Eddit Robot Platform Problem
I hope this is the right section for some advice on the Eddie Robot Platform. It seems I have fallen at almost the first hurdle during the construction of my Eddie kit.
During the assembly of the Motor Mount and Wheel Kit (specifcally point 2) the axel bearing has become wedged in. It seemed tight initially but I thought it would slide in without too many problems but it wasn't the case and now I can't move it at all.
I did search for someone else with the same issue but this was the closest I could find ->
http://forums.parallax.com/showthread.php?129087-Motor-Mount-and-Wheel-Kit-27972-Disassembly-Help
In this post the solution was to heat the bracket in the oven and put the bearing in the freezer and it slid in no problems. I would certainly do this if I could get the bearing out. I don't want to use excessive force as the instructions say.
What can I do? Is there any technique or tools to rectify the situation? Any help is appreciated as I am really stuck.
During the assembly of the Motor Mount and Wheel Kit (specifcally point 2) the axel bearing has become wedged in. It seemed tight initially but I thought it would slide in without too many problems but it wasn't the case and now I can't move it at all.
I did search for someone else with the same issue but this was the closest I could find ->
http://forums.parallax.com/showthread.php?129087-Motor-Mount-and-Wheel-Kit-27972-Disassembly-Help
In this post the solution was to heat the bracket in the oven and put the bearing in the freezer and it slid in no problems. I would certainly do this if I could get the bearing out. I don't want to use excessive force as the instructions say.
What can I do? Is there any technique or tools to rectify the situation? Any help is appreciated as I am really stuck.
Comments
There's a tight tolerance between the bearing and the bearing pocket in the bearing block. It should be less than 0.0005" of clearance and sometimes this is too tight, maybe as a result of anodizing (which might grow the bearing pocket) or tool wear (tool diameter becomes smaller over time). But you don't care about why we have this problem - you just need to solve it since we didn't test fit this assembly for you.
So, the bearing should press in fairly easily. You need to be careful not to press it in at an angle of course, as this will cause it to get stuck. As long as you can exert force on the sides of it evenly it should seat into the pocket.
I don't know what kind of tools you have at home (or work?) but you probably don't have an arbor press. There's a safe way around this with a hammer [but what kind of hack would suggest using a hammer on a machined part??]. Place the bearing block on a very solid flat table, with a thin cloth underneath so the table and bearing block don't get scratched. Then, find a round wooden rod (1" diameter or so, a few inches long) and place it over the bearing. Check to see that everything is square and tap, tap, just go ahead and tap it in with your hammer. It should seat in the bottom of the pocket.
If you are still having trouble I'll pull one from our inventory, check the fit, and send you a replacement. It's no problem if you're in the UK - if we're busy touting the quality of American manufacturing then we better be willing to support our squawking with real results. That's why I'm here. Let me know how it works out, and drop me an e-mail if you need parts since I don't get to check in on the forums nearly as often as I'd like. It's only Tuesday and with FedEx we should have your robot rolling by this weekend.
- Ken Gracey
I have no arbor press but I will give your suggestion a try with the cloth, wooden rod, hammer and some tapping.
I'll let you know the results which will hopefully be positive. Many Thanks
Just for the record - for the second motor I took the precautionary measure of cooling the bearing and heating the bearing block and this time it slid in immediately without any of the trouble I had with this first one. I can't be sure it wasn't a stroke of bad luck with the first bearing but this technique definitely seemed to help me.
I haven’t completed the full Eddie build as yet but hopefully I won’t run into any further problems from this point onwards.
Many thanks for your help Ken – it is good to know there is such great support behind the product.
Excellent :thumb:
I'm a little late to the party here, but that's (heating and cooling) exactly what I was going to suggest. The cool thing about doing it that way is that when the temperatures equalize, the bearing is locked in nice and snug too.
Keep us updated on how you're doing!
-MattG