CHUKY - Build One Yourself

[Gas_mantle]

Looking great Jason :-)

Could you show what that parting tool is in your posting 17/6/16 (when you cut the cylinder grooves), I still struggle sometimes with parting off and wonder if a tipped tool might be worth buying.

At the moment I've only ever used HSS and find I get mixed results :-(

[pgp001]

I reckon it will be one of this type. Best thing I ever did was start using these.



I have a spare blade if you want to have a go with it. You will have to make or buy a holder for it.

Phil

[Gas_mantle]

Thanks Phil,

I may well take you up on that, now that I've upgraded my lathe I'm looking at buying more tooling.

[Jasonb]

Mine is the Glanze version and I have got mine the right way up It takes the 2mm nominal width tips which does not put too much load onto the lathe.

https://www.chronos.ltd.uk/cgi-bin/sh000001.pl?WD=parting&PN=New_Glanze_Clamp_Type_Indexable_Parting_Tool_Starter_acks%2ehtml#a776130

Without getting into the parting off debate you should be able to do it with HSS as well.

[Gas_mantle]

Thanks Jason, I'd like to try something similar.

Great work on the engine 

[Jasonb]

Bearing Block

Drawing #8

Start by milling up a block of aluminium to the overall 16x22x17mm. Then hold in the mill vice with the top facing upwards and locate it centrally below the spindle followed by drilling the two M2.5 clearance holes.



Change to a 6mm dia cutter, touch off on the top of the block and then lower so you are taking a 3mm high cut, cut in 4.29mm from each side and while at that height bring the cutter in from each side to form the counterbore centrally over the stud holes.



Now holding the block on it side drill and then bore for the bearings aiming for a light press fit, if you over do it then a high temperature Loctite such as 648 can be used to retain the bearings. I opted to use number 686 unshielded bearings which are 6x13x3.5 from ARCEurotrade but 12mm OD ones would work just as well. As the flame can lick around the bearings avoid ones with rubber seals though if you have some to hand the seal can be flicked out with a pin or small jewlers screwdriver.



The last job is to round over the top, I did it by holding the work on a mandrel and then taking cuts at 5degree intervals on the spin indexer and then finished with a file. Could also be done on a rotary table or just by filing.



You can now fit the bearings, slip in the crankshaft and check all turns over nice and smoothly.



Included on the drawing are the 4 simple turned "washers" that fit into the counterbored holes in the sub base, once bonded in with JBWeld or similar they will look like cast.  bosses. Turn and drill sufficient material for the 4 parts and an allowance for parting cuts and then part them off and deburr.



J

[Jasonb]

Chimney

Drawing #9

The main chimney is a simple job from 10mm OD aluminium tube, thread one end M10x1.0 for a length of 22mm. Face to length and form the 9mm dia spigot on the other end. I used slightly larger OD tube so had to machine it down to overall diameter.



The base is just some 12mm stock drilled to 9.0mm and tapped M10x1.0 with the upper edge rounded off.

The top ring can be turned on the end of some bar and if you put a parting cut part way through so the bead can be easily shaped the drill will part off the work as it brakes through.



The parts can be assembled with a drop of Loctite 648 to hold the ring in place, make sure you have no more than 2mm of thread sticking out the bottom otherwise the exhaust passage in teh base will be restricted.



And a quick test fit to round off this installment.



J

[crueby]

Looking great!

 

[Jasonb]

Conrod

Drawing #10

This could be turned from a length of 10mm aluminium 6082 but I had a lot of 1/2" (12.7mm) so used that.

Cut off a piece about 20mm longer than needed, face each end and put in a small size 0 ctr drill hole, reduce one end to 8mm dia and the other to 10mm if using larger stock.



Now holding the rod in a mill vice the two holes can be drilled and reamed and the ends flattened off.



Back to the lathe hold the 10mm end in a collet or 3-jaw and offset the tailstock to form the taper, I used a small live ctr in a boring head to get the offset rather than disturb the setting. You could also set the topslide to an angle if prefered. Do the final cut swith either a small HSS tool with a rounded end or an insert tool like I used in the photo to give the fillet where the round rod joins the flat ends. Do take it easy as the rod is getting quite thin at this stage but will be nice and light.



The two bearings are simple turning jobs from a bit of bronze bar with reamed holes. I find the mill vice is quite good for pressing them in, use a spacer on the big end so the bearing can protrude evenly both sides. If your fit is a bit loose then high temp Loctite such as 648 should hold the bearings in place.



This is the finished rod together with the Gudgeon pin block and piston described earlier



That's another bit off the list, hopefully you won't have to wait so long for the next installment

J

[yogi]

Looking good Jason! 
I'm glad to see an update on this engine. Looking forward to the next installment. 

[Gas_mantle]

Great to see an update Jason 

I'm interested in the set up you have to cut the taper using a boring head as the offset as I want to do something similar for the Muncaster columns, is it a homemade live centre to fit the head ? I was planning on just making a temporary dead centre out of steel to fit 

[Jasonb]

Thanks Guys

Peter I know you have the photos for the Muncaster which show me doing the same thing but not easy to follow without my build description. I used the ctr from my old Unimat3 but a solid one would do and there are reasonably priced far eastern versions of the Emco one about.

[Gas_mantle]

Thanks, I didn't realise it was possible to buy small live centres with a parallel shank but it looks like this is the kind of thing I need 

https://www.rdgtools.co.uk/acatalog/Revolving--Center-for-Taper-Turning-Long-Tapers-1272.html

[Jasonb]

Shutter parts

Drawing #11

Shutter Rod Guide

I did not have any 5mm thick brass so thinned down the end of a piece of 1/4" material and then drilled the 2.0mm hole at least 31mm deep.



With the work now on it's side the recess was milled out with a 6.0mm cutter to give the required 3.0mm radius to the internal corners.



After cutting off from the parent bar the back face is milled to finished size and then the 1.0mm step cut from the lower end.



Turning the part the other way up the larger recess can be milled out, the two 2.0mm holes drilled and then countersunk then finish off by filing the 2.5mm radius around the upper screw hole.




Shutter

This starts life as a Stanley knife blade or "utility" knife as I think our American members call them. It is best to shape the knife blade after the steel block has been soldered on just in case it moves about during silver soldering. Also worth leaving te block a bit long to start with so just make teh 5x8 dims to finished size then solder.



The blade can then be roughly trimmed to size making sure the edges are true to the edges of the block. With the rod guide screwed into place machine a point onto some 2.0mm rod and pass that through the guide and use the rod as a scriber to mark the position of the M2 hole.





The hole can now be drilled and then tapped M2 and the block rounded over. I would suggest leaving the final shaping of the shutter until it is mounted on it's rod.

Shutter Rod

This is quite a simple job so no photos, face the rod to length and cut the M2 thread on each end to the lengths required.

This shot shows the finished part , the fork and cam follower roller will be covered next time.



J

[Jasonb]

Cam Follower and Valve

Drawing #12

Cam Follower

A simple turning job from brass, face off, drill 2.0mm and part off to 2.0mm thick

Cam Follower Fork

I did not have any 5mm square stock so milled down the end of a round bar and while in the indexer drilled and countersunk the 2.0mm hole then rotated it 90degrees and used a slitting saw to form the slot. Then into the lathe to drill 1.6mm and tap M2 before parting off to length.

Cam Follower pin

Another simple turning job, make sure the head is small enough to fit just below the surface of the Follower Fork.

You will also need a small dia spring to slip over the valve rod, about 20mm free length, 0.5mm wire. Does not need to be too strong as that will increase the load on the engine - just enough to keep the follower in contact with the cam


Valve

Face off the end of a piece of cast iron , turn OD down to 28.0mm and then part off a 0.5mm thick slice, if your parting tool leaves a pip in the middle don't remove it.



The eight sides that form the octagon can just be filed but make sure you leave a small part of the 28.0mm dia edge between each as it will help keep the valve centred within the base. The valve can then be lapped on some 1200g wet & dry using a disc of metal to keep it flat, this is where the pip helps.



Parting off will leave the valve slightly concave so you only need to lap the edge as can be seen by the polished area



J