Here is a list of all the postings AJAX has made in our forums. Click on a thread name to jump to the thread.
|Thread: Best way to run 400v 3ph motor on 220v|
My Eagle surface grinder came with a 440V motor that was hard wired star configuration. After a test run using a 240V VFD I stripped the motor down and dug out the star point from the windings. I then rewired in Delta configuration. It was a relatively quick and easy job.
I'm not the only one to have done this. Whereabouts are you? Someone may be able to assist.
|Thread: Car boot gizmo identification?|
There is a listing on eBay. 4 x Vintage Disston D8 saws for £40, including postage.
|Thread: Looking for help valuing two lathes|
Chris, I've sent you a message. It should be in your Inbox.
|Thread: motor insurance rant|
This might be of interest
Edited By AJAX on 15/06/2022 22:10:58
Received a renewal reminder from RAC Car Insurance this week.
Last year's total = £115.25
Renewal price = £213.39 !!!!!!!!!
I tried to cancel online but was unable to do so. You can renew online (with no interaction) but to cancel you have to contact a customer representative.
I've changed insurer.
Zenith Insurance. Fully comprehensive. £0 voluntary excess. £109.54
|Thread: Fortis Vice|
Yes, wire wheel on an angle grinder. The surface rust cleaned of easily. It was then wiped over with an oily rag (hence the slightly gloss finish) as I have no plans to repaint it now. I did one small repair/modification to make the quick release work correctly, and I will make some jaws when some suitable scraptonium comes my way. For now, it's just sitting under a bench.
I'm another owner of a Fortis Steel vice (pictures coming soon...) and although I cleaned it up a while back I don't recall there being any paint to remove. And mine is "Ministry of Supply - Property of HM Government" if that helps indicate the age.
|Thread: Denham Lathe Restoration|
The "motor date" probably refers to the British Standard, bss170:1939 and not the date of manufacture.
|Thread: Powering a Suds pump?|
By placing two or more capacitors in parallel you are effectively increasing the plate area and so increasing the effective capacitance. When placed in series, you are increasing the distance between the plates and this reducing the effective capacitance.
|Thread: Review prejudice - who do you trust?|
The worst reviews of all are the sponsored Vine reviews on Amazon. Don't trust them!
|Thread: More beginner questions|
I disagree with the comment to scrap it just because it's an unknown grade. Quite often, I and many others find a use for bits from the scrap bin. If he can't turn it with a reasonable finish now, put it to the side. He may be able to do so when the lathe and tooling is sorted.
I agree with the suggestion of trying some EN1A Pb. Aluminium alloy such as 6082 is another option.
|Thread: What does this circuit do ?|
I can't quite read the capacitor markings, but it may well be 1000uF and not 10000uF (10mF).
I agree with your comment regarding fuse on the supply side, but if the capacitor is large there may be an inrush current sufficiently large to blow the fuse.
The circuit is a half-wave rectifier with capacitive smoothing, but in this application (DC supply) the diode protects against reverse bias and the bulk capacitor improves load regulation by reducing ripple.
The open circuit voltage should be around 0.7V greater than the output voltage under load. Consider the IV characteristics of the diode to understand why.
|Thread: mini grinders|
I use one of those pencil type air die grinders. Cheap ebay job. Works really well, and I've given it some abuse. 30 to 50k rpm if I remember correctly. Doesn't use much air at all.
|Thread: T-slot cutter|
I'm always interested to see simple homemade tools that work.
|Thread: Myford ML4 change gear modification|
George (and others) thank you for the information.
It appears the consensus is to use pins and holes and not to bother with keys. I'm happy with that as it's the easier option.
I have some low-strength Loctite (about 6 unused bottles if I remember correctly!) so I will probably use parallel pins and the through-hole option.
That's another consideration. Thanks.
I recently acquired a Myford ML4 which came with a limited number of change gears. The final driven gear has an unused keyway, and the leadscrew is not keyed (it has a small flat) and relies on a bush (fixed with a setscrew on the flat) that has a small pin that engages with the side of the gear wheel. All the torque is transferred via this small pin. Maybe that's a good idea, maybe not. I would expect it to be a likely point of failure in the event of a crash.
I happen to have a collection of keyed Myford change gears that could easily be modified to work on the ML4 lathe by adding a small hole for the pin. However, I'm wondering whether it would not be more sensible to mill a keyway slot and fit a key to the leadscrew. By making this one modification I could then use any of the change gears at my disposal.
I would welcome comments.
|Thread: Boxford AUD/BUD single phase conversion|
If it turns out to be hard wired star, don't immediately reject the motor. I recently rewired such a motor by digging out the star point on the windings. It wasn't difficult to do.
Regarding all the existing switch gear, I would ditch the lot when fitting the VFD. A modern rotary or toggle switch is easy to wire up for controlling motor direction.
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