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Member postings for Jeff Dayman

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

Thread: micro switch
01/07/2020 15:56:25

Hi Ian, If possible, I would recommend changing to a modern enclosed microswitch. I have used Omron's D2F series in many projects with great success. About 1 UK pound retail, probably 50 p or less each from an Omron distributor in UK. Many styles of lever and terminals available, several operating forces and volt / amp combinations up to 5A at 250 VAC. These are good units with small size high performance and quality at a good price. No connection to Omron except as a very satisfied user. (if you still use a computer mouse chances are it has two D2F's in it, or a cheap knockoff of one - billions of them in service worldwide)


Thread: Thread identification
30/06/2020 02:45:40

Glad to hear you could get one Andy. Good luck with getting the CX500 back on the road. Great bikes.

Thread: Coronavirus, advice from ME
29/06/2020 20:54:25

"His last what?" Said the shoemaker.

Been some prime twaddle in Smoke Rings periodically over the last year or so from the latest chair occupant in the ed office.

Thread: Thread identification
29/06/2020 20:51:45

Do you mean it might be a thin nut rather than a half nut (in the sense of a lathe half nut)? seen plenty of CX 500 swingarm pivots with thin nuts but never a half nut. Ready to be educated.

Anyway rather than spend a lot of time making a special nut to retain the swingarm pivot, a critical component, I would suggest calling a Honda dealer, Honda bike breaker, or David Silver Spares to see if there is one available off the shelf (which will have exactly the right thread, width, metallurgy, finish, etc) and usually nuts of this type are not a lot of money from Honda or a breaker. You will need model and serial number off the plate on the frame, usually near or on head bearing tube of the frame, for the firms to look up the part number.

Thread: Camshaft
25/06/2020 12:15:10

As far as I know, nobody yet offers a 3D printer and filament to make hi temp nylon alloys, polyphenylene sulfide, or polysulfone plastics. These are the big three candidate plastics for high heat high load applications. I think the pistons in the Ford plastic engine mentioned in an earlier post were polyphenylene sulfide with a ceramic insert on the hot side.

These plastics are available in rod and block form for machining parts out of, but they are expensive. Boedeker in USA is one supplier.

Stratasys in the USA is making 3D prints in Ultem polyetherimide, and has done for years, these are good to 200 deg C service. I just ordered some printed guard boxes for hot electrical components for a client in this material last week.

The major problem with plastics for engine cyls and pistons and valves is that they don't conduct heat well and they have high friction when running against each other.

A steel wet liner in a PPS block though, and a PS piston with PTFE faced ceramic side slippers and a ceramic top insert......maybe........

Thread: Gear Generator
24/06/2020 17:58:42

"He" will need the extra income if he has a BMW

Thread: Halifax 524 Headstock
24/06/2020 17:56:24

I'm with Phil, I think the headstock can be fixed with no loss of accuracy. Ways look intact. Looks like lots of metal below the broken bit that could be used to take some threaded holes for longer bolts up from the bottom under the bed anchor plate. For alignment across the bed, maybe a new block close fitted to the bed gap could be used, fastened to a plate bolted where the broken bit is, with adjuster screws like a tailstock adjuster. (The mounting screws could pass through this lot in large clearance holes.) The across-bed alignment would only need to be set once during centres alignment after the repair, then locked in place with setscrew-on-setscrew method. New anchor plates headstock to bed can be made also, if need be, from cast iron bar or mild steel.

As long as the ways on the headstock and the bed are not broken out it can be saved and will make lots of good work for years to come.

Thread: Camshaft
24/06/2020 12:14:17

Briggs and Stratton have had plastic gears and cams in their high volume production engines for at least 18 years. I had one such engine on my mower for 17 years, used 2 1/2 hr per week about 6 mo of the year. Never had a minute's trouble with that engine's internals, and it was running perfectly when I sold it. Last year I had an identical one 18 years old cross my workbench with extreme cylinder and valve guide wear, from running in a sandy area without an air filter for several years. During strip down I noticed that there was no visible wear at all on the plastic cams or gear, they looked just like the day they were made.

Intuitively after years working in the plastics / tooling side of industry I would say plastic was not a good choice for engine gears and cams but it obviously works when engineered for the loads and temperatures it sees with the right type of plastic, the right lubrication, etc. Nothing wrong with it if done correctly, in my opinion.

Thread: Grade of soft solder required to achieve a nice rounded fillet
22/06/2020 21:58:22

Heat level and flux used will also play a part in how the solder runs/fillets. 50/50 lead/tin solder gives good workability/ fillet size control, but may be hard to find nowadays with its' lead content. Auto body lead alloy has similar workability.

Modern no-lead plumbing solder is very difficult to use when fillets / appearance are a concern, and any flux bought for use with it is rubbish (in my experience)

Thread: Comparative Strength of Loctite
22/06/2020 16:29:14

Simon Williams - Are both parts joined in your test mild or plain carbon steel with low nickel content?

Did you degrease thoroughly with effective degreaser (ie immerse/rinse in acetone, laquer thinner, alcohol, several times) before Loctite application?

Did you use Loctite primer?

What was the gap between parts prior to applying Loctite?

Was the application and cure time at 20 deg C or above ambient temp?

All of the above can affect joint strength for Loctite.

I'd say 55 foot pounds torque is still a pretty respectable result! Good to see some real life testing going on. Well done!

Thread: How to cut a tri-lobe bore in a change gear (Schaublin style bore)
16/06/2020 02:58:46

Clive Foster - The locating pins would NOT be cut away - suggest you read my post again - clearly says "clamped located at the pins, PINS REMOVED, cuts made". I did mention making and using a sub-table.

As I also said "careful measurement and planning before any cuts are made" is important. Until that is done, and the OP knows what geometry he is dealing with, it is difficult to plan tooling and cuts.

This geometry is NOT the same as the generated epitrochoid shape in a Wankel engine housing, not sure why that was mentioned.

Thread: Machining a Fowler Cylinder Block
16/06/2020 00:06:28

Probably done originally with a shaper, in a couple of setups with the block at a compound angle to the ram. I'd be surprised if a positioning fixture or two was not used to position the block quickly at the right angle. Maybe they did one side on one shaper and the other side on a second shaper, with dedicated holding fixtures left set up on each. A gooseneck style tool holder could be made any shape to reach from the ram over walls of the steam chest, where the shaper stroke was adjusted for just the cut length needed for the valve faces. In a shaper you only need the width of the toolholder, plus a small clearance, between end of cut and adjacent wall at each end.

Many factories had rooms full of shapers years ago, before milling machines gained popularity.

The old saying "you can make anything with a shaper - except money" (they are slower than other tools at removing metal)

Thread: How to cut a tri-lobe bore in a change gear (Schaublin style bore)
15/06/2020 23:56:22

If you have access to a rotary table, you could drill the three corner holes first, then mount the gears off centre on the rotary table and remove the waste with three arc cuts. If you made a sub-table for the rot tab with two pins close fitted to two corner hole centres the gears could be positioned and clamped located at the pins, pins removed, cuts made. Careful measurement and planning before any cuts would be the order of the day I think.

Thread: What Did You Do Today 2020
15/06/2020 21:09:51

If 3D printing brackets from PLA for holding steel QC toolholders / tools - a suggestion - make sure there is something soft below them to keep them from getting damaged when the PLA lets go and the items being held fall. Don't ask me how I know. PLA is very handy for many things and is pretty good in compression and light loads. Tension, over time, with heavy items, not so much.

My PLA paintbrush holding pieces on my peg board are doing beautifully, holding up like the very rock of Gibraltar. Total load about 30 grams. smiley

Thread: Starrett type clamps
15/06/2020 04:06:26

Your metal supplier may in fact have 15.88 mm bar - craftily marketed as 5/8" or .625" bar smiley

I also doubt many people would work to the last .001 mm for a clamp, but digits are cheap on calculators today, so not a major stumbling block to leave them on dimensions, usually.

Personally I am grateful to Stew for making and sharing the drawing, as I am not likely to own one of the original clamps to be able to measure it, and as far as I know no other drawing of them has surfaced.

15/06/2020 00:25:06

Could be because many model making and home workshop people outside the USA now work in metric, and many can only buy materials and fasteners in metric.

If you want to work in inches, you could print the drawing and convert the sizes shown by dividing by 25.4.

There are only a few dimensions - it is not a big task to convert the drawing. But why not use the project as a way to learn something about metric? You may really enjoy working with metric units and threads.

Thread: Wooden Gears
14/06/2020 15:17:46

For different toys I have made for young relatives I cut the gears from good quality aircraft 5 ply plywood. This effectively solved the grain issue with the gears, which were very lightly loaded. The glue used in the plywood was very good, no delamination during cutting or in use occurred. Just food for thought.

Thread: Generating force to cap beer bottle
12/06/2020 22:48:00

The ancient and humble straight line action toggle clamp comes to mind. They are available from many makers in forces from a few pounds to 800 pounds force. Simple mechanical devices that last a while and do not cost much. A good brand is De-Sta-Co. Google is your friend. McMaster Carr have accurate CAD models of many.

Fine adjustment of position of delivered force can be easily done with a screw and nut adjuster in the end of the clamp plunger attaching to whatever "pusher" piece you are using.

Note - if applying high forces to glass bottles it is a good idea to hold them dead square to the force applied and hold them firmly. Otherwise the device becomes a bottle neck breaker rather than a bottle capper.

Thread: Removing gunge
10/06/2020 12:45:46

If burning any plastic as AdrianR mentioned, use extreme caution and do so outdoors with the wind taking away from you any fumes, preferably in an area with no people downwind for several km. I would recommend using a respirator mask rated for VOC's and particulates. The fumes from many plastics when burnt are extremely toxic , some are carcinogenic, and breathing them can cause illness or death depending on time of exposure. Please be careful!

Thread: Finnished prodject during lock down.
07/06/2020 16:00:40

Looks great David! well done.

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