By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Dec 6th

3 cyl Pip engine

All Topics | Latest Posts

Search for:  in Thread Title in  
David Kenyon 222/12/2018 14:47:14
207 forum posts
151 photos

I also need two centres through the crank pin axes for machining the big end.
To do this the bar is fitted to two 'V' blocks and clamped in my mill vice on the mill.
I centred the mill spindle over the first centre drill and then moved the mill table
over to the crank pin axes and put a second centre drill. The bar was flipped 180 degrees
while still clamped to the 'V' blocks and the process was repeated.

David Kenyon 222/12/2018 14:48:13
207 forum posts
151 photos

Now I have the centres I mounted the bar first between the mains and then the crankpin to remove
the bulk material. p1030687 (medium).jpg

David Kenyon 222/12/2018 14:51:28
207 forum posts
151 photos

Then more material is removed to form the basic shape

As I get down to the final sizes lighter and lighter cuts are used to try and get a nice finish.p1030689 (medium).jpg

David Kenyon 222/12/2018 14:52:44
207 forum posts
151 photos

Back on the mill table I need to cut a 20t 48dp gear on the crank to drive the planet gears
I made earlier. I could not use the gear cutter I used on the planet gears as the gear is cut
close to the crank web and needed to be a smaller diameter cutter. So I made cutter from
silver steel , there is plenty of info about making gear cutters on the internet so I won't describe
it here.p1030695 (medium).jpg

David Kenyon 222/12/2018 14:53:45
207 forum posts
151 photos

With the gear cut I used a milling cutter to form the crank web p1030696 (medium).jpg

David Kenyon 228/12/2018 20:37:35
207 forum posts
151 photos

The crank needs extra weight to balance the engine so I turned and milled a counterweight
out of mild steel.p1030751 (medium).jpg

David Kenyon 228/12/2018 20:38:23
207 forum posts
151 photos

Then it is pinned in placep1030752 (medium).jpg

David Kenyon 228/12/2018 20:39:34
207 forum posts
151 photos

Once pinned I silver soldered it in placep1030826 (medium).jpg

David Kenyon 228/12/2018 20:42:31
207 forum posts
151 photos

Camshaft, the camshaft is made from 1.25'' silver steel round bar.
First I turned a piece down to size and then turned a small shoulder on the front.

David Kenyon 228/12/2018 20:43:22
207 forum posts
151 photos

The centre is then drilled and reamed ready to accept a bronze bush. Using a
parting blade I made a thin groove which is used to separate the inlet lobe
from the exhaust lobe then parted the piece off.p1030816 (medium).jpg

David Kenyon 228/12/2018 20:43:58
207 forum posts
151 photos

With the piece mounted on the mill I drilled and reamed the two holes which the planet gears
will run in. These holes were drilled through into the mounting block so I could fit two
pegs in to help locate the piece.

David Kenyon 228/12/2018 20:49:13
207 forum posts
151 photos

Next job was to mill the sides away to form the inlet lobes , only milling down to the grove used to
separate the lobes. Then the piece was flipped over and the exhaust lobes were milled in the same way. p1030822 (medium).jpg

David Kenyon 228/12/2018 20:50:05
207 forum posts
151 photos

The piece is then heat treated to harden the silver steel p1030832 (medium).jpg

David Kenyon 228/12/2018 20:51:19
207 forum posts
151 photos

Made some bronze bushes and pressed them into the Cam p1030852 (medium).jpg

David Kenyon 228/12/2018 20:53:21
207 forum posts
151 photos

All the items for the cam drivep1030930 (medium).jpg

David Kenyon 228/12/2018 20:53:53
207 forum posts
151 photos

p1030931 (medium).jpg

David Kenyon 228/12/2018 20:54:55
207 forum posts
151 photos

I made the big end bearing from phosphor bronze, the bearing is threaded into
the master con rod to help with assemblyp1030933 (medium).jpg

David Kenyon 228/12/2018 20:56:01
207 forum posts
151 photos

Then I started the con rod, this is made from 6061t alloy which has a greater mechanical strength than
the 6080 I have used for the crankcase.

David Kenyon 228/12/2018 20:56:51
207 forum posts
151 photos

p1030935 (medium).jpg
So I mounted a piece of alloy on the mill centred over the big end , I used a scrap piece of alloy underneath
to save damaging my rotary table.
I centre drilled ,drilled and tapped m10 fine through for the big end bearing then moved the table and
drilled , tapped m4 the holes for the slave rod pins.

David Kenyon 228/12/2018 20:57:57
207 forum posts
151 photos

The slave rod holes were then opened out to 6mm for half the depth of the rod. The big end bearing is screwed
into the rod by hand, I machined a slot and tightened with a screw driver then using an m6 end mill I relived the
bearing were it covered the slave rod holesp1030937 (medium).jpg

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric Engineering
Allendale Electronics
Eccentric July 5 2018
Tee London LMES 6th Dec
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest