SF orifice disk thickness

[Old Grey]

Does anyone know the thickness of SF orifice disk, and is it just sitting the internal wooden board - how is it mounted -

[Old Grey]

I will answer this question myself for the 86 people that showed interest in the topic. The answers were in other posts, so I will surmise them here.

Actually, no I never have measured the SF600 plate so I was not able to post this info. The plate hole dimensions were supplied by someone else to me but not the thickness. I'm sure you could research at what thickness SS warps from laser cutting, I lathe cut all my orifice plates so I would not be able to supply that info so I did not reply.

A bit of advice for people who don't have laser cutting experience. No one can actually predict warpage with thickness, because it's shape dependant - my disk is more warped near the small holes than the large holes -. You can touch a plate right after it's cut, and it's only warm, but laser is concentrated heat, so it will still warp thin plates. Also the person cutting has a different interpretation of how much warp is warped - I told him to use a thickness that wouldn't warp, and even though he thought the 1.2mm wasn't warped, it was warped more than I wanted -. If I was to guess I would say the SF600 disk couldn't be thinner that 1.5mm - their SF1020 test plate is 1.5mm -, and if they did use 1.5mm, the warpage might be acceptable.

[Old Grey]

I did some scratching around and asked Bill Jones, the nicest most genuine guy I have conversed with on Speedtalk, and this is the conversation.

I was wondering if you could help.

I remember you opened up your SF-300 to change the motor brushes, and was wondering if noticed how the orifice disk was mounted.

I remember someone saying it was spring loaded to the centre board, but if it was spring loaded down it wouldn't spin as easily as it does - or as easy as it did on a SF-600 I used once -

-I don't see how it is spring loaded any where.

-the large rotating brass disk just lays on the slanted plenum floor (slanted about 45 degrees)---same angle as the front slanted face section of the flowbench.

-there is piece of steel like about the top 60% of a hexagon stop sign bolted down over it and sealed around the outer edge of this piece of steel.

-this 60% hex looking piece has one hole a little larger than the largest orifice and centered in the upper section of this hex piece.

-I don't know how this plate is spaced up but there are 6 bolts that go down thru the hex piece into the angled wood panel of the cabinent.

-I assume there is another plate of some sort on the under side of the slanted wood panel----maybe just some lock nuts on the underside---I'm not sure.

-it looks to me like a nice fitting joint with a slight amount of freedom
so the plate will rotate freely with minimum leakage.
--------------------------------------------------------------
-there is a design flaw in the flow bench where the detent lock pin for the 6 different flow ranges ends up leaving a trail around the entire diameter of the rotating disk after years of time---and this trail looks deep enough to possibly allow a little air leakage---and edge demarcations or dent like marks on the ID of the larger orifices in two places.
-----------------------------------------------------------------------------------
-I really don't know how it is connected to the pivot pin----this pivot pin is the reason for the extra 10% length of the hex steel piece---so there is a place in that extra 10% length for the pivot hole.
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[1960FL]

I will answer this question myself for the 86 people that showed interest in the topic. The answers were in other posts, so I will surmise them here.

So what is the actual measured thickness of the SF Rotating disk?

I did not see anything but an assumption of 1.5MM.

Rick

[Old Grey]

I will answer this question myself for the 86 people that showed interest in the topic. The answers were in other posts, so I will surmise them here.

So what is the actual measured thickness of the SF Rotating disk?

I did not see anything but an assumption of 1.5MM.

Rick

It explains it here

I will answer this question myself for the 86 people that showed interest in the topic. The answers were in other posts, so I will surmise them here.

Actually, no I never have measured the SF600 plate so I was not able to post this info. The plate hole dimensions were supplied by someone else to me but not the thickness. I'm sure you could research at what thickness SS warps from laser cutting, I lathe cut all my orifice plates so I would not be able to supply that info so I did not reply.

A bit of advice for people who don't have laser cutting experience. No one can actually predict warpage with thickness, because it's shape dependant - my disk is more warped near the small holes than the large holes -. You can touch a plate right after it's cut, and it's only warm, but laser is concentrated heat, so it will still warp thin plates. Also the person cutting has a different interpretation of how much warp is warped - I told him to use a thickness that wouldn't warp, and even though he thought the 1.2mm wasn't warped, it was warped more than I wanted -. If I was to guess I would say the SF600 disk couldn't be thinner that 1.5mm - their SF1020 test plate is 1.5mm -, and if they did use 1.5mm, the warpage might be acceptable.

I will summarize.
NO one measured the disk, and if you want to duplicate it with laser cutting, it MIGHT be 1.5mm or thicker based on the pieces that were cut for the MSD.

The laser cutter that we used might have the laser set higher than SF, so the SF might not warp as much for the thickness. The brown edging on the face of their test orifice cuts is pretty close to the ones I have here, so just by feel I would say it would have to be 1.5 because our 1.2 and 1.0 bent by a considerable amount.
There is no zoom-in of the cut - can't see brown edge on face or grey cut on side -, so we don't really know if it is laser cut anyway.
If it's cold cut, it could be quite thin.

I would feel confident at 2.0mm with laser, but that's an opinion so it's only a starting point.

[Old Grey]

Bill Jones is a legend. SF-300

[1960FL]

Again, Based on our prior discussion your dissatisfaction with one not posting proof and valid information on a topic!

You started a thread asking for "Does anyone Know the thickness of the SF Disk?

[quote][/Does anyone know the thickness of SF orifice disk, and is it just sitting the internal wooden board - how is it mounted -
quote]

So for all those trying to figure this out the answer by coming to this thread; We still do not know! and Bill Jones though a great guy and well revered in our community did not validate 1.5MM and or laser cut, who knows they may be plasma cut or water jet???

Until a few people who have SF Benches put an arm and a micrometer in the hole and measure we just have no idea.

Rick

[Old Grey]

You must of missed all the edits, go back and have a read, or misunderstood.

It was a suggestion guide if you want to make a flat orifice disk using laser. Don't use thinner than 1.5mm is a start, which is better than nothing - saves you cutting some disks -. It wasn't a aftermarket SF replacement part duplication deal.

You could be right with plasma.

I was taking a closer look at the cuts, and my laser cuts are a lot cleaner, sharper, less browning, straighter, and a bright ss colour.
Looking at the SF cuts on the SF-1020 calibration orifice, the cut is dull grey, tapered, and more burnt. I spent half a year cutting with plasma in the 80's, and the quality of the SF is is pretty close.

Plasma is inferior to laser, more heat, more ragged cuts, so I would suggest laser as a substitute.

[Old Grey]

Comparing the cuts

Laser cut. Has slightly more burr on the cut, but it's easy to stone flat

SF-1020 cut


Slight radius on top, and tapered cut, looks like Plasma to me

[Old Grey]

This is Bill Jones's eyeball estimate of the brass orifice disk

I looked at that orifice plate and estimate the thickness to be more than .060" and less than .090"----probably about .075"---maybe .080".