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Member postings for JasonB

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

Thread: The Workshop Progress Thread 2019
13/10/2019 13:03:22

Is it working now?

13/10/2019 12:24:12

I got all the Midget parts finished, 57 individual items plus a further 30 custom made nuts, screws etc.

Luckily I remembered how it all went back together. Valve timing was set by eye while turning the engine over slowly watching when the valves opened and closed. A little more oil than the normal running level into the crankcase, some Colemans with a drip of 2-stroke oil into the fuel jar and give it a go. I got some pops straight away and with a bit more retardation of the timing it fired into life.

Throttle is by rotating the jam jar fuel tank but quite slow to react due to sizeable flywheel, advance & retard are a better way to set the speed which I had always intended was going to be for looks and noise rather than outright speed and performance.

Just goes to show that you don't need to worry about working to umpteen decimal places, a micrometer was only used on the crankshaft and the 0.8 MOD gears on metric ctrs were cut with 32DP cutter but it seems to start and run . Just needs a bit of colour to finish it offwink

Thread: Would you buy one of these collets?
12/10/2019 19:31:23

Does allow you to get a decent cutting speed if the machines spindle speed is limited, I got 500m/min cutting speed earlier todaysmiley

Thread: engine tightness
12/10/2019 19:26:42

Is your bore just the turned finish? honing will give a smoother bore with less initial friction but with still enough of a surface for the rings to bed into. A good oiling and running on air for a while will also help, just watch where the black oil coming out of the exhaust goes.

Thread: Would you buy one of these collets?
12/10/2019 17:12:15

If you also compare it to a standard R8 collet you will see that they grip in the tapered area but the oversize ones grip in the extended end so not as direct a closing force.

It's a bit like using a 5C step collet without the closing ring.

Edited By JasonB on 12/10/2019 17:14:31

12/10/2019 16:33:05
Posted by fizzy on 12/10/2019 15:57:31:

At not more than £10 from most well known UK suppliers why would you?

 

Fizzy it's an oversize one, question is will it hold

Edited By JasonB on 12/10/2019 17:12:42

Thread: Muncaster's Simple Entablature Engine
12/10/2019 13:47:56

Geoff, I don't recall doing anything special when it came to fitting the parts together. Making the cross head on the end of a bar helps as you can drill and tap it and then by doing the milling with a spin indexer it should ensure all the milling ops are equal either side of the piston rod hole. likewise making sure you accurately locate the ctr of the cylinder cover and then take equal amounts off either side will ensure the two guides sit equally either side of the piston rod.

On the guides I did each milling operation on one and then the other using a vice stop to ensure both parts went into the vice in the same position as they were swapped in and out. Once complete a slight tweak in the vice and checking against a straight edge was needed as there was a little distortion.

Then it is just a case of checking for free movement as each piece is assembled so you can tell what makes it go tight rather than building it all up and then trying to trace where a tight spot may be. Don't know if you have noticed but I also specified M2.5 for the fixing in the entablature but went with a 3.0mm hole in the top of the guide which gives a bit of wiggle room should it be needed.

J

Thread: diameter calculation
11/10/2019 18:25:20

I just looked in the Zeus book and took the figure for the distance between two holes in a three hole pattern and with a bit of simple maths got

1/0.86603 x 65 = 75.055

Every workshop should have one.

Thread: Electric Traction Engine
11/10/2019 17:47:55

I can, but they are a lot less work.

Thread: Is this chuck mounted on a 5C collet?
11/10/2019 16:29:35

R C Machines do 5C backplates and their "flying" wheels are quite good prices too which I know John Bogs bought several of.

Thread: Muncaster's Simple Entablature Engine
11/10/2019 16:19:07

The guides are indeed cut from solid.

This is basically as described in the text but photos will be a bit bigger:

First machine your two pieces of 6mm thick material to the overall 79.5mm x 20.0mm, then mark out so you can saw away most of the waste.

Now hold in the vice with the inner face resting on parallels and mill down the 6.2mm leaving 3mm which forms the horizontal leg.

Hold the part again with the inner face resting on a parallel but use a thicker one this time and mill the outerface for a length of 55.3mm from the bottom of the part and again leave 3mm thickness of material to form the vertical leg.

You can now blue the inner edge of the part and mark a line 23.5mm down which is just visible in the photo and I also carried a line around from that to show where the metal will be removed to but that is optional. Slip two matching diameter rods or drill bits onto the vice and use them to support the two internal corners machined in the earlier steps. This will hold the work at the correct angle so no measuring required, just machine down until the cutter is at the marked line on the side.

The final operation is to turn the part the other way up so the sloping face you just machined is resting on a parallel and mill out the remaining material to leave a 3mm finished thickness. No pic of that.

As for the cylinder that will indeed come out of 50mm stock as per the article, just offset the bore of teh cylinder, something like 4mm will do nicely and leave plenty to spare all round

muncaster cylinder stock.jpg

John, I'm also just about to send you a message so look at the green bar along the top of the page and your "inbox" will be flashing, click that.

11/10/2019 07:04:26

Welcome to the forum John, Are you having a go at making this one?

The two dimensions don't add up as one is to the internal corner and the other to the external as these are the extents of the two cuts I dimensioned it that way to give builders the sizes to cut. Will post a better detail later but this is the blown up drawing

mumcy guides.jpg

Thread: B & R Tite "Digger" Oscillating Engine
10/10/2019 19:23:53

It's not one I have knowingly seen before and does not come up when looking through an ME index

Thread: Warco wm18
10/10/2019 18:40:30

Some don't have the strut, the later ones do.

Thread: Solenoid Boxer 4
10/10/2019 16:37:11

I have embedded the video in Michael's post which shows the completed engine as the thumbnail.

Thread: Bright EN24T steel vs Black EN24T for cutting gears
10/10/2019 16:16:28

Possibly turned off for the video, the two blue pipes clipped to those fan spray outlets probably supply flood coolant in normal use and there is what looks like a coolant pipe at the far end of the hob

Thread: Victoria 7" flywheel on a 7x12 lathe?
10/10/2019 15:52:05

Working at max diameter you may well find the machine just stalls at 50rpm, different if you are running that speed and say threading M6 where the diameter is much smaller. That is why I advocate 3-400rpm and not too deep a cut. My 280 will happily do 10" flywheels at 300rpm but just comes to a stop if I take the same DOC at 50rpm, Brushless and inverter versions are better but may still be stalled.

Thread: Bright EN24T steel vs Black EN24T for cutting gears
10/10/2019 13:24:01

Ah I was thinking along the lines of HPC, Duval etc. I suppose a jobbing shop would use Involute cutters for a one off, would really depend on what equipment they have as it may be cheaper to sub it out.

As for hobbing a modern machine will drive the blank independantly by electronic means no need for gear trains so no need to run a particular way to get started unlike free hobbing and they seem to use climb cutting too. Though you probably won't find many bodging lodges with something like this.

10/10/2019 11:57:34

Adam, read my reply again, it is teeth ON THE CUTTER not the gear

10/10/2019 11:52:43

That seems quite a lot of teethquestion

I would have expected about 12, have you got a picture or link as teeth would be very thin

 

Edited By JasonB on 10/10/2019 11:54:39

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