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Member postings for fizzy

Here is a list of all the postings fizzy has made in our forums. Click on a thread name to jump to the thread.

Thread: Cutting a 1/2" bsp thread on Harrison L5 help
09/09/2021 19:53:52

using that c hart with the 3 speed gearbox i can get close to 14 tpi by using the closest metric equivalent but can it be made exactly - never done this before

09/09/2021 19:46:55

thanks Ady - that is indeed the thing i needed - having a bad day!

09/09/2021 19:46:03

forgive me, i thought it was all the info needed. I need to know what changewheel no of teeth and positiion to cut 14 tpi on the L5.

09/09/2021 16:43:42

Help needed with gear choice and configuration in otder to cut a 1/2" bsp thread on my harrison - not threadcutting gearbox - L5. Charts are on the machine but have worn away. Thanks

Thread: Steam boiler
19/08/2021 18:46:02

With a bore of 1" and a stroke of 2" you will need a lot of steam. A customer bought two of our 5" diameter boilers to run a ham radio generating set running twin Victoria engines which worked well. **LINK**

Thread: Taps and Dies
13/07/2021 20:17:49

A very basic rule I adopt when selecting dies which applies to tap and die sets is that if the die is split it is likely to be better quality than onw which isnt. No proff other than buying them for over forty years I have found this to be the case.

13/07/2021 20:14:56

You need the same pitch as your bolts - modt likely coarse

Thread: Machining Cylinder Head Chamber Roof - DIY or Shop Tool
06/07/2021 20:59:00

William, if your not intending to go for bigger valves then you are over thinking this. The modded chamber in the above photo has beed achieved using a high speed die grinder, ive done dozens of them and thats what they all look like. If all you are modding is the chambre you wont see much gain - the inlet throat is a nightmare design and requires extensive work. Get yourself the DV bible and all will be revealed. I can only assume you are turbocharging it as thats the only reason to open just the chamber and have such a low cr. Please do tell us what its for (sorry if you already have and ive missed it). Nostalgic stuff this is !

Thread: Model Engineer's Auction
01/07/2021 21:10:06


Thread: Machining Cylinder Head Chamber Roof - DIY or Shop Tool
30/06/2021 21:31:31

Thirty years ago I made good money modding 12G295 and 240 heads.Im assuming your increasing valve size? Cutter is easy to make if youve got a lathe - 120rpm. If your wanting high compression (13 to1 is as high as you go for normal fuel) then the chamber surfaces need to be ground smooth otherwise you will get detonation. Pillar drill - not a chance. An easier way to increase the seat size is with a conical grinder. If its just to lower the compression then die grinder - still got my Bosch die grinder somewhere - and wear goggles, forgot how many times I went to a and e with cast iton in my eye!

Thread: Steam operated drain cocks
14/06/2021 18:00:17

Duncan - I opted for no.1 as it has a much lower surface area when closed so whould require less pressure to hold it shut, but either way should work.....I think

13/06/2021 12:57:59

1. drain in

2. drain out

3. valve head

4. O ring

5. Gland nut

6. ferrule

7. Out of shot - live steam line

Simples - perhaps all that time spent trying to get them to work wasnt a complete waste! Whats not shown is that you will also need a steam relief valve to release pressure to operate the valve.

Thread: Cutting an exact diameter using a carbide tip.
12/06/2021 21:25:13

Agreeing with Andrew, we use nothing but carbide tips - you need the correct tip for the job but anyone who telly you they have to be deep fast cuts clearly doesnt know what they are talking about! No problem taking cuts of 0.0002"

Andrew - have you spotted your deliberate error? LOL

Thread: Bargain?
23/05/2021 20:16:20

I got a mixed box containing several hundred for under a tenner so im good for a while. What are these people on?

Thread: A Welding Problem - Steel Type?
23/05/2021 20:12:56

As an ex coded welder .....150 amps will struggle with 6mm plate even if its set up well and you are a very competent welder . Needs to be about 300 amps, spray not drip and 1.2 wire. What you are describing is what I would expect given equipment, material and experience

Thread: Bargain?
23/05/2021 20:01:18

Could be yours for only £38 ish - have I missed something?


Thread: Boiler stays
20/05/2021 21:24:43

If soldered correctly in the first place there is no problem in machining stays flat to the surface, the solder between the stay and the plate does all the work.

Whilst the regulations may require a permanent mark on the pressure gauge face plate, on smaller older gauges it is very unwise to attempt this as the retaining screws tend to corrode and snap off. New gauges come apart easily but must be handled with great care.

If your safety is unscrewing itself then something is badly wrong. As Nigel says, the spring should hold it plenty tight enough in place.

For most fittings I use fibre washers, but for brass plugs I use PTFE tape, and sometimes both if the direction of the fitting doesnt fall quire right. What a lot of people dont realise is that PTFE tape made for water pipes shouldnt be used for gas pipes. There are two types, one specifically for each application.

Thread: 10TB HDD
20/05/2021 12:22:56

hdd backup has had its day, and im glad to be rid of them after so many fails. Everything on my pc is automatically backed up to the ms cloud so i can access everything anywhere. Will the cloud fail - unlikely given who runs mine.

Thread: Shortening HSS drills
15/05/2021 09:07:01

Could you please provide an explanation of how stiffness (which is a function of Young's modulus and geometry) correlates to hardness. Thanks.

Lifted from the net - a bit vague but copvers the basics

The hardness (H) of a material tends to increase with an increase in the elastic modulus (E), yield strength (σy) and the strain-hardening exponent (n). Several materials with different combinations of elastic and plastic properties can exhibit identical true hardness (for a particular indenter geometry/apex angle). In general, combinations of materials that exhibit relatively low elastic modulus and high yield strength or strain-hardening exponents and those that exhibit relatively high elastic modulus and low yield strength or strain-hardening exponents exhibit similar hardness properties. Depending on the strain-hardening characteristics of the indented material, (i.e. n = 0 or ), the ratio H/σy ranges, respectively, from 2.2 to 2.6 or 2 to 20 (for indentations with a cone angle of 70.3°. The materials that have lower σy/E and higher n exhibit higher H/σy ratios. The commonly invoked relationship between hardness and the yield strength, i.e. H ≈ 3σy, is not generally valid or applicable for all power-law hardening materials. The indentation hardness of a power law hardening material can be taken as following the relationship H ≈ (2.1–2.8)σr where σr is the representative stress based on Tabor’s representative strain for a wide range of materials.

Thread: Shipping to the EU - update
15/05/2021 08:53:36

As far as im aware amazon dont operate a courier service unless you are buying an item from them - I wish they did!

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