Riffle angle

[chris t]

Hi jeff witch one is the 15 degrees would you use dumb question , I'm stumped can't think , please help .

[shivan]

If the sloped line is yours sluice running from A to B, then i believe B would be the one you want.

[chris t]

Yer B is the flat one and A is the upright one

[chris t]

So 15 degree is the best angle or can go a bit higher on the angle ?

[shivan]

The 15 degree angle is designed so the back of the riffle is just about upright when you take in the 3 inch per foot drop of the sluice. This information is based on the Clarkston study which uses angle riffles (L shape) i believe.
Cant find any info for flat riffles at the moment but will have another look a bit later.

[jeffu]

15 degrees from the vertical angled towards the head of the sluice is the ideal angle for Clarkson riffles.
If you are running standard Hungarian riffles, there isn't a set rule, although, if their angle is to low, they become nothing more than a speed hump. Better keeping the angle between 15 and 20 degrees off the vertical sloped downstream.

Clarkson's have been proven as the most efficient of all the basic riffle systems. BUT for the weekend fossicker, they can be a nightmare. To operate correctly they require a very precise setup. Waterflow, feed rate and levels are very important for Clarkson's to operate correctly. They can take half your day to get right.
I run Clarkson riffles in my large GoldPro highbanker ONLY when I am out for more than 2 days at a time.

Jeff

[jeffu]

Forgot about flat bar riffles.

Can be described in one word - useless.

Flat bar is only used in large alluvial sluices where bars of 100mm height are used as nugget traps at the very head of the sluice. When used as the principle riffles in a sluice they don't create an effective vortex and very poor low pressure areas.

Jeff

[chris t]

This is my set up they are set up at 4 inches apart do you think they should set up at 2.5 inches apart ? 

[golddiggerart]

This was my old banker, the riffles were perfect for catching heavies not that any Gold got past the nugget trap.

Actually it was Andy who told me to pan bottom 3/4 first and the nugget trap second, no surprise that bottom only had 2 tiny specks from cons and all the gold was pretty much in the top 20% of the sluice. 

The riffles and Banker were made by HardYakka - Dale...

[chris t]

Which one do you all think would be the best to use , yor help would be helpful ? 

[jeffu]

Hi Chris.

I am sure I have put this up for you before but in any case here it is again.



Although I have a huge preference for the Clarkson riffles, I wouldn't recommend them for the weekend fossicker. When setup correctly they are the most efficient of any of the standard style of riffles. They are however, very time consuming to get properly setup, if you are going out in the field for a day trip or even a full weekend they can be frustrating to get right. Very dependent on waterflow, feed rate and angle, all have to be perfect.

I only use my Clarkson's when I am out for at least a 3 day trip. I have interchangeable riffles for my big GoldPro HB.

Jeff

[chris t]

Thanks jeff the pictures are great , if you have these set ups , it would be good to see your highbanker in action , with a close look at the riffles in action .

[jeffu]

Hi Chris.

If you are ever coming up this way let me know, you will be welcome to tag along.
Most of my outings lately are only day trips and I take the Vortex Drop riffle sluice, now, that's something completely different. No matting, no riffles and little concentrate at the end of the day. Very interesting to watch it work.
BTW, I live in Canberra.

Jeff

[chris t]

Thanks jeff something I'll have to try and work out .