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: Leadscrew suppliers|
For some reason 2.5mm pitch screws are vanishingly rare which is a shame since that is what I need for a Boxford crosslide.
|Thread: Mill unexpectedly cutting crooked|
I'm an absolute beginner but it occurs to me that if the cutter isn't perfectly aligned with the spindle it would describe a cone which would create an undercut, for example if the cutter was bent. If it happens with different cutters then maybe there is some crud in the spindle nose that prevents the collet from seating properly or maybe even the spindle is bent?
|Thread: Pulley Sizes For An X2 Clone Conversion|
Thanks Neil, is your conversion single speed? Looks like a 4:1 reduction which equates to the low range on the standard machine as far as I can judge.
Edited By William Chitham on 25/06/2020 12:42:56
Ok, I'm convinced, poly v it is. Some further questions occur to me:
How many ribs? 4 seems common, but I have seen suggestions that 3 or even 2 would be adequate. Less ribs means less "stack" height which might be a good thing but more important seems to be the built in torque limiting safety factor - fewer ribs presumably slip sooner. The weak intermediate gear that we want rid of seems designed as a sacrificial component, primarily protecting the back gears buried behind the spindle which will be redundant anyway but is it realistic to hope that belt slip might reduce damage to cutters or workpiece perhaps in a misread decimal point sort of scenario? It might be interesting to make 4 rib pulleys and try running 4,3 & 2 rib belts to see whether slip could be provoked.
How necessary is the flange? Seems to me that it is only going to make speed change more awkward. If it is keeping the belt on when running then something must be seriously wrong with alignment.
Is there any reason to try to extend the speed range beyond the standard?
Thanks Clive, that all makes sense to me, I absolutely take the point about the small form tool. I'm actually in the process of making a bed clamp for a dial gauge which would serve the purpose for spacing.
Crikey, there should be a separate thread for most radical X2. Looks as if you've addressed the terrible fine feed as well, does the spur on top of the spindle pulley drive a powered feed?
Thanks, is that on a similar machine? Do you use the low speeds much?
Thanks Keith, staring me in the face of course. Spec looks fine, 20mm on the motor and 80 on the spindle gives me the 4:1 and the 2:1 for the high speed should be easy.
I am keen to make this myself because I'd rather invest time than money and I might learn something along the way.
Clive, I can see that a poly belt might be superior but all the conversions I've seen so far use a basic V. Not sure how machining 5 precisely spaced grooves is easier than one big one, could you expand on that?
Having broken my second intermediate gear I'm contemplating a belt drive conversion for my X2 clone. This looks to be a suitable belt: belt but I can't find any specs for pulleys, specifically I want to know the smallest practical. If I drive the spindle direct I reckon I need a reduction ratio of roughly 4:1 to match the existing low gear setting. The spindle pulley is limited to around 80mm pcd so the motor pulley would need to be 20mm pcd to achieve that - seems a bit tight but it is a small cogged belt. Any thoughts?
|Thread: Single point threading|
Three suggestions from a beginner:
Grind an HSS tool with a narrow nose that you can use in with the centre.
Turn the blank long enough to get the centre in to support it then cut to length after threading.
Also maybe skip the gutter or cut it with a radiussed tool to reduce the stress riser.
|Thread: Telescopic bore gauges.|
This Old Tony recently posted a video showing how he dismantled and fine tuned bore gauges to make them work smoothly: **LINK** . I suppose he is shortcutting the natural "break in " process that makes old tools feel nicer.
|Thread: Boxford change gears for screwcutting.|
Hi Terry, as a fellow metric Boxford user I absolutely agree with you, it is an excellent little program. I do have a copy, I have sent you a message with a link, contact me if it doesn't work
|Thread: New DTI "Glass"|
If anyone is interested I put some photos of the process in an album. In brief I turned a wooden male form; balanced a 1mm acrylic blank on top; heated with a hot air gun till floppy; pressed down over the form with a plywood "washer"; put the acrylic wrapped form back in the lathe and "parted off". It took a few attempts to learn to read the state of the hot acrylic and it was tricky to cut accurately to a diameter but I managed to get a good snug fit in the bezel eventually and only used one A4 sized piece of material.
I picked up this DTI at a jumble back in February. It was a bit sticky and the pointers were out of phase so I didn't pay much for it. I dismantled and reassembled it and works fine now but the plastic "glass" is yellowed and loose enough to pop out without much encouragement. Any thoughts about replacing the glass? I'm thinking maybe 1mm acrylic which seems readily available but I don't know if that is oil resistant.
|Thread: What is This?|
I think it is for getting Boy Scouts out of horses' hooves.
|Thread: Airline Fittings?|
I have split the output from my compressor into clean and oily lines. The clean line has a filter and dryer and everything that plugs into this uses Euro type fittings. The oily line has a filter and lubricator and uses PCL fittings.
|Thread: Help with a boxford c|
On my CUD the holes in the brackets for the intermediate shaft are slotted so I was able to adjust the tension somewhat by moving the shaft backwards and forwards.
I just refurbed a micrometer and used an Edding 950 paintmarker following a You Tube recommendation. I bought it from Zoro, they also do a Markal brand equivalent. They are meant for marking up fabrications, metal stock etc and will supposedly write on dirty rusty oily surfaces and be permanent. Easy enough to apply by the rub on wipe off method, only just done it so can't vouch for permanence.
|Thread: Calculating DRO For Mill Z Axis|
Just the job, I thought it must be possible.
That would work but might require a rather convoluted mechanical connection between the two.
While my printer toils away I've been pondering the DRO installation on my fantasy mill. Obviously it is a knee mill with a quill and I'm wondering if a 3 axis DRO can be set up so that the Z axis displays the product of two scales, one on the quill and one on the knee? In other words any movement down on the quill would be added to any movement up on the table to show the cumulative result.
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