BenHawkins Posted September 19, 2015 Author Share Posted September 19, 2015 Thanks for all the useful input on piston ring gaps. Looks like they are OK, so we are getting closer to putting the engine back together . I started the week by taking a piece of cast iron bar and turning the bore and OD to suit the gudgeon pin retaining groove. Then parting it off. Then it just needed deburring and splitting with a hacksaw and it was ready to fit to the piston. My next batch of laser cutting has arrived so I tacked a few of the bits together for the gear selector gate/handbrake arrangement, turned a boss and welded that on. There is still some work to get the exact arrangement sorted and the remaining parts laser cut. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted September 19, 2015 Author Share Posted September 19, 2015 The other part I made from the laser cut steel was the bonnet rest. The original drawing survives so that made the job fairly easy (although it was originally a casting). I started by tacking two profiles together. I had the flanges cut out along with one of the profiles (like an airfix kit). Then cut some of the strips off, cut them to length and tacked them on to the main profile. I left the bottom strip in place to prevent it from distorting as I fully welded it. Next job was to mark up the bulkhead for this and the side lamp brackets. After drilling I was able to try everything in place. That allowed me to measure up for the bonnet, another challenge for a later date. There will be no progress for the next week as work are sending me to a horrid part of India. Quote Link to comment Share on other sites More sharing options...
flandersflyer Posted September 21, 2015 Share Posted September 21, 2015 Thanks for all the useful input on piston ring gaps. Looks like they are OK, so we are getting closer to putting the engine back together . I started the week by taking a piece of cast iron bar and turning the bore and OD to suit the gudgeon pin retaining groove. Then parting it off. [ATTACH=CONFIG]108038[/ATTACH] Then it just needed deburring and splitting with a hacksaw and it was ready to fit to the piston. [ATTACH=CONFIG]108039[/ATTACH] My next batch of laser cutting has arrived so I tacked a few of the bits together for the gear selector gate/handbrake arrangement, turned a boss and welded that on. There is still some work to get the exact arrangement sorted and the remaining parts laser cut. [ATTACH=CONFIG]108040[/ATTACH] how was the original boss fitted? Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 4, 2015 Author Share Posted October 4, 2015 how was the original boss fitted? The whole lot was originally a casting but a lack of anything to copy, drawings or photos means I am fabricating it (in both sense of the word). I have been back from India for a week but managed to order some new thrust bearings and bronze for the king pins before leaving so they arrived whilst I was away. Severn Valley Railway finished riveting my front axle so I have been over to Bridgnorth to collect it. It has now had some paint. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 4, 2015 Author Share Posted October 4, 2015 The gear lever was set over further than the original could have been so I warmed it up and straightened it a little. The bore was also too big so I have made a reducing bush to take it down to 1". I milled a keyway in the selector shaft but have had to order some appropriate key steel. The spherical bush at the other end was missing the bronze sleeve so I turned one up and pressed it in. I have this operating lever from a different model but I think it is too long. I will have to wait to see if it can be adapted or if it is better to make another. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 4, 2015 Author Share Posted October 4, 2015 These number plate brackets are some of the few parts remaining from the last batch of laser cutting. The bend needed to be too close to the end for my v-block so I ended up abusing a drill vice to bend them. I bent these brake guides in the same way but using the v-block. These are listed in the parts book and visible in photos but I did not have drawings. They are made from the witness marks on the chassis and scaling off the photos. The surviving Dennis fire engine (a very similar chassis) do not show any signs of these guides; I assume they are to stop the rods vibrating and the shorter rods on the fire engines do not have that problem. I also welded a few more laser cut parts together to make these radiator brackets. I still need to make the clevises and tie rod to fix it to the dash. Finally I did a few more drawings for the laser cutters to quote on. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 11, 2015 Author Share Posted October 11, 2015 The first job of the week was to turn up a tube so I could press out the remaining king pin bushes. The wear is so bad on one of the king pins that is would not make sense to turn them down. Making the new king pins and bushes will keep me busy for quite a few evenings. I then started on the final laser cut profiles from the last batch. These were for the bonnet catches; thanks for Steve for supplying the sketch! The profiles cost just over a pound each and required centre drilling at each end so I could put them on the lathe to make them round. I used an angle grinder to blend the various shapes into each other. A die was used to put the thread on. The ends were heated and bent over using this jig. After sawing to length I finished them off with a file. Followed by a quick blast and coat of primer. I had other commitments this weekend but I did pay for another batch of laser cutting so I need to clear the workbench ready for the next set of tasks. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 18, 2015 Author Share Posted October 18, 2015 Here is a picture of the laser cut blanks for the bonnet catches before I started machining them. This shows the wear on the original king pins. So I started roughing some EN24T to size and drilled the grease hole with a very long drill. Still plenty of work to do before I have even one finished king pin. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 18, 2015 Author Share Posted October 18, 2015 The tie rod that secures the radiator back to the dash needs a clevis at each end. I cut four bits of 1" square steel to length (decided I would make them for the 1908 Dennis at the same time). Followed by scribing them up and cross drilling. Drilled a hole in the centre and tapped it 1/2BSF for the tie rod. Filed the radius on the end then milled the slot. And finally threaded them on a bolt and turned the diameter. Finally I gave them a coat of primer. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted October 18, 2015 Author Share Posted October 18, 2015 On Friday I collected another batch of laser cutting for a variety parts. Quite a bit of work associated with this lot. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 1, 2015 Author Share Posted November 1, 2015 Some of the laser cut parts were for making the bonnet louvre press tool. I filed the male part to shape as well as putting a small radius on the female edge. Then four bolts sort out the vertical alignment of the bonnet sides. I tried it out on a biscuit tin lid. The shape was right but the material was a little too flimsy resulting in crinkling. I was blindly confident this would not happen on the actual (and much thicker) bonnet I went to London yesterday to see the Regents Street motor show but on the way in popped in on the RCS Motor Club and borrowed their press as mine is slightly narrower than my bonnet sides. The first louvre was successful but the way I had made the tools each subsequent pressing got pushed over slightly by the radius on the prior louvre. By number three it was obvious I was too far out of alignment. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 1, 2015 Author Share Posted November 1, 2015 Working from the other end the tool worked perfectly. Unfortunately by this point the first bonnet side was scrap. So we proceeded with the other bonnet side. Which turned out well. Just need to get another blank laser cut out and repeat the process with the tooling assembled the other way round to make the opposite side. The other thing this week was to tack the selector gate parts together and try a first fit. It is nearly right but I can't quite get the lever over into the reverse position so it will require a little modification to the design. Quote Link to comment Share on other sites More sharing options...
Redherring Posted November 1, 2015 Share Posted November 1, 2015 For some time I have been wondering how to cut bonnet louvres. Can you tell us a few details. How thick was the bonnet material you used? Did you cut a slot first, if so, how was it done? Did you use oil? What are the traps for the novice? Great job... Robert Quote Link to comment Share on other sites More sharing options...
Asciidv Posted November 1, 2015 Share Posted November 1, 2015 Ben, What is the little cut present on some louvres and not on others. The louvres look absolutely super. It is interesting that it wasn't necessary to make the female part of the press tool to have the the same surface profile as the male part. Barry. P.S. I know you said your bonnet was painted but I have now found a company still with a tank of boiling cyanide/caustic soda/arsenic to do the original chemical blue'ing. My Big Four bonnet is now heading in that direction. Quote Link to comment Share on other sites More sharing options...
Old Bill Posted November 2, 2015 Share Posted November 2, 2015 [ATTACH=CONFIG]109366[/ATTACH] Judging by the shape of that press, you can tell it is in a student workshop! Only kidding! Lovely job Ben. Cutting the slot first is a brilliant idea. It is perfectly positioned and the tool doesn't need to cut the plate as well so it can be just a bit of mild steel as you have proven. Wish I had thought of that! Steve :-) Quote Link to comment Share on other sites More sharing options...
David Herbert Posted November 2, 2015 Share Posted November 2, 2015 Certainly cutting the slot first (easy with a lazer) makes it easy to position each louvre and gives it nice clean edges. The downside is that they have to be far enough from each other that each one doesn't pull the surrounding metal away from the louvre next to it. I think Ben has about the best compromise on that that he could get. Louvre tools usually cut the metal for the opening as part of the pressing operation which leaves a rather sharp edge and requires a great deal of force as it has to cut it all the way across at once instead of starting at one end as a guillotine does. Obviously the tool must be fully hard. However this means that if you work in the direction that Ben tried initially, the previous louvre is not affected by each subsequent one and the cut edges stay straight regardless of how close they are. I would guess that the little nick in the middle of the edge of each of Ben's louvres is the piercing hole made by the lazer before it actually cuts the slot. This would normally be in the waste part of say a hole being cut out but surely could have just been at one end of the cut that was wanted. It must be possible to program it out - assuming that it is not ment to be there ! David Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 3, 2015 Author Share Posted November 3, 2015 It looks like you guys have worked it all out whilst I was away! The original drawings state the bonnets were made from 18SWG planished steel so I went for 1.2mm CR4 steel. As you have worked out I had the slots cut by laser and the notches in the centre of each louvre are where the laser pierced the steel. I can't really see why they pierced them all in that position but I will ask if they can avoid it when I have another one cut. The only problem is these panels cost four pounds each and I need to reach a minimum order of 60 pounds. I either need to make 7 spare bonnets or draw some more parts up! This is the first time I have tried anything like this so I am no expert but I didn't use oil. I decided to have the slots cut as otherwise I would need a hardened tool and with the increased load required I would probably need a thicker piece of steel under the ram as well; not to mention that alignment of the parts of the tool would be critical. You will see there are four bolts keeping everything in line; these make sure the bonnet sides stay aligned as they slide through. I left a cut out in the top part of the tool so I could see the tool was lined up with the slot. Each slot was 1mm wide and I tried to line it up so I was half way across this slot each time. It was very helpful to have a glamorous assistant to hold the other end of the bonnet side. The bolt holes in the bottom two laser cut plates were made tight on the bolts but the top ones were slightly bigger and countersunk so they did not bind up on the bolts. Because the louvres are not on the centre line it all has to be assembled the other way round for the opposite side. The female part also has a (small) radius filed on it. This was also done by hand and is about a 1mm radius. I don't know for sure but I think a sharp edge might have cut the sheet steel instead of forming it. There are still many hours to go into the bonnet. The hinges are made from many strips of brass and there is a half round profile to be riveted all around the perimeter. Quote Link to comment Share on other sites More sharing options...
Redherring Posted November 4, 2015 Share Posted November 4, 2015 Fascinating... Please send photo of glamorous assistant...(NO! only joking) Quote Link to comment Share on other sites More sharing options...
David Herbert Posted November 4, 2015 Share Posted November 4, 2015 Is there any reasion for cutting slots 1mm wide ? I would have thought that just a single width cut piercing at one end and stopping at the other would have been simpler and been more like the original which would gave been cut by the louvre tool. Also you could try a smear of grease on only the male tool to reduce the metal that is pulled from the flat that is between adjacent louvres. You were right to put a small radius on the female part as there is a real risk of the material tearing there and it looks better in my view. They certainly look good though. David Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 4, 2015 Author Share Posted November 4, 2015 The 1mm slot was at the request of the laser cutters. I don't think they actually do any manual programming so it probably has to be a closed area for the software to pick it up or something like that. However that makes me more confused about how the extra notch got there! Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 8, 2015 Author Share Posted November 8, 2015 The perimeter of the bonnet is edged with 1/2"x1/4" convex brass. This was easy to purchase last time I wanted some but it seems that it is no longer manufactured in the UK. I spent some time phoning around and think I have found enough old stock to complete the job. I had to travel for work a couple of days this week and had family visiting for some the weekend so not the usual level of progress. However I did manage to pick up the new gear blank; turns out this had been finished for a while but they had failed to phone me and I had failed to chase them. In a cost saving exercise I have taken on the job of deburring and rounding the front of each tooth (this makes it easier to slide the gears into mesh). If I return the gear this week for hardening I should get it back soon. The box still needs quite a lot of work including new selector rods. In the spare minutes I have started shaping the laser cut profiles for the rear wing brackets. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 8, 2015 Author Share Posted November 8, 2015 The wing brackets need to look something like this. The plan is to weld a piece of round bar to the T shaped profiles and the rectangular flange that bolts to the chassis rail. I will have to estimate the bend required for the wings. I don't know if I will make the wings myself yet. It looks like it could be good fun but I think I need swaging rollers as they have a wired edge and a profile. Quote Link to comment Share on other sites More sharing options...
Asciidv Posted November 9, 2015 Share Posted November 9, 2015 (edited) Ben, what steel grade was the gear made out of? What process do they use to harden the teeth? It does look very nice! Edited November 10, 2015 by Asciidv Quote Link to comment Share on other sites More sharing options...
Asciidv Posted November 11, 2015 Share Posted November 11, 2015 The perimeter of the bonnet is edged with 1/2"x1/4" convex brass. This was easy to purchase last time I wanted some but it seems that it is no longer manufactured in the UK. Ben, This absolutely correct, with the only close manufacturer being in Germany. One of the largest brass stockists/distributors in this country is Holme Dodsworth http://holmedodsworth.com/ who are based in Newcastle Upon Tyne. Their stock is exhausted too, but I think Trish has persuaded them to re-order from Germany (Minimum delivery quantity 1 ton! - delivery 8 weeks), as we need some too for our bonnet projects. I will let you know what happens. Quote Link to comment Share on other sites More sharing options...
BenHawkins Posted November 15, 2015 Author Share Posted November 15, 2015 The gear was made from EN36. I will confirm what process they have used for hardening when I pick it up! This week has mostly been taken up by making bushes. I started by making on for the gear selector shaft. This one is pressed into a steel spherical ring that runs in a spherical housing to stop the bushes binding up on the shaft as the chassis twists. We went to the classic car show at the NEC on Friday and picked up a reasonably priced pair of Powell and Hanmer lamps. I had to file the lamp brackets down a little to make the fit. Quote Link to comment Share on other sites More sharing options...
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