Whats The Difference?!?

[Guest oddsocks]

Whats the difference between metric bolts and unf bolts? How can you tell? What about set screws and bolts, can you use a set scew on your build as long as its 8.8? Been to local shop to get some bolts and noticed he's given me set screws, i what them for rear hub and discs, can i use them?

 

I've also got a t piece from gbs and a stop switch from ebay that seems a bit tight before it gets started-wrong thread?? Can i re-tap it without damaging switch?

 

Link removed as asked

 

 

Here a link not sure if its worked tho.

 

J

[Guest dinger]

Repaired link

 

switch

 

 

The 4 way t piece should be m10 thread, I'd say the switch you have bought is an imperial thread as the old mini's and MG's are oldy worldy.

[Knock-on]

UNF is the middle thread pitch of UTS which is the American standard. I don't know a lot about it as predominantly use metric but I think the nylocks are white where metric is blue which is one way of checking.

 

I would suggest sticking to metric as much as possible for continuity but there's nothing at all wrong with UNF. If you have the same harness as me, you will probably use a few anyway.

[Guest oddsocks]

UNF is the middle thread pitch of UTS which is the American standard. I don't know a lot about it as predominantly use metric but I think the nylocks are white where metric is blue which is one way of checking.

 

I would suggest sticking to metric as much as possible for continuity but there's nothing at all wrong with UNF. If you have the same harness as me, you will probably use a few anyway.

 

 

So can you re-tap the UNF thread into metric? Or do i need to buy another switch?

I did email the guy to ask if it was M10 but no reply so i though i'd take a chance-but i lost!

[fry61]

Please don't retap your brake switch, 'cos no brake switch in hole = no brakes.

[Guest oddsocks]

Please don't retap your brake switch, 'cos no brake switch in hole = no brakes.

 

Good point! Guess im gonna have to another one hopefully i'll buy the RIGHT one this time!

Anyone need a UNF fitting brake switch???

[Guest Botbuilder]

Whats the difference between metric bolts and unf bolts? How can you tell? What about set screws and bolts, can you use a set scew on your build as long as its 8.8? Been to local shop to get some bolts and noticed he's given me set screws, i what them for rear hub and discs, can i use them?

 

I've also got a t piece from gbs and a stop switch from ebay that seems a bit tight before it gets started-wrong thread?? Can i re-tap it without damaging switch?

 

clicky

 

Here a link not sure if its worked tho.

 

J

Set screws have the thread running right up to the base of the head whereas set bolt have a plain section under the head. Set screws are OK to use provided nothing is rotating on the shaft of the bolt (suspension bushes etc.) The differences between UNF and Metric can be found in a cheap little book called Zeus, available from you any nut & bolt or engineeing supplier.You will find any of the bits that came from the donor car e.g. brakes, engine, steering etc. are all UNF or UNC if it was a Ford unless the donor car was really modern, if the donor was japanese or continental it will be metric. All the other stuff that people have bolted on like body panels and suspension will probably be metric.

 

It makes life a little more complicated and if your Hood is anything like mine you always need two sets of spanners one Metric one AF and if you're really unlucky like me Whitworth as well.

[Redspec]

You will find any of the bits that came from the donor car e.g. brakes, engine, steering etc. are all UNF or UNC if it was a Ford unless the donor car was really modern

 

????? Mine was a 1990 donor (Ford) and only metric, at least all the bit's we have used??????

 

Steve

[agent_zed]

Am i correct in thinking that the brake switch is a pressure switch that is normally screwed into a t piece? If so i see no reason why you can't just make up a converter pipe. If you get a metric male end (10mm) to go into your t-piece and a unf female for you switch and a bit of brake pipe in between.

 

Can anyone else see a problem doing this? i'd keep the pipe as short as possible to avoid air locks, but i guess that would depend on the brake flaring tool as to how close you can get each end.

 

hth

[ibrooks]

The only problem you are likely to come across with this method is as you say air-locks as you will effectively create a dead end with no way to bleed it. To get round this the same method could be used with a slight addition.

 

Get a 3-way T-piece with UNF threads.

 

Make your short piece of brake pipe with male fittings on both ends (one metric to screw into the existing T and one UNF to go into the additional T).

 

Screw the pressure switch into the new T.

 

Put a UNF bleed screw in the third hole in the UNF T.

 

When bleeding the brakes just remember this one will want to be done first as it'll be closer to the master than anything else.

 

On the Sierra the brake fitings are all M10 fine threads. The pressure switch you have is likely from a British car and 3/8"UNF (older Minis like mine had them instead of a switch on the pedal).

 

 

 

Ali G - there are very few imperial fasteners on the Sierra. Seatbelts will be 7/16"UNF and depending on the engine some of the tappings into the block will be UNC as the engines pre-date the cars by a long way and are of American descent. It's always useful to have a full set of spanners and sockets anyway though as a rusty M8 bolt should have a 13mm head but once you've scraped off the layer of rust it's quite often a little smaller and a 13mm socket or spanner will just round it off a 1/2" spanner or socket will often fit perfectly though because it's 12.7mm.

 

I can highly recommend proper surface drive sockets though. As well as being six sided (sort of) and therefore less likely to just take the corners off a nut or bolt they have quite a bit of flexibility over the size of hex that they'll get a grip on and so can get you out of a hole when you come across that odd fastener that you don't have anything else to fit.

 

Iain

[Guest smartfazer]

The only problem you are likely to come across with this method is as you say air-locks as you will effectively create a dead end with no way to bleed it. To get round this the same method could be used with a slight addition.

 

Get a 3-way T-piece with UNF threads.

 

Make your short piece of brake pipe with male fittings on both ends (one metric to screw into the existing T and one UNF to go into the additional T).

 

Screw the pressure switch into the new T.

 

Put a UNF bleed screw in the third hole in the UNF T.

 

When bleeding the brakes just remember this one will want to be done first as it'll be closer to the master than anything else.

 

On the Sierra the brake fitings are all M10 fine threads. The pressure switch you have is likely from a British car and 3/8"UNF (older Minis like mine had them instead of a switch on the pedal).

 

 

Iain

 

 

Iain,

 

Good idea, well thought out but in my mind it could be a little over engineered.

 

It would be easier, and maybe cheaper in time and money, to buy a metric pressure switch and install that.

 

It will make bleeding the brakes much simpler as well.

 

Steve

[Bob Tucker]

My XE engine has ARP head bolts.

ARP are US based.

So what tool did I need to change my head gasket?

 

a 1/4 drive (1/2 wont fit into the head casting) 1/2" 12 point socket......

Took a bit of finding....

Bob