was with medium flex btw.

[Northy]

You were animal no.1 :p:p

G

[Oliv996]

Here is a solution to avoid bending front screws:

http://img17.imageshack.us/img17/6636/img1182t.jpg

It requires to mod front bumper ;)

[ice-nine]

Nice job on that. Hopefully, Schumacher or someone produces that, as well as a bumper, as a kit, certainly addresses the problem! :thumbsup:

[stegger]

Nice job on that. Hopefully, Schumacher or someone produces that, as well as a bumper, as a kit, certainly addresses the problem! :thumbsup:

It's in hand i should have one by the end of the week ;) and then depending on interest i will get some costings because i have somebody too produce them :thumbsup:

[ben]

We had a brace identical to that on the 24 hour endurance car :thumbsup: