Scratch Building In Brass - comments invited

[Enterprisingwestern]

1 hour ago, doilum said:

This is another job for the rivet drop tool.

 

Even that can distort brass.

 

Mike.

[doilum]

2 hours ago, Enterprisingwestern said:

 

Even that can distort brass.

 

Mike.

Only a tiny dint is needed to get a 1mm pilot started.

[Enterprisingwestern]

3 hours ago, doilum said:

Only a tiny dint is needed to get a 1mm pilot started.

 

Hence why I use my method!

 

Mike.

[wagonbasher]

Tonight I tried my first score and snap.  I used a Stanley knife (maybe a bit heavy but its that or the scalpel today.  It worked ok.  I was only squaring up the brass sheet.  Bending bars appear to be ideal for this,  following another thread I bought some 12mm x 12 mm bar from B&Q to make my own bars [£7.30] not all of their bar has defined edges.  I will try to drill down and tap the lower bar, failing that, two big clamps.

 

maybe some photos at the weekend.  

 

Andt

[Londontram]

Very much enjoying this thread also picking up some usefull hints and tips.

 Steve

[wagonbasher]

I still owe you some photos, but to close off the bending bars.

 

so, it turns out it was 14mm x 14mm steel bar from B&Q at £7.30.  I trimmed off the ends, the manufacturers cutting process had distorted the ends a little.  Then cut the bar in half.  I clamped the two bars together one on top of the other between two pieces of stripwood.  With a pillar drill I drilled down though both Bars, gradually increasing the bore to 5mm. I tapped the bottom bar with a M6 tap and then opened out the hole in the top bar to 6mm.  I made sure that the ends of the bars and all of the holes were free of burrs.  I bought some 25mm M6 bolts ( I think they call them cap heads) sort of raised head, knurled with  a hex key hole.  They cost £1.50 from Amazon (free delivery).  So I think the bend capacity is about 14 inches.  I don't think that is long enough for a 7mm coach side but I'm not making any of them...  

 

i have practised and what what I am pleased about is that the sort of hex shape at the front of the tram can be bent  along a score line rather than formed with separate pieces.  You couldn't do that with a grater angle but it will work for the tram

 

photos to follow.

 

Andy

 

 

[wagonbasher]

On 30/09/2020 at 06:53, wagonbasher said:

I still owe you some photos, but to close off the bending bars.

 

so, it turns out it was 14mm x 14mm steel bar from B&Q at £7.30.  I trimmed off the ends, the manufacturers cutting process had distorted the ends a little.  Then cut the bar in half.  I clamped the two bars together one on top of the other between two pieces of stripwood.  With a pillar drill I drilled down though both Bars, gradually increasing the bore to 5mm. I tapped the bottom bar with a M6 tap and then opened out the hole in the top bar to 6mm.  I made sure that the ends of the bars and all of the holes were free of burrs.  I bought some 25mm M6 bolts ( I think they call them cap heads) sort of raised head, knurled with  a hex key hole.  They cost £1.50 from Amazon (free delivery).  So I think the bend capacity is about 14 inches.  I don't think that is long enough for a 7mm coach side but I'm not making any of them...  

 

i have practised and what what I am pleased about is that the sort of hex shape at the front of the tram can be bent  along a score line rather than formed with separate pieces.  You couldn't do that with a grater angle but it will work for the tram

 

photos to follow.

 

Andy

as promised

On 30/09/2020 at 06:53, wagonbasher said:

 

[DGO]

I was going to ask how you'd got the corners to be sharp on the steel bars but I can see from the pics that you didn't, If you don't get rid of the radii on the bending bars and you use on etched kits where the bend lines are half etched you won't get perfect corners which is likely to result in a poor fit 

[wagonbasher]

3 hours ago, DGO said:

I was going to ask how you'd got the corners to be sharp on the steel bars but I can see from the pics that you didn't, If you don't get rid of the radii on the bending bars and you use on etched kits where the bend lines are half etched you won't get perfect corners which is likely to result in a poor fit 

OK

 

They are quite small radius but I take your point.  Some of the steel bars in B&Q were more rounded than these.  Without a milling machine I don't think there is a way of squarely taking out the small rounded corners. So far I have used them to score and snap sheet brass, I am scratch building so no etches involved.  There is no indication of bending before snapping, but a knife cut is thinner than a half etch.  I've used it on 16 thou sheet, maybe at a thinner gauge  it might bend round the radius before snapping.   I have also tried just bending the score lines to about 20 degrees as that suites parts of the prototype, again very crisp angle, you couldn't bend much more without removing more material on the inside of the bend.  It cost me less than a tenner and was quite enjoyable to make, the nice thing about scratch building rather than using etched kits is that you can just do it again a different way.  You haven't ruined part of a kit, you just made a piece of brass for the scraps box. If it doesn't suite some applications then I will use something else.

 

By the way, I'm not knocking etched kits, trust me if there was someone making etched kits of steam trams I wouldn't be making one from scratch.

 

Andy

[DGO]

fair enough, by the way you could probably use a grinding machine rather than a mill if it's only a small radius, however if it's working for you I'll not say any more on the subject. 

 

[Enterprisingwestern]

 

Angle iron tends to have proper sharp right angle corners, or at least it did back in my day. (Yes, the Victorians were very skillfull!)

 

Mike.

[DGO]

1 hour ago, Enterprisingwestern said:

 

Angle iron tends to have proper sharp right angle corners, or at least it did back in my day. (Yes, the Victorians were very skillfull!)

 

Mike.

Hot rolled equal or unequal angle steel to BS EN 10025:1 should have a sharp outer corner, whatever size. Only issue is that it tends to come in long lengths, most metal centers will cut it for you, some will even cut short lengths, 6M of 13 x 13 x 3 is under £15, I guess if I were being clever I'd design something with toggle clamps rather than screw threads so if I were doing a lot of the same thickness I'd just have to throw two toggles rather than screw in and out a couple of bolts

 

Edited October 2, 2020 by DGO

[Enterprisingwestern]

3 minutes ago, DGO said:

Hot rolled equal or unequal angle steel to BS EN 10025:1 should have a sharp outer corner, whatever size.

 

Agreed, but we are talking B&Q here, their timber isn't worthy of name so I doubt there metal is any better, they only know price, quality or standards don't come into the equation.

 

Mike.

[DGO]

Also one disadvantage with hot rolled steel, it's likely to be coated in scale, of course you can always remove that with Hydrochloric acid which does at least not require machining LOL

[wagonbasher]

I bent and snapped some more parts today and release that I was / am subconsciously placing the brass cut mark a little deeper than the edge of the steel, only by 1/2mm or something but I am obviously compensating for the little radius.  It still works fine and I did some 10 thou this morning, that snaps very easily. 

 

I don't know about scale on the steel, there is no sign of anything coming off, but then I don't know what kind of steel it is.

 

Andy