Paddleducks
Other Marine Models => Live steam => Topic started by: smuttley on March 01, 2009, 10:35:22 PM
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I'm stuck, and can't find the answer anywhere on the net.
I have built twin beams (new engine build) and got to the stage were I want to fit some small 4mm ID, 8mm OD bearings into the beams on each end, I have also milled the push rod forks. I thought the best way to install them was to drill out 8mm with end mill drill, so as to be in the centre of the beam (thickness), and thread a grub screw to hold bearing in place, this will then see the the bearing out side secured. But I can not get my head around on how I can secure the centre of bearing, so the centre of bearing hub, don't turn, is that making sense? The bearings are small, so not much room to play with.
How do you guys install bearings, what is the best method?
You can tell I'm new at this,
Regards
Steve
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I'm no engineer, but I'd be looking at Loctite to securely fix the bearing in place..... I'm sure there will be other suggestions?
Regards
Eddy
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Two normal methods suggest themselves when installing bearings. The first is to make the hole an 'interference fit' and press the bearing into place using a vice and a pin slightly smaller than the OD of the bearing.
The other is to again make the hole an interference fit, place the bearing in the freezer and heat up the beam. When the bearing is very cold, and the beam is very hot - drop the bearing into place. The beam will contract, the bearing expand and be securely held in place.
A third method is to use a roll pin thru the beam and into the bearing - but be sure to through drill the hole for the roll pin so that you can remove it if neccessary by drifting it out from the other side.
Hope this helps
Stuart
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Sorry for the late reply, I have been laid up for a bit.
Thanks for your suggestions guys, I should be able to get to this, this week and hopefully use one of your methods,
Again, thanks for that,
Regards
Steve
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Hi PD's....& good to see you are back on your feet Steve :bravo...we could never doubt the correctness of comments here by Stuart....[but how do I drill & ream a hole that will be an interference fit to suit my ......say my 3/8" OD roller bearing....that means the hole will need to be say 0.3740>0.3745" diameter]
{{Bogstandard may come in here & correct me}}....however in the grand scheme of things I would go with the comment from Eddy.....[Loctite]
Just drill a 3/8" diameter hole which will end up approx 0.376>0.377" & my precision 0.375" OD bearing will be a rattly fit in the hole
Loctite products are many in number & applicational grade ..... :ranting...& way too many for the considerations of our craft
That little 10 ml bottle of Loctite "243 -Thread Locker" will also more than adaquately secure & lock small ball bearings.....only qualification = cleanliness.... :oops...just ensure all surfaces are cleaned of any oxide, degreased & Loctite 7471 Primer is preferable.....
The same would apply to the ID of the ball bearing+shaft....but you may need to provide a series of small helical wicking paths in the shaft to allow the Loctite to float to the ID of the ball bearing....I am sure you know what I mean but ....:shhh......Derek
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Just make sure the Loctite does not get into the bearing race or every thing grinds to a halt.
Regards,
Gerald
PS the amount of interference for a fit can be found in Machinery Handbook.
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Just drill a 3/8" diameter hole which will end up approx 0.376>0.377" & my precision 0.375" OD bearing will be a rattly fit in the hole
Nice to be back on my feet, or standing at the mill.
Yep drilled the hole and rattly it is, I have six bearings to install (two beams), so will use the locktite as suggested on one of them first, to ensure I get it right. I can turn down the centre pin OK on the Lathe, so as to be a snug fit and a little Locktite should hold the little bugger,
Thanks for help with this,
Steve