Another Paddleducks build log

Gallery, Projects and General > Project Logs

<< < (61/70) > >>

sbwhart:
:offtopic:

Got this one from Aldi a few weeks ago £12.50 with lots of bits, 240V nice a chunky with plenty of humph, at that price you can risk nackering it up as a tool post grinder.

Stew

spuddevans:
My "dremel" is in fact the Axminster version, and I was going to try using the flexible extension part of the kit as it is only about 3/4" thick ( or there-abouts ) and hopefully relatively easy to mount to the toolpost.

I figure that even though the bearings may not be rated for this sort of application, it will not be seeing much use, I intend to turn down using conventional methods until I get really close, and then I will grind only the 2 3mm sections after hogging out the middle section. That being the ( theretical ) case I dont see too much wear if I take it really easy. ( famous last words ), and even if it does cause any damage, the damage will be to the flexable extension and not to the tool itself.

But like I said, I'll have another search in the metal stocks to see if I can find the 6mm silver steel, hopefully I will find it.

Tim

NickG:
Stew I got that one from Aldi about 6 months ago - same price!

spuddevans:
Well, talk about resurrecting an old topic :bugeye: I cant believe that it has been over 4 months since I posted any updates.

Due to my better half's health situation, until recently I havent been able to spend much more than 20mins at a time in the workshop, which meant I hadnt made much progress on this build ( or on much else ). But things seem to have settled a bit to allow me a bit more time in the 'shop so I thought I'd update this build log.

To date I have remade one (already remade :bang: ) piston valve and made a new steam chest for it and succeeded in keeping a much closer fit.

I also have modified the pistons to accept o-rings.

I then started to chase down and fix as many causes of friction that I could.

I bored the bearing blocks all the way through, they originally had a 5mm thru hole for the crankshaft, and a 8mm diameter pocket each side for the ball races. I have since found that there was some friction being caused by the 5mm sections, so I got all 4 bearing block bored out to 7.8mm in the mill, then I carefully alligned them all together in the vice and used a 8mm hand reamer to open them out the final 0.2mm. Then I stuck some 8mm silver steel rod thru the 4 and gave them all a wipe over some 600grit w&d on a surface plate.

Then I loosely assembled the bearing blocks onto the baseplate, stuck the 8mm rod thru them, and then tightened them up. Then I lapped them using the same 8mm silver steel rod and some T-cut to get them spot on. Then I re-assembled the crankshaft with all the ball races and the difference was unbelievable, silky smooth and free.

After re-assembling the whole engine and re-timing it I applied some air to it and........

It ran :D :D :D :D ( for about 20 secs until my little airbrush compressors tank was empty )

It seems to be quite an air-hog at the moment. I got it started on 50psi and it ran until the tank got down to about 25-30psi. I havent got any gasketing installed at the moment, nor any stuffing in the glands, so that will be my next process, chasing down the air leaks.

I also have noticed that there is a lot of air that seems to going straight thru the valving to the exhaust without meeting the piston, so that too will have to be investigated.

Overall I am quite pleased that I have got it to run on my little compressor, previously it had not had enough stored air to turn it over more than a couple of revolutions.

So while it is taking me ( quite ) a while, it is satisfying that at least there is some progress to report, hopefully in the coming weeks I will be able to post up a video of it working.

Tim

sbwhart:
Hi Tim

Pleased that things are settling down for you, and that you've had some success with the engine, look forward to seeing the video.

Stew

Navigation

 Message Index

Go to full version