Author Topic: 15cc Seal and 30cc Seal Major  (Read 9962 times)

Online b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13595
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: 15cc Seal and 30cc Seal Major
« Reply #120 on: July 12, 2019, 01:48:22 PM »
Glad to know that the cylinder insertion tool worked well for the most part. That is one task you are probably happy to have behind you now.

Bill

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6532
  • Surrey, UK
Re: 15cc Seal and 30cc Seal Major
« Reply #121 on: July 12, 2019, 03:11:32 PM »


That's more or less I have found. I had hoped you would have a method to reliably trepan a couple of inches deep from both ends of a CI bar.

Anyone else have any good ideas?

A bit long winded but you can use a cranked tool to undercut each ring and then part off which leaves the core intact, probably a task for a rear mounted parting tool and the cranked tool in the main toolpost. As the undercut is shallow you don't get a problem of swarf buildup like you would if doing a long length in one go



If you really want to see how it's done have a look at some of this guys videos.


And how to make the cutter

« Last Edit: July 12, 2019, 03:15:14 PM by Jasonb »

Online Vixen

  • Full Member
  • ****
  • Posts: 1225
  • Hampshire UK
Re: 15cc Seal and 30cc Seal Major
« Reply #122 on: July 12, 2019, 05:22:43 PM »
Yup, that's the way to do it.

Mike
It is the journey that matters, not the destination

Offline Johnmcc69

  • Full Member
  • ****
  • Posts: 480
  • Erie Pa., USA
Re: 15cc Seal and 30cc Seal Major
« Reply #123 on: July 12, 2019, 06:57:33 PM »
Now that's some pretty amazing tool making there!

 Just...WOW!!!

 John

Online Laurentic

  • Full Member
  • ****
  • Posts: 60
  • Nr Yeovil, England
Re: 15cc Seal and 30cc Seal Major
« Reply #124 on: July 12, 2019, 07:11:05 PM »

But I still broke a ring  :toilet_claw:

Jo
That's why you need copious amounts of lub oil - dry and they all would have broke I suspect. !!  Fragile animals, piston rings.
Glad it worked

Chris

Online Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 3952
  • Switzerland
Re: 15cc Seal and 30cc Seal Major
« Reply #125 on: July 12, 2019, 07:47:21 PM »
Hi Mike, I have tried using various tools but things like hole saws will not let you get very deep. I have a number of specially shaped HSS tools but loose about 10mm on the diameter if I use those 
Jo

That's more or less I have found. I had hoped you would have a method to reliably trepan a couple of inches deep from both ends of a CI bar.

Anyone else have any good ideas?

Cheers

Mike

I have had success with some Bosch hole saws in cast iron and aluminium. This may be because my bench drill is the most powerful machine I have. The hole saws are 40mm deep and the pieces I was working on were 78mm long.
« Last Edit: July 13, 2019, 12:48:54 PM by Roger B »
Best regards

Roger

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12548
  • Hampshire, england.
Re: 15cc Seal and 30cc Seal Major
« Reply #126 on: July 15, 2019, 07:21:17 PM »
Following on from the postman delivering the big ends screws for the Seal (Thank you Dave   :) ) each of the rods have been drilled and tapped.

The trick to position the rods in the vice for drilling the bolt holes is to use the centre line of the rod to get it square in a vice then to  balance out the spacing of the bolts to get the same amount of metal around both bolts.


The next trick is to position the slit in the rod so that it is at the right distance from the centre of the small end boss  :thinking:

Jo
Usus est optimum magister

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12548
  • Hampshire, england.
Re: 15cc Seal and 30cc Seal Major
« Reply #127 on: July 16, 2019, 06:29:17 PM »
My supplier. having first sold me the connecting rod castings for the Seal, said "ho I wouldn't bother with them I'd use barstock"   ::)

Starting with the Major's rods the small end is pinned to the jig so that the middle of the small end is under the spindle and then clamped in place. It can then be drilled and reamed. Looking at the positioning of the hole it is not central on either side of the rod but is a balance between the two. I have four usable Major rods ready for the next phase.

However  :Mad: having drilled and reamed the Seal's ones bits started coming away from the castings leaving holes  :toilet_claw: So I will be making the Seal rods out of Bar Stock  :facepalm: maybe tomorrow

Jo
Usus est optimum magister

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 471
  • Raleigh,NC. USA
    • Lauson small engines
Re: 15cc Seal and 30cc Seal Major
« Reply #128 on: July 17, 2019, 08:23:32 PM »
My supplier. having first sold me the connecting rod castings for the Seal, said "ho I wouldn't bother with them I'd use barstock"   ::)

Jo

Well, you can't say he didn't tell you  :LittleDevil:

And... I machined the water pump casting on the Frisco only to find the casting was porous, with water squirting out all over the place.  Fortunately a little gas tank sealant corrected that problem but... I feel your pain.  Bar stock it is.
Craig

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12548
  • Hampshire, england.
Re: 15cc Seal and 30cc Seal Major
« Reply #129 on: July 18, 2019, 01:29:07 PM »
Thank you Craig   ::) he waited over 12 months after he took my money for the rods before he told me    :slap:


The replacement con rods are going to be made out of some ex fast jet scrap-binium. This is not HE15 but much stronger and machines like BMS and has good bearing properties  :ThumbsUp:

First up machine the Ali to a 20mm wide and 9.5mm thick and start thinking about the measurements  :thinking: I am going to change the spacing of the big end bolts as originally there was only 0.3mm between the bolts and the bearing surface on either side, so the 11.1mm has been increased to 11.7mm.

The machining operations for bar stock is different from a casting as first the bottom end is machined flat, has the two holes drilled and tapped for the M2.5mm thread before using a slitting saw to cut the cap off the rod.  The small end hole has at this stage not been done  :hellno:

Three more for the set...

Jo

P.S. I was told the scrap-binium was good for Mach 3 which is a little faster than I intend on running this engine  ;)
« Last Edit: July 18, 2019, 05:14:15 PM by Jo »
Usus est optimum magister

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6532
  • Surrey, UK
Re: 15cc Seal and 30cc Seal Major
« Reply #130 on: July 18, 2019, 04:14:20 PM »

P.S. I was told the scrap-binium was good for Mach 3 which is a little faster than I intend on running this engine  ;)

Good for CNC work then ;)

Online Vixen

  • Full Member
  • ****
  • Posts: 1225
  • Hampshire UK
Re: 15cc Seal and 30cc Seal Major
« Reply #131 on: July 18, 2019, 07:41:04 PM »
. I was told the scrap-binium was good for Mach 3 which is a little faster than I intend on running this engine  ;)

Good decision Jo;

Conrods made from aircraft grade scrap-binium bar stock have got to be better than aero (chocolate bar) grade castings. Better still; go out and buy the correct grade of bar stock from a reputable metal stockist.

Cheers

Mike
It is the journey that matters, not the destination

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12548
  • Hampshire, england.
Re: 15cc Seal and 30cc Seal Major
« Reply #132 on: July 18, 2019, 08:08:45 PM »
Better still; go out and buy the correct grade of bar stock from a reputable metal stockist.

Strange you should mention that I recall on at least three occasions we made fast-jet airframes out of fully certificated metal from a reputable metal stockist only to find that when we did our own metallurgical analysis of it it was not what they claimed it was. The supply of the metal was finally traced back to a far Eastern smelter  >:( . All three aircraft with the offending metal had to be stripped down again and the frames scrapped  :disappointed:


The drawings say bronze which is rather heavier than the supplied Ali castings. What I am using is the same stuff I make my conrods out of for my single cylinder model aero engines  :ThumbsUp:

Jo

 
Usus est optimum magister

Offline gadabout

  • Full Member
  • ****
  • Posts: 35
Re: 15cc Seal and 30cc Seal Major
« Reply #133 on: July 23, 2019, 08:38:58 AM »
Jo,
I just did a test assembly of my Seal with Pistons on the rods and crank in and found the rods foul the cylinder liner on one side !!! Looks like I will have to notch the liners on one side :'( . Clears the other side due to the offset bores. Wonder if others have found the same issue. Also had to reduce the rod widths slightly to get them down the bores. Just noticed on the plans that the pistons are shown as flush with the top of the block but if you add up all the dimensions the Pistons sit .03125" above the top and that is where mine are but the head doesn't go on now and will need relieving more .....
Mark
« Last Edit: July 23, 2019, 10:03:46 AM by gadabout »

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 12548
  • Hampshire, england.
Re: 15cc Seal and 30cc Seal Major
« Reply #134 on: July 23, 2019, 10:28:41 AM »
I agree with your dimensions Mark.

The cylinder head for my Seal has not yet had the underside milled out and is only 0.6mm deep the drawings show it needs to be 0.8mm, 1mm might be safer.

I have just checked the Major and the pistons will stick up 0.81mm but the counter bore is 1.2mm into the head  :)

Jo
« Last Edit: July 23, 2019, 10:32:54 AM by Jo »
Usus est optimum magister