Here is a list of all the postings Martin of Wick has made in our forums. Click on a thread name to jump to the thread.
|Thread: Choice between cheap mini milling machines.|
What will I sacrifice if I go to a smaller machine?
Rigidity, power and usability - you will be confined to very light cuts and may have great difficulty milling harder materials - you will probably be OK on non ferrous stuff. anything else will just be a frustrating pain in the arm as you wind the table back and forth a gazillion times.
Is there a significant and consistent difference between the available makes
for machines in the same class, not really - brushed vs brushless / belt vs VSD / bigger vs smaller table / spindle taper etc.
The only thing that really matters on a mill is mass rigidity and power . Every time I have brought a hobby mill, I have always regretted not getting the next size up. Still looking for the perfect Centec - one day....
|Thread: Myford super 7B Chuck threads|
large one with the nose on front is probably for mounting a chuck on a rotary table
why? wouldn't you just bolt a chuck directly to the slots on the rotary table?
the one with peg on is a catch plate used specifically for turning between centres - likely will be tight because they are not used often (mine is and needs wringing on with lots of oil!). Should be left as is rather than turned into a chuck backplate.
Suggest you check your spindle for burs flats etc if the catch plate is really getting hung up as opposed to tight - should go on as it looks like Myford type
The Large undrilled one is no good as it has a nose on the front which has the threads
Difficult to see or assess dimensions but if the thread is 1 1/8 in and of correct 12W form, you can clamp it to the face plate and bore out the register in the 'nose; section to 1 1/4 in to fit the lathe spindle to make usable.
I don't know if the backplate in the third picture from top between faceplate and catch plate is the 'large undrilled one' or just the one plate that you say fits.
items bottom right are lathe dogs for use with the catch plate when turning between centres'
the backplate that you say is too big for the chuck actually requires machining to the correct size with the correct register to fit your chuck
If you want another backplate, I would advise a new one from the usual sources rather than a used one (unless you can view and check over yourself). It will come as a threaded blank which you will have to machine to fit you chuck.
Google 'The Amateur's Lathe' by L Sparey on amazon and get a copy - you will find it very useful.
Edited By Martin of Wick on 03/01/2020 09:55:24
Edited By Martin of Wick on 03/01/2020 09:56:14
|Thread: Creality 3D For Christmas - Impressions so Far|
inspired my to have another try.
|Thread: Ml7 New Owner.|
re the drill arbour, lock down tailstock, place towel to protect bed and drill chuck and either use a deadblow hammer or normal hammer and piece of wood to protect the back of chuck and give a smart tap (or use a drift through the tailstock shaft if using ML7).
Check state of taper for burrs or scratches and remedy if necessary. Sometimes a thin wrap of appropriately cut paper with reduce propensity of chuck to spin but mostly technique is keep the speed up and the torque low when drilling.
Re the main chuck, as per Pete, It is always a bit tricky first few times and likely you will get one jaw too deep or one wont engage the scroll but stick with it and you will get there. If necessary, take all jaws out completely line up the scroll rotating backwards just past 1 slot, locate all jaws correctly in their numbered slots and try closing up again while keeping pressure on the jaws as you do so they engage the scroll correctly.
|Thread: Creality 3D For Christmas - Impressions so Far|
strewth! at 0.4mm nozzle too..
Thanks for that Andrew,
I have an old plastic frame Anet 8 project machine which I am in the process of re configuring into the popular Al profile frame version (project with more stops than starts).
Some time back I did try to upload a Ramps/arduino combination board only managing an epic fail after a couple of days - I must have reviewed every online video on Utube but still never figured it out.
Perhaps I will try a MKS board as there are less steps to loading Marlin, but how do you manage without an SD card reader? - does that mean that the control screen has to be changed to a version with SD as well? Are there any recommended for the MKS board?
With not much effort, results on my bottom end printers generally exceed expectations, the limit for me using a 32 bit machine is being restricted to Cura V15.x. (cant bring myself to pay for a slicer!) I did try to use a 0.2 nozzle for a while although it gave quite good results for small fine work it was very prone to clogging and sooo very slooow printing, gave up in the end. Might try again one day with a better quality nozzle and hot end.
I like the idea of calibrating the extruder on the output result rather than the filament input side - good tip.
My bone of contention with the 'economy' end of the 3d printer market is the hot ends are limited in the software to about 260 degrees (or less) and it appears to be something of an intimidating trial to load alternative user configurable firmware. I would like to try printing with polycarbonate and nylon one day.
It would be nice if someone produced a decent generic mainboard already loaded up with Marlin and some start profiles for the common budget machines, rather than having to nerd surf the web to piece together what is required.
|Thread: Myford super 7B Chuck threads|
To answer your question, I am not aware that Myfords produced S7 lathe spindles of any other form than W12 1-1/8" (unlike Boxford where an export version had a metric spindle nose).
If you purchase a new backplate from any of the regular UK vendors, it should fit your Myford (unless your machine spindle has undergone some from of damage or alteration). However, my experience with some new backplates is that they can be quite (very) stiff to get on and off initially and may need the crests in the plate relieving.
Regarding your existing non fitting backplates which I assume have not been machined to fit a chuck, purchase a combination Whit/metric thread gauge and measure up the thread and recess as instructed above.
If they appear to be of the correct dimension, then it may be that a good clean and oiling, or passing a tap through as suggested above will retrieve them. If the backplates were home shop made, it is possible that someone cut the 12 tpi with a 60 degree metric form instead of the correct 55 degree Whit form - In that case I am not sure if using a tap to correct the thread is possible - someone here will be able to advise...
If after remedials the backplates fit your spindle tolerably well, then machine as required to fit your chucks.
Edited By Martin of Wick on 02/01/2020 10:12:48
Edited By Martin of Wick on 02/01/2020 10:19:08
|Thread: 3mm drill hole too tight for 3mm bar|
Try this link for table BS shaft tolerances - scroll to bottom to get descriptive chose the one you want and look up on clearance/diameter tables
1 redrill leaning on the drill or try another make of drill (they are not all the same)
if fails measure accurately carbide bar
2 use a 3.1mm (or larger drill to suit carbide tool)
put a flat on the bar (as in grind with carbide (green grit) wheel I would suggest)
You wont get very far using emery paper on carbide.
|Thread: Hobbymat lathe - couple of questions|
As these are just hobby lathe change gears IMO t'aint worth the cost and effort of making them in metal.
option 1 the hard way - as you suggest, purchase a set of nylon minilathe gears - bore and bushed to suit but the bushing will need to be keyed to the bore in the gear. You wont get the whole range, but most of them. you could start just with the few common threads you think you are likely to use.
option2 my lazy way - acquire a cheap 3d printer, download a set of minilathe gears STLs from thingiverse, ,modify them to suit in Tinkercad and print whatever you want. You will suddenly find a myriad other things to print such as soft over jaws, chuck spiders, nudgers, dial clamps, angle gauges, micrometer holders etc etc too many to list as they say.
|Thread: Creality 3D For Christmas - Impressions so Far|
Interesting to see how you get on with gears. Using same printer with 0.4 nozzle, anything under mod 1 is a little rough on the tooth form.
You will also need to check/adjust carefully the wall count and thickness in the cura layer view. If that shows big gaps on tooth crowns, then there will be big gaps in the print and the teeth will be weaker. You have to play with settings to minimize the effect.
Second issue I had trouble with is elephant footing - tried every which way to get rid of that and in the end had to resort to chamfering the top and bottom layers.
third issue is differential shrinkage between filled area and solid top surfaces - there would be some shrinkage across the middle of the teeth relative to top and bottom cured to some extent by chamfering the top 3 or 4 layers.
if using PLA for gears, consider post print heat treating them ( soak at constant 60-70c for a couple of hours in thermo controlled oven). You will be amazed at how tough and heat resistant the gears become, but you will have to calibrate the shrinkage amount so you can size the print correctly to allow for, typically 3-5% reduction on the XY axis. if Z is important, then you may need to allow for 1-3% expansion. Depends on material, fill, thickness etc.
Having said that, eventually I have printed perfectly acceptable gears for the Myford and Minilathe that perform very well as screwcutting and feed gears. course they wont last as long as metal, but the ones I substituted on the minilathe driven off the metal tumbler pinion are showing no signs of distress after 9 months use and if I do break one I can just go print another!
Expect to print gears quite slowly with high fill and as many walls as you can manage to get a good tooth fill with a 50t MOD1 10mm gear taking about 2 to 3 hours to complete on the bed.
When using high fills and big gears, warping becomes an issue, so higher filament and bed temps needed which of course makes elephant footing worse.... and so it goes.
Edited By Martin of Wick on 30/12/2019 11:02:37
|Thread: Mini lathe amadeal cj18a help needed|
If the motor sounds as if it is running then it probably is OK. Check by taking of the backgear cover and look at the small pulley on the motor shaft.
Most likely the belt is not under sufficient tension and is slipping or the small motor pulley is loose on the motor shaft and needs the retaining grub screw tightening.
It is also possible that some teeth have been striped from the belt (if the lathe has had significant use, so give the belt a visual inspection.
Strongly suggest you take of the motor cover at the back of the lathe so all is easier to see and do a thorough inspection. Even if the issue is inadequate belt tension/alignment you will still need to do this to get at the adjusting screws and bolts etc.
If it is anything like mine was when it came out of the box, expect to find that you will need to completely re align and re tension the belt by adjusting the position of the motor with respect to the headstock. Expect this to take 2 or 3 hours of knuckle skinning frustration with small spanners and sockets and will probably need the front electronic control box removing to get at the motor lock bolts.
Unplug the lathe from the mains before proceeding.
|Thread: Replacement inverter advise|
I guess it all depends on your individual tolerance band on the risk/reward scale. The four legs good-two legs bad approach is not really very helpful.
I would expect anybody contemplating use of this type of equipment to do their research and understand how to program the critical safety parameters and use the device correctly. Regardless of source, these are not 'plug n play' devices.
It is true that there is practically no backup for these low cost VFDs and although documentation is available, it is far from comprehensive, so they may not suit a naïve user.
The OP appears to be familiar with VFDs and anyone can google XSY-AT1 for a sample 'manual' for that class of device (actually only a couple of sheets of A4). They can then decide whether the provided functionality and guidance for that device meets their operational requirement and is within their competence). A comparison can be made with the alternate range of 'branded' VFDs available. I am sure the vendor (if they are any good) would be willing to send a pdf of the 'instruction' sheet if asked.
I would certainly recommend for any VFD use that the unit is operated correctly and the correct manual for the device is used (normally the one supplied). Critical parameters should always be correctly set with respect to the safe use of the motor and safe operating requirements (eg. voltage ranges, over voltage protection, operation frequencies, max output currents, ramps, braking, motor poles/speed and input requirements). Some parameters may be testable prior to full operation.
I may have been exceptionally lucky, but I have not had any issues with these devices over the past two years, including running higher capacity inverters on low power motor. However, I do make sure to set the overcurrent (with reference to the motor plate) and other available parameters (response time) correctly. On the occasional lock up experienced, the inverter cut supply and faulted into the safe condition in one second.
It may be a false sense of security, but I feel much safer running a machine with even an unbranded Chinese VFD control than a single phase machine where the motor control is limited to the on-off switch.
I have purchased and used several (3) of this class of low cost inverter and always from the lowest cost UK re seller that I can find at the time on the Bay! These were a .45kW unit for a .25kW motor, a .75unit for a .35 kW motor and a 1.5 kW unit for a .75kW motor.
They have all worked perfectly out of the box. The instructions and programming guide supplied is basic but satisfactory. I am not an electrician but was able to work out the connection points for an external pendant for control as in on, off, speed, reverse, e-stop etc. In any case, there is a lot of info available on the web.
Programming is rather clunky but adequate for the limited range of functions available (adequate for most hobby users). These days, fully speced industrial units have about a gazillion weird and wonderful functions that are of little use to the hobby user, indeed some functions are so obscure that I cant even imagine what operation would even use them.
However, bear in mind these low cost strictly hobby devices are not intended for 24/7 industrial use and the limited software is one of the reasons they are affordable for the average poorboy (i.e. me!)
Agree with JB - get a unit that is at least twice the rating of your intended motor. Having said that, the only unit I found to become even slightly warm with extended use was the 1.5kW unit. If it ever fails (and there is no sign of any problems to date) for £55 or so I can replace it with a 2.2kW unit without tears.
In any case you might decide you would like a gruntier motor one day and the price differential on the larger units is not great so a larger unit future proofs you.
|Thread: Anyone know about buying freehold to a house in the north|
Understand your lease. If it one of the old 19c land leases that were bundled up into packages for sale to punters as a form of income, under current law the current owners of the lease have very little power - there may be covenants in the lease, but they usually unenforceable if deemed unreasonable (restrictions beyond the grave type arguments)
The issue with this type of lease is the lease owners have not been able to raise the ground rent by law. BUT that does not mean there haven't been attempts to get the current law overturned in the past and wouldn't try in future (although you can insure yourself against that risk).
Given the issues with modern leases on new estates, it is getting difficult to sell any type of leasehold house - all the punter hears is ' lease' without understanding the type of lease or the issues involved. Generally better to purchase the lease and convert the property to freehold if it can be done at a sensible price. In theory, the value of this type of lease should be negotiable between 10 and 50 times the ground rent. Supposedly, these type of leases were to be killed off by legislation by 2020 / 2021 along with chancel liabilities etc. Given the demonstrable lack of performance of our elected members, your lease will probably run out before that happens.
Ensure the person purporting to own the lease is the actual owner (have they registered it with the LR in their name) if not can they demonstrate their title to the satisfaction of a solicitor experience in land law and the Land Registry (easy to check using Land registry). In some cases, the purported owner does not have critical documentation and is not always able to prove title. In that case all bets are off unless the title holder can be located.
If you wish to proceed, take advice from and use an experienced solicitor which will double your costs, but you will have to weigh that against any benefit of converting the property to freehold.
|Thread: primus blowtorch|
these people have 'most evertin for pressure stoves lamps and torches etc
|Thread: Diamond wheel grade for T&C grinding|
I read through some of the past posts, and apart from a sideways reference to a hyper fine 1200 grit wheel, I could see no reference or discussion as to what practical grit sizes are in common use.
Bearing in mind I have managed quite well on quite coarsely ground tools, I cant imagine wanting to spend time on lapping anything to a nano finish. So was wondering whether there was any point to grit sizes beyond 120 for practical sharpening/touch up.
I don't know if EP discs can be cleaned or not. All I know is my diamond hand laps are getting clogged. not even sure if these are sintered or EP.
Am applying to the forum for some guidance...
For conventional grinding, I have always used a W36 to shape HSS tools and 60 or 80 grit to finish and recently a 60 green grit to shape/sharpen brazed carbide. Sometimes, a tool may get a final hone with an appropriate grade of slipstone. I use the usual budget style 3000 rpm grinder with a collection of various rests and guides etc.
This system has worked for me for a long time, but in order to move with the times, I was thinking of trying an EP diamond wheel (now they are affordable) to see if I could improve my efforts on the brazed carbide tools
So, my question is what would be appropriate grain sizes for EP diamond wheels for use on the hobby grinder ( was thinking of getting 80 and 120 grits for finish grinding). Is there any point going any finer?
Can you use the 40 grit ones for shaping, or does the abrasive just get ripped of the substrate on HSS?
Secondly, are the diamond impregnated resin wheels any better than EP diamond? Also, most of the affordable impregnated resin wheels seem to be in the fine range of 150 to 180 grit. Are these any use for sharpening, or are they only for final honing and polishing up of carbide inserts?
When they get clogged, how do you clean diamond wheels, ultrasonic cleaner, acid, some other method?
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