Gallery, Projects and General > Project Logs
Valve Base
Darren:
That looks good Dave, a lot of people really favor these Boxfords from what I can tell.
Alas I have an ambitious project in mind for the future in that I wish to turn a new 12" or even 13" platter for my record player.
On those lines I'm thinking a Colchester Student for example, I also wish to turn 30mm S bars up to around 300 or 400mm long and drill and tap the ends.
I can do the last bit on my S&B if the new lathe isn't able.
I know from experience, that I want the next lathe purchase to be my last, famous last words.
Thanks John, I will speak to Ralph hopefully face to face sometime. I have been playing with metal for a long time.
It's the machining/engineering that's new to me...loving it though.
Did you see the link to my now very old web site? http://homepage.ntlworld.com/darren.dean/index.htm
Darren:
"House work" today was clearing ground at the top of a high and very steep ground against a wall for preparation to planting a hedge. 100 Copper beach in this case.
Is that modding?
Ok, so taking a break from that this evening I thought that it was about time I got back to my amplifier build.
Tonight I laid out the various pieces on top of a chassis box.
At the back is the output transformer. Upside down in this instance. This connects the circuit to the speakers. One speaker in this case as these chassis are built as a pair in the form of two mono blocks for stereo reproduction.
At the front is the valve secured by the parts I've been working on in previous posts.
The orange wire is just stopping the valve from falling over. These fittings will be secured with a 6mm bolt from underneath. They will need electrically isolating from the chassis so I'm thinking of making "top hats" to facilitate the insulation. They will be subjected to some high temperatures, enough to singe wood so the top hats will be fabricated from Teflon rod as seen in the pictures.
A closer view
And one from the side showing more detail.
Transformer the right way up
Now then, I need to cut a hole in the chassis for the transformer connecting wires. I have a hole punch as shown in this picture, but it's a little small. I need to be careful here as the highest voltage is 1,200 volts DC. So a clearance gap from the connection to the chassis needs to be large enough for the voltage not to be able to jump the across. The hole punch is 50mm and I need a min of 55mm. 60mm would be better and tidier.
The chassis is 1.25mm thick steel and is hard work for a hole punch which can cause distortion, otherwise I would make one the correct size.
So I'm thinking of purchasing a Bi-metal hole saw of the correct size required.
But maybe someone here can suggest another way? I'd like the result to be tidy, spose that goes without saying.
Bernd:
Have you ever heard of a "tree panning" tool? I think that's the American name for it. It's used to cut out holes in wood if the hole is bigger than the biggest drill you can get and also to make wooded wheels.
I know I've got several. I'll go look and update this post when I find them.
Bernd
Darren:
Do you mean something like this Bernd?
http://cgi.ebay.co.uk/1-New-Hole-Saw-Kit-Adjustable-Metal-2-pc-Circle-Cutter_W0QQitemZ190275185971QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item190275185971&_trksid=p3286.c0.m14&_trkparms=66%3A3|65%3A7|39%3A1|240%3A1318
Cheap enough, but are they ok with steel, those blades look like they would snap at the slightest provocation.
Saved a pic for future ref when the auction has long gone !!
bogstandard:
Darren,
I have some of those hole punches up to about 3", but as you say, at the thickness you are working with, they are very hard work. RS do a range of all sorts of sizes and shapes, but are rather expensive.
The hole saw method would be favourite, but stick with a good quality one if drilling thru steel, the cheaper ones have a tendancy to go blunt rather quickly. The Starrett range, to me, are the better end of the bunch for general steel drilling work.
But you will need to make sure you have a very rigid setup for the plate holding as they can be rather fierce on start up and break through.
The trepanning tool will work, but you have to take it v-e-r-y steady, and use only a fine feed down handle, a normal drill press handle will be putting you in the 'trouble area', and could easily break the tip off or rip the cut off centre, especially as you are breaking through. That system is very flexible for sizing, but a bad 'not very rigid' design.
You could easily make a more rigid trepanning system yourself, if you were doing a fair amount of the same size. Base it around a flycutter design but rather than an angled base, have it flat on the bottom with a rigidly fixed robust cutter in a fixed position for the job.
John
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version