chrisveitch Posted April 18, 2018 Share Posted April 18, 2018 I'm building an Association replacement Pannier chassis and have a persistent problem with the frames bending slightly when soldering in the spacers. I've tried redoing them a couple of times and always get the same (or similar) result - I check the spacer sizes are correct, frames are straight etc. but after the last spacer is soldered in they come out of the jig bent to one side at one end. I've got it down to about a 0.4mm bend along the length of the chassis, but it's not right and I don't know what I'm doing wrong. Is it just me, or is this a common phenomenon with expansion/contraction of the frames or something similar? Regards, Chris Link to post Share on other sites More sharing options...
richbrummitt Posted April 18, 2018 Share Posted April 18, 2018 Are you using horizontal and vertical spacers? A picture (or more) would aid our understanding and help with feedback. Link to post Share on other sites More sharing options...
chrisveitch Posted April 18, 2018 Share Posted April 18, 2018 Are you using horizontal and vertical spacers? A picture (or more) would aid our understanding and help with feedback. Sorry, don’t have a photo to hand but will try for one when next in the workshop. I’m using horizontal PCB spacers milled to fit in the pockets provided in the chassis kit, and assembling it in the jig provided. The frames seem to be OK in the vertical but pull away to one side in the horizontal towards the rear of the chassis (which is where the last spacer was soldered in). Link to post Share on other sites More sharing options...
Chris Higgs Posted April 19, 2018 Share Posted April 19, 2018 Sorry, don’t have a photo to hand but will try for one when next in the workshop. I’m using horizontal PCB spacers milled to fit in the pockets provided in the chassis kit, and assembling it in the jig provided. The frames seem to be OK in the vertical but pull away to one side in the horizontal towards the rear of the chassis (which is where the last spacer was soldered in). I can only think there are hidden stresses in the frames which show up when soldered. I checked the artwork again and there is no issues with the jig. So try assembling it upside down in the jig (this was designed to be possible), soldering the spacers in a different order and so on. When all else fails you could put a slight bow in the frames in the opposite direction to the probam you have but you will have to be careful not to distort them. Chris Link to post Share on other sites More sharing options...
Roger.s Posted April 19, 2018 Share Posted April 19, 2018 Emphatically, a decent vice is required. Quite expensive, but worth every penny. http://www.cooksongold.com/Jewellery-Tools/Precision-Bench-Vice-prcode-997-1080 I could not produce my engines without a similar version. Tim How does the "bench plate" fix to the bench? Does it need to have a recess cut in the bench or is it a clamp on device. I need one to fix to the kitchen table without upsetting anyone. Link to post Share on other sites More sharing options...
RMweb Gold queensquare Posted April 19, 2018 RMweb Gold Share Posted April 19, 2018 How does the "bench plate" fix to the bench? Does it need to have a recess cut in the bench or is it a clamp on device. I need one to fix to the kitchen table without upsetting anyone. Fully agree with Tim, a good vice and a selection of descent quality files are crucial. The base plate screws down. I have an extra baseplate on my portable workbench which I take to shows or when I want to work in the house as opposed to the workshop - an ideal solution if you are going to be based at the kitchen table. A piece of cheap camping mat rubber underneath will stop it slipping or marking Jerry 3 Link to post Share on other sites More sharing options...
chrisveitch Posted April 19, 2018 Share Posted April 19, 2018 I can only think there are hidden stresses in the frames which show up when soldered. I checked the artwork again and there is no issues with the jig. So try assembling it upside down in the jig (this was designed to be possible), soldering the spacers in a different order and so on. When all else fails you could put a slight bow in the frames in the opposite direction to the probam you have but you will have to be careful not to distort them. Chris Thanks Chris - I'm confident it's not the jig and is definitely something to do with my cack-handed assembly. I'm wondering if it's something I've done with the centre spacer, which is the one I've never removed and replaced so it could definitely be a problem with the order of assembly. I'll try your suggestions and see how I get on... Link to post Share on other sites More sharing options...
RMweb Premium nick_bastable Posted April 19, 2018 RMweb Premium Share Posted April 19, 2018 Sorry, don’t have a photo to hand but will try for one when next in the workshop. I’m using horizontal PCB spacers milled to fit in the pockets provided in the chassis kit, and assembling it in the jig provided. The frames seem to be OK in the vertical but pull away to one side in the horizontal towards the rear of the chassis (which is where the last spacer was soldered in). can you confirm you have added vertical spacers please Nick Link to post Share on other sites More sharing options...
Mr chapman Posted April 19, 2018 Share Posted April 19, 2018 Thanks for the tip on the little vice. I have a small vice but I could really do with a smooth jawed version. That and some diddy reamers! Has anyone got a picture of how the vacuum cylinder fits on the sample kit? Appears to sit at a slight angle as it doesn't want to sit flat. Hence the fold line I'm guessing. The instructions aren't too clear on that, just says attach it It's going together well though! Nice design I must say Link to post Share on other sites More sharing options...
chrisveitch Posted April 19, 2018 Share Posted April 19, 2018 can you confirm you have added vertical spacers please Nick No, just 3 horizontal spacers as shown in the drawing on the instruction sheet PDF document. Link to post Share on other sites More sharing options...
Roger.s Posted April 19, 2018 Share Posted April 19, 2018 Fully agree with Tim, a good vice and a selection of descent quality files are crucial. The base plate screws down. I have an extra baseplate on my portable workbench which I take to shows or when I want to work in the house as opposed to the workshop - an ideal solution if you are going to be based at the kitchen table. A piece of cheap camping mat rubber underneath will stop it slipping or marking IMG_3918.JPG IMG_3919.JPG Jerry Thanks Jerry ~ just what I wanted to know! I wonder if Edward Sissling stocks them. Roger 1 Link to post Share on other sites More sharing options...
RMweb Premium nick_bastable Posted April 19, 2018 RMweb Premium Share Posted April 19, 2018 (edited) No, just 3 horizontal spacers as shown in the drawing on the instruction sheet PDF document. I have just checked the sketch and you have followed the instructions, however most other chassis have down vertical supports see the 03/04 or 4f etc I think this may resolve your problem keep trying it took me many years to make a working (if still unfinished) chassis Nick Edited April 19, 2018 by nick_bastable Link to post Share on other sites More sharing options...
RMweb Premium Ian Morgan Posted April 20, 2018 RMweb Premium Share Posted April 20, 2018 It took me nearly 30 years to make the first working chassis I was pleased with. It took a couple of months to make the second one. Lots of lessons learned. 1 Link to post Share on other sites More sharing options...
Chris Higgs Posted April 20, 2018 Share Posted April 20, 2018 (edited) I have just checked the sketch and you have followed the instructions, however most other chassis have down vertical supports see the 03/04 or 4f etc I think this may resolve your problem keep trying it took me many years to make a working (if still unfinished) chassis Nick I am not sure whether vertical spacers will help with the chassis bowing in the horizontal direction. But there is certainly potential with this chassis to make both the central and rear spacers longer if you prefer. That should make it less flexible. Edited April 20, 2018 by Chris Higgs Link to post Share on other sites More sharing options...
chrisveitch Posted April 20, 2018 Share Posted April 20, 2018 I am not sure whether vertical spacers will help with the chassis bowing in the horizontal direction. But there is certainly potential with this chassis to make both the central and rear spacers longer if you prefer. That should make it less flexible. Thanks Chris - to be honest I’d not thought of that but it does sound worth a try, although I’m still sure it’s my technique that’s somehow at fault. Link to post Share on other sites More sharing options...
Mim Posted April 20, 2018 Share Posted April 20, 2018 I'm building an Association replacement Pannier chassis and have a persistent problem with the frames bending slightly when soldering in the spacers. I've tried redoing them a couple of times and always get the same (or similar) result - I check the spacer sizes are correct, frames are straight etc. but after the last spacer is soldered in they come out of the jig bent to one side at one end. I've got it down to about a 0.4mm bend along the length of the chassis, but it's not right and I don't know what I'm doing wrong. Is it just me, or is this a common phenomenon with expansion/contraction of the frames or something similar? Regards, Chris I've yet to build one of these, so no direct experience, but it does sound like it might be a heat expansion issue. A more powerful iron might be able to make the frame to PCB joint quicker, so there is less time for heat to travel along the frame side, expanding it. Confining most of the heat to the joint area itself. Are you soldering all the spacers to one side first, then soldering them to the other side frame? Could putting some on one frame and some on the other first help, before joining the two sides together? To me it seems that the frame will bow so that the frame to PCB joints soldered last will be on the inside of the bow as it cools and contracts. Leaving plenty of time to cool between making each joint joining one side to the other could also help, as could heat shunts clipped on the frames each side of the PCB. Mim Link to post Share on other sites More sharing options...
Caley Jim Posted April 20, 2018 Share Posted April 20, 2018 Are there any particular tools that are useful for 2mm and may not be in a regular kit used for 4mm plus? In addition to those which have been already mentioned, all of which I heartily endorse, I find a small hand vice such as sold by Squires (see page 32 of their catalogue). It is invaluable for holding small components while you file them and particularly for holding small etched parts while you remove the last remnants of tags. For the latter job a fine India stone is also invaluable as it won't snag and distort the part in the way a file might. Jim Link to post Share on other sites More sharing options...
chrisveitch Posted April 28, 2018 Share Posted April 28, 2018 I've yet to build one of these, so no direct experience, but it does sound like it might be a heat expansion issue. A more powerful iron might be able to make the frame to PCB joint quicker, so there is less time for heat to travel along the frame side, expanding it. Confining most of the heat to the joint area itself. Are you soldering all the spacers to one side first, then soldering them to the other side frame? Could putting some on one frame and some on the other first help, before joining the two sides together? To me it seems that the frame will bow so that the frame to PCB joints soldered last will be on the inside of the bow as it cools and contracts. Leaving plenty of time to cool between making each joint joining one side to the other could also help, as could heat shunts clipped on the frames each side of the PCB. Mim Thanks for that - I honestly can't remember what order they were added as it was built a few months ago, left to one side (with all the other projects) and I then recently tried to fix it. I'm pretty sure I'd have done them end-to-end, i.e. both joints on one spacer, then then next spacer, etc. Your conjecture about the direction of the bowing being on the inside of the last joint soldered certainly fits with what I'm seeing. Maybe time to try a few heat sinks if I get time this weekend. Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted April 28, 2018 RMweb Premium Share Posted April 28, 2018 I'm building an Association replacement Pannier chassis and have a persistent problem with the frames bending slightly when soldering in the spacers. I've tried redoing them a couple of times and always get the same (or similar) result - I check the spacer sizes are correct, frames are straight etc. but after the last spacer is soldered in they come out of the jig bent to one side at one end. I've got it down to about a 0.4mm bend along the length of the chassis, but it's not right and I don't know what I'm doing wrong. Is it just me, or is this a common phenomenon with expansion/contraction of the frames or something similar? Regards, Chris I have encountered your frame issue a few times in the past in a variety of scales. Almost inevitably it has proved to be a frame spacer not truly square or sitting dead square in the correct position, especially with the etched/bent 90degrees type. Occasionally it has been the frame twisted or bent a bit, but not often. The errors have been small, tiny in some cases, but enough to throw things out. Your description says to me that one or more of the PCB frame spacers is not aligned correctly on each opposing frame, a mis-match between the sides. Could I suggest you remove all the spacers, clean up the frames, make sure all bits are true, and start again. Sighting along the flat sides of the frames will show up the slightest kink/twist, which is all such a problem needs to exist. Placing them back-to-back will show any differences in spacer location points. It can be slight enough that they will still drop into the jig. I have found that the spacers don't need to be a very tight fit as if there is the slightest error in them this will stress/twist the frames. I take it you are using the PCB frame spacers from shop 3? Izzy Link to post Share on other sites More sharing options...
chrisveitch Posted April 28, 2018 Share Posted April 28, 2018 I have encountered your frame issue a few times in the past in a variety of scales. Almost inevitably it has proved to be a frame spacer not truly square or sitting dead square in the correct position, especially with the etched/bent 90degrees type. Occasionally it has been the frame twisted or bent a bit, but not often. The errors have been small, tiny in some cases, but enough to throw things out. Your description says to me that one or more of the PCB frame spacers is not aligned correctly on each opposing frame, a mis-match between the sides. Could I suggest you remove all the spacers, clean up the frames, make sure all bits are true, and start again. Sighting along the flat sides of the frames will show up the slightest kink/twist, which is all such a problem needs to exist. Placing them back-to-back will show any differences in spacer location points. It can be slight enough that they will still drop into the jig. I have found that the spacers don't need to be a very tight fit as if there is the slightest error in them this will stress/twist the frames. I take it you are using the PCB frame spacers from shop 3? Izzy Thanks for that - yes, I'm using the shop 3 PCB spacer strip. Link to post Share on other sites More sharing options...
Stephen 28 Posted April 29, 2018 Share Posted April 29, 2018 Emphatically, a decent vice is required. Quite expensive, but worth every penny. http://www.cooksongold.com/Jewellery-Tools/Precision-Bench-Vice-prcode-997-1080 I could not produce my engines without a similar version. Tim Cooksons have a free postage offer on this weekend. I have just ordered one of these vices using it. (No connection other than as a customer). Link to post Share on other sites More sharing options...
RMweb Premium dhjgreen Posted April 29, 2018 RMweb Premium Share Posted April 29, 2018 Cooksons have a free postage offer on this weekend. I have just ordered one of these vices using it. (No connection other than as a customer). Must register to buy, place of birth mandatory; what!!! Link to post Share on other sites More sharing options...
Nigelcliffe Posted April 30, 2018 Share Posted April 30, 2018 Must register to buy, place of birth mandatory; what!!! So, register with "Trumpton", and a birthday of 1st Jan 1950, or similar nonsense data. Link to post Share on other sites More sharing options...
modfather Posted April 30, 2018 Share Posted April 30, 2018 Could any of the panel please furnish me who a copy of the Stephen Harris instructions for 16T opens, plate, catfish and grampus please? The originals were put in a very safe place before emigrating... Link to post Share on other sites More sharing options...
2mm Andy Posted April 30, 2018 Share Posted April 30, 2018 Could any of the panel please furnish me who a copy of the Stephen Harris instructions for 16T opens, plate, catfish and grampus please? The originals were put in a very safe place before emigrating... I think I've got instructions for all these. Will scan them for you tomorrow. Andy Link to post Share on other sites More sharing options...
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