The fact that they may screw together does not make them the same.
That is a lovely machine. I would love one.
I didnn't say they were the same. I said they had different thread angles.
True but the fact that they are not the same doesn't mean there's no correlation. For example, many of the thread diameters and pitches for BSW correlate with the thread diameter and pitches for UNC. Now, depending on the quality of the fastener, or it's state of wear, it's very possible that a mis-matched thread type will be no worse fitting than the correct one. Not only that but for the majority of applications it simply doesn't matter.
I know this might be hard to rationalise for someone who has worked long in the aviation industry (where it most definitely DOES matter) but the simple fact is if all you're doing is screwing a panel to your lathe or mill putting a 1/4" UNC fastener into a 1/4" BSW threaded hole is going to work just as well as a 1/4" BSW fastener when all it's doing is holding on your splash guard.
That is a fair and valid point to make. However, we have to be very careful making statements of the sort along the lines of BSF/W and UNF/C are the same.
It's not hard to get any type of fastener, unf, Unc, whit or whatever in these days of Internet purchasing. So why you'd mate up different thread systems, deliberately, is beyond me.
Thread file would be a good investment, you might be able to save a lot.
Agree with Carl, the are UNC/F fasteners, I have the dedicated vertical version.
Hi Carl and all Guys which are helping me a lot at the moment.
I be honest, I was really struggling to buy this lovely machnine. This type of machine is not really popular in Germany and it is really very hard to find an owner of a Harrison.
But luckily I bought it and this was thr right desionion. This is exatct the size of miller I needed.
And now I am more than happy lading here in that very nice forum. Thanks on all
Ok, now I understoood that I have to use UNC (normal thread) and UNF (fine thread). Carl I went throuhg your thread, this is brilliant. I think you can help me a loot if it comes to technical problems.
I did a survey with a micrometer yesterdy. I wanted to check the alignment of all levels (x and Y). All looks really good to me.
I will do just samll repairs and a new painting. Is RAL6011 the right color for that machine? It seems so I couls not find any other color chart on it.
The only thing which worries me is the z-spindel mechanism. It goes smoothly downwards, but upwards the handle is a bit hard to turn. And the play on the handle between up and downwards is a bit much. But I will lubricate all elements at frst and than I will see the results.
There are quite a few people on this site who have these Harrison mills. They will tell you that they are good, solid machines. I haven't used mine yet as I have a lot of work still to do on it.
I guess in Germany Deckel machines may be more common? My brother has an Emco lathe which I'm sure are also popular where you are.
The Z axis handle is stiff on my machine too. The mechanism consists of helical gears driving a leadscrew. It tends to get stuck up with dirt and cuttings from the machine. Also the casting that holds the leadscrew nut for the z axis can crack, so it's worth checking.
A note about the paint. Not sure what the RAL number of the colour is. However, this is the correct colour and is what I'm using in my restoration:-
mine is not Harrison Blue/Grey.
Mine is paunted in RAL 6011 Reseda Green.
All German machining tools were painted in that RAL color chart. ....very common.
Now the question is, did Harrison change the color for Export?
I don't know if they changed the colour. It's like the colour of an Emco or Schaublin machine.
I have a Harrison M250 lathe from the 1980s. It is beige, which is the colour they mainly used in the 80s. They came in other colours later on. I've never seen a pre 80s Harrison machine that wasn't grey, unless repainted by the owner.
Because in the real world where Joe Bloggs is screwing a bracket onto his milling machine, interchanging BSW and Unified makes not a jot of difference, the tolerances make sure of that.
I'm also in aviation and wouldn't dream of using the wrong thread system at work, at home in the workshop it's not always so easy to differentiate between 55° and 65° on a 1/8" diameter fastener...and some manufacturers have BOTH systems!!
You are getting all worked up about thread systems and paying no mind to the other critical part of fastener makeup...material. it's just as important for a fastener material to have the same physical properties as the one it is replacing but you've very little chance of finding that information most of the time.
You wouldn't have used soft solid rivets in place of hard and vice versa (unless of course your maintenance documentation allows for such)
You have a lot of No. 5 UNC fasteners in your shed then?
Your point is well made, but your example is ill-chosen.
How so? A 5-40 screw will go in a 1/8 bsw hole and vice versa.
Because 5-40 is relatively uncommon? Even more reason why you might want to interchange.
This os my green lady.
Made for Germany.
I don't have this handle for the motor clutch.
Could I ask that we don't scare away a new member by disagreements of pitch and threads of screws/bolts.
If you want to have a discussion of the minutiae of various fixings start a new "Thread"
@Guzzi Fuzzi Nice Pictures
How dare you be so reasonable.
I change my suggestion of buying Whit/BSF taps and dies to buy yourself a set of UNC/UNF taps and dies!!
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