The Workshop Progress Thread (2016)

[Neil WyattModerator @neilwyatt]

Posted by Chris Evans 6 on 14/04/2016 08:59:46:

Neil, I am going to make one of those knurling devises. What size knurl wheels did you use ?

I think they are 3/4" with 3/16 holes and 5/8" wide, but that's without digging them out and measuring.

Personally i would source knurls first THEN make the device.

If I made it again it would be a bit bigger and a bit more robust, but most designs are greatly over-engineered as the knurls will self-align to a great extent and the force required is NOT as huge as legend suggests, even in steel.

Main feature to note are bronze pins and washers for the knurls.

Neil

[Nick WheelerParticipant @nickwheeler]

Posted by duncan webster on 15/04/2016 14:15:13:

A good source of air receivers for your compressor is a lorry scrap yard. If you want bigger just use more in parallel. Make sure you fit a drain and remember to let out the water every now and again.

Which never happens when they are fitted to lorries. And is why they are often replaced due to corrosion.

[michael darbyParticipant @michaeldarby61557]

Most commercial vehicles have automatic drain valves now operate on a timer after the ignition is off and handbrake applied.

[MuzzerParticipant @muzzer]

If you are ever standing next to a lorry and there's a sudden release of compressed air (apart from the brakes being released by the driver), it's likely to be the purge valve. It's the device that collects condensate (water) automatically and dumps it when it reaches a certain level. It's triggered by the back pressure ie not timed but happens when the cannister is full.

Nowadays there tends to be a silencer on the exhaust so that nearby pedestrians don't sympathetically empty themselves due to the unexpected and sudden noise.

[davebParticipant @daveb17630]

Some of us older pedestrians have a similar mechanism but without the silencer.

[Nick HughesParticipant @nickhughes97026]

Posted by daveb on 16/04/2016 11:57:14:

Some of us older pedestrians have a similar mechanism but without the silencer.

Not me, Flatulance Ninja, silent and deadly!

[JAParticipant @ja]

Posted by Nick Hughes on 16/04/2016 13:18:59:

Posted by daveb on 16/04/2016 11:57:14:

Some of us older pedestrians have a similar mechanism but without the silencer.

Not me, Flatulance Ninja, silent and deadly!

Dodgy emissions data next?

JA

[Anonymous]

I've finally done the last of the machining on my re-designed Burrell water pumps, the spigot with an external thread roughly in the centre of this picture:

It's the first time I've used slow helix drills on gunmetal. They seem to work pretty well with no snatching, so I will be buying a few more useful sizes. All the other threads have been screwcut on the lathe but one of the mounting spigots being in the way makes this difficult in this case without a special insert toolholder. So I bodged a special thin holder for the 3/8" BSP die instead:

There are still a few bits left to do on the water pumps, but it's now full steam ahead on the wheels.

Andrew

[JasonBModerator @jasonb]

Looks good Andrew, would that have been a candidate for thread milling?

Over the last couple of weeks I have continued to remove metal from the lightweights crankcase on the mill followed by a good going over with the Dremel and am just about there, I gave it a coat of etch primer last night as that shows up any areas that still need a bit of attension.

Anyone care to take a guess at the finished weight of just the crankcase, I started off with a block of 6082 that weighed just a shade under 1.5kg.

I have also got some work done on the crankshaft, cut from 2" EN8. Bit of a long tool overhang to reach the pin and the gap between the webs is only 7/16"

[MuzzerParticipant @muzzer]

How did you machine it? A (very long) series of manual operations with lathes and rotary tables etc or have you got CNC control? Looking good, mind….

[JasonBModerator @jasonb]

All manual, as you say on the lathe and a lot of rotary table work. I'll do a build thread in due coarse with an explanation of what I'm upto but these will give an idea.

This is one of the cast magnesium originals that I am trying to replicate.

[Ian S CParticipant @iansc]

Jason, reckon your 1.5Kg is down toward .25 Kg, I suppose that's why some are casting fans. Looking good.

Ian S C

[Anonymous]

Jason: Looking good, that's a lot of machining though! I expect to see the engine running at the next SCMTEG steam up.

I could have thread milled the BSP thread, but I would have had to obtain a 55º thread mill, whereas I already had the BSP die. And I would have been reluctant to use the water pump casting as a trial for thread milling; there's a lot of time invested in it!

Andrew

[JasonBModerator @jasonb]

You are a bit high Ian.

Should hopefully be done by October maybe even ready for Guildford in July.

[Bob RodgersonParticipant @bobrodgerson97362]

Jason,

here's one I did earlier.Its a drive side Crank Case half for a 1905 Rover Forecar. If memory serves me well it was 16" across from hanger to Hanger. I also made a new crankshaft for it.

The Block of HE 30was 18" X 4" X 12" or thereabouts. A great deal of effort and time was saved by getting the outer profile water jet cut. Here is the billet with the embryonic crank case half inside it after jet cutting.

Into the lathe first of all.

Further lathe work

Onto the Manual Milling Table

Lots of cuttings were generated in the mill.

Almost finished profiling in the mill and a little work with the Dremel to blend in some of the radii etc.

Using the Timing side half as a template to machine the mounting lugs.

Further work Carries on

Finished with the Dremel Prior to grit blasting.

A Trial fit in the scrap left over from jet blasting.

The bottom end of the engine together

On The Road at last on a cold February morning.

[JasonBModerator @jasonb]

Thanks Bob, as Ian said itcan be a lot of machining but thats what I enjoy. If I had paid a high price I could have got castings for this engine as there are a few about but there is not much to challenge me there, the crankcase would just need two surfaces facing, a few large holes bored and some smaller ones tapped. Opting to cut from solid gives me a lot more to think about and is far more satisfying plus I get a lot more workshop time for a much lower outlay as the block of 6082 was far less than a casting.

J

[Neil WyattModerator @neilwyatt]

The thing this forum is missing is a 'like' button

Neil

[Bob RodgersonParticipant @bobrodgerson97362]

Hi Jason,

it's a nice way to make things but you really have to concentrate on what you are doing. In the past I have specialised in making replacement casings for veteran and vintage motorcycles and have found that virtually all of the really early engines suffered badly from casting porosity. I suppose at the turn of the 20th century they were just learning how to alloy the metal and perfecting casting techniques.

By making replacements in alloy billet you get a much stronger component than the original.

Bob

[HopperParticipant @hopper]

I thought I had done rather well getting the machining done on my fabricated GHT Versatile Dividing Head, until I looked at Bob's epic crankcase machining above. Wow, just wow!

Ready for some filler in those spoggy holes and a lick of paint and it should look like a bought 'un.

Edited By Hopper on 23/04/2016 05:45:22

[martin perman 1Participant @martinperman1]

Andrew and Jason,

You both must have clocks with display more than 24 hrs a day, what with working for a living, 13hr days currently, and doing job for my Daughter and son in law and looking after my wife I havent got enough hours on my clocks, excellent work from both of you, I like reading what you both produce.

Martin P

[Ian S CParticipant @iansc]

Jason, I actually put 200gm to start with, but changed it up before posting.

Ian S C

[JasonBModerator @jasonb]

Closer but still a little high.

[JasonBModerator @jasonb]

Got the main bits of the crankshaft finished so decided to make and fit the bronze bearings. As this is a two stroke you don't want the crankcase leaking air so a reasonable fit on the bearings is needed, think these will be OK once there is a bit of oil on them. All seems to turn over nice and freely and there is about 0.001" endfloat.

A DCGT ALU AK10 tip gave the best finish on the EN8 crankshaft.

Edited By JasonB on 23/04/2016 20:36:58

[Ian S CParticipant @iansc]

That's my answer, see if someone else can get it. I often have scales handy to weigh parts for my hot air motors, it's amazing the amount of metal that goes out in the rubbish at times.

Ian S C

[Anonymous]

Posted by martin perman on 23/04/2016 06:49:46:

Andrew and Jason,

You both must have clocks with display more than 24 hrs a day, what with working for a living, 13hr days currently, and doing job for my Daughter and son in law and looking after my wife I havent got enough hours on my clocks, excellent work from both of you, I like reading what you both produce.

Thanks Martin; it takes me time and effort to post and it is useful to know that at least they're being read!

Andrew

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