Here is a list of all the postings William Chitham has made in our forums. Click on a thread name to jump to the thread.
|Thread: Loctite For Delrin?|
Reading Tim Stevens' thread on making a gear for a Colchester thread indicator it was suggested that he might turn down the splined hub of a damaged gear and make a new toothed outer to fix on with Loctite. It was also suggested that he might make a new gear out of Delrin or similar. I think these were separate suggestions but could they be combined? Would Loctite 638, say, stick Delrin to cast iron?
|Thread: Advice on Heat Treating|
Obviously I will be knocking it off the bench with grim regularity like everything else! Impact shocks aside I think the most vulnerable bit in normal use will be the "ears" of the dovetail which will only be about 0.75mm thick and will tend to be spread by the force of the locking collar screwed up from beneath.
Sorry Tug, thanks for your informative replies but my reference to colour was just in terms of using it as a guide when tempering. I plan to cold blue these parts when finished, I have some Phillips bluing solution which works well.
Thanks for all the suggestions. I don't suppose I would ever wear them out if I didn't harden them but I am using the project as a way to learn new things and I haven't tried heat treating before so... I think I will go ahead and harden them then heat treat in the oven, not least because that will be an excuse to cook a pizza this weekend. In the oven is it a case of holding them at temperature for a certain time then letting them cool gradually?
Of course I might be remaking the parts as tonight's challenge is to mill the dovetail slot in the end of the threaded one with a home ground cutter.
I am making a DTI holder from drawings by Stefan Gotteswinter. He specifies that some of the parts should be hardened and, presumably, tempered. These bits (not finished yet) are made from 01 Tool Steel, I am pretty confident I can harden them by heating with a torch then quenching in oil but not so sure how to go about tempering - or if that is even necessary? I understand the principle of reheating and watching for colour change but that usually seems to be done on larger parts where the heat can be applied at one end and the colour change observed as it migrates up the part. These are only 30mm long overall and besides I think I want the whole thing at the same state. Any advice would be welcome.
Edited By William Chitham on 17/03/2021 11:23:55
|Thread: Indexable tool insert replacements|
I've gone as far as watching some of your movies! Love the Thompson engine.
Unfortunately I am neophyte, not a master. I can say that I recently bought some Korloy turning inserts and a Vardex thread tool holder & inserts from Cutwel following a phone conversation with a salesman there who seemed to know what he was talking about. I haven't used the turning inserts yet but have had good results with the threading tools.
|Thread: Two or three axis DRO|
From my limited experience with a Chester 626 definitely 3 axis with 4 scales - X,Y and quill and table combined through a summing interface for Z.
|Thread: Indexable tool insert replacements|
I think this thread is typical of a kind that are hopelessly frustrating for a beginner. Lots of people are happy to pitch in with common sense advice like "buy the best you can afford" or "I bought dozens for tuppence and they are great" but at the end the OP is none the wiser and is left to start randomly buying inserts till he or she gets lucky. Why is no one ever prepared to stick their neck out and say "I bought this specific insert from this supplier to cut this material on this lathe and it is excellent (or rubbish!)".
|Thread: Digital Callipers - again|
I've had a couple of Aldi cheapies which seem like spectacular value for money but in a fit of extravagence I bought a Mitutoyo. This does feel like a better quality device and it doesn't need zeroing every other use but I was dissappointed that it doesn't have any functional advantage over the cheapies - in particular I thought it would have the ability to store a second zero so you could go back and forth between the origin zero and a saved zero (afraid my terminology is probably not correct but I hope this makes sense). This is not the case. The other problem is that it has no auto switch off and I'm pretty sure I didn't turn it off last night so when I get into the workshop this evening it probably will be dead. Bah.
|Thread: Quill DRO Scale For 626 Mill|
I finally have the DRO installed how I want it on my 626. Last stage was to fit a scale to the quill and plumb it into the console combined with the table scale through an M_DRO summing interface. Space is tight and I had to shorten the scale I had but I'm happy with the result and having both quill and table on the Z axis is brilliant. I'm using the depth stop nuts to hold the scale brackets in place for the time being but when I dismantle the head for further modifications I'll drill and tap for securing screws.
|Thread: Wheel for model jeep|
Hand turn from wood or some kind of nylon/delrin/acetal what have you?
Or looks like it would lend itself to casting. Mould from plaster, silicon, plasticene, papier-mashe, gumstrip. Cast in resin or similar.
|Thread: Economy Spiral Flute Taps?|
Hats off to APT. Ordered three taps and a couple of inserts yesterday, arrived today.
And they have a sale on.
Thanks all, particularly pleased to discover APT.
Brilliant, don't know how I overlooked these.
I've had plenty of use out of my Aldi tap and die set but I've given up waiting for them to come up with a set of spiral flute taps. Can anyone suggest an alternative supplier for an economical set, say M3 - M10?
|Thread: DRO Scale Rewire|
I had to replace one of the encoders on my Chester 626 mill and had a spare cheap one from China to hand so I did some investigating and found that though the plug was wired differently to the Chester Quark brand DRO system it was very likely the basic unit would be compatible. The pin assignments are detailed in the manual so I chopped off the plug, rewired it the Quark way and bingo, it works. I also found some very helpful information on scales on the Touch DRO site which explains how to identify the wiring scheme using a multimeter.
Edited By William Chitham on 13/01/2021 14:22:59
|Thread: trapezoidal rod + leadscrews|
Can't find 2.5mm pitch for us Boxford owners though.
|Thread: Wallis & Steevens Water Cart in 1' scale|
That's beautiful. Are the letters commercially available or did you make them somehow and looking at the album how did you do the wheel hubs, are they cast?
|Thread: Helical Milling On A Small Mill Anyone?|
I have been reading a lovely book about milling machines and the uses thereof (published by Browne & Sharpe in about 1911 I think) and I was particularly interested in the explanations of helical milling to produce spiral flutes in drill bits etc. Coincidentally a friend asked me if I thought I could make a whopping great tap to cut threads in wood - 2.5" x 2tpi or thereabouts. Seems like an interesting project I thought and went to look at the change gears on my Boxford. To achieve 2tpi I would need 4 turns of the leadscrew per rev of the spindle which I think is achievable but is it sensible? So I'm wondering if it would be better to try to mill it. A bit of googling has thrown up some videos of helical milling on manual machines using manufacturer or homebrewed geartrains driving dividing heads but all on hefty industrial sized mills. Has anyone tried it on a hobby sized machine like my 626? I can imagine making a geartrain to connect the x axis leadscrew to a rotary table say any advice or experience from someone who has done it would be very gladly received.
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