Here is a list of all the postings Will Bells has made in our forums. Click on a thread name to jump to the thread.
|Thread: Parting Off MEW225|
Neil - yes I made a sprung tool for front parting.
When my only lathe was a Myford, parting was a slow affair and every now and then the tool would snag, usually causing the belt to slip (I tended to leave it fairly loose on purpose), but rarely causing more than annoyance.
When I got myself a bigger lathe with a 1.5HP motor, snagging also happened occasionally with deep grooves (say 10mm plus cut depth) but the resulting smashed tool was much less fun. The cross slide was not slotted to take a rear tool post so I became paranoid about parting and would avoid it like the plague.
Logically slideways must have clearance in be able to move, and logically I would expect movement downwards, towards the the flats (on which the top or cross slides presumably normally rests) to have much more stability than pulling upwards where there is clearance and also a wedge effect. In short, just looking at the geometry of the top slide alone, I decided that the tool would certainly move down and pivot inwards, towards the work, when loaded.
So I made a spring loaded tool holder that held a normal HSS parting blade and pivoted away from the work under load which greatly improved things. Basically, it doesn't prevent the occasional snagging, where swarf wedges itself at the side of the parting tool, but it improved the consequences no end. So instead of smashing things, it moved out of the way and cleared itself or at least allowed time to back off the cut.
But in all honestly, now I use a carbide parting tool, I rarely have an problem with snagging anyway, so the sprung holder is not used very often. The Carbide cutting edge is wider than the rest of the holder, which I couldn't achieve with the HSS over much length, and the tip is shaped to reduce the swarf width, which I couldn't manage at all.
So now I part at a high speed and use a constant dribble of cutting oil in the slot, dispensed from a syringe. I also normally keep the top slide locked, which I suspect helps as well.
Cheers - Will
|Thread: Suds Thief|
Hi Bazle - about half a bucket load of fine chips over the last month. All pretty dry now, but yes it was probably wettish when I cleared it.
I don't have a dehumidier but I do keep the workshop warmish, i suppose about 18 to 20 degs around the clock but only heated by a 600w oil filled radiator.
I didn't think about the loss like that Les and no, the mill is running off a single 240v plug so it's not taking that much energy - I'm able to play again today so I will measure exactly what happens.
Cheers - Will
OK people, who's syphoning off my suds ?
I have been playing with my newly rebuilt CNC mill, cutting aluminium and generally enjoying myself when suddenly I find that the soluble oil coolant in the (20 litre) reservoir has started to foam and has disappeared, or at least halved.
What's going on ? I expected it to last months, but within a few hours of use it has lost probably 5 litres.
There are no puddles of coolant on the floor and no evidence of condensation or a damp workshop. But the logic is it's evaporating at a heck of a rate.
Is this normal ??
Help, Will B
|Thread: Temporary loctite for drilling|
Yes, it works - I often use super glue to hold things together for drilling, light milling etc.
The bond is easily broken afterwards by heat (250 degs) or sometimes a sharp hammer blow.
You will have to clean the adhesive off afterwards though.
|Thread: What did you do today? (2014)|
Yep, oil filled radiator was switched on last Wednesday in readiness. Bit of a wimp, I know !!!
|Thread: Milling Machine Trammel|
Yes you are right, tilting the head a gnats ensures that the cutter cuts on the leading edge only so that the trailing edge doesn't touch and spoil the surface finish.
I do sometimes do this but most of the time I keep the head square because setting work up setting up, for example with an edge finder is then not accurate and drilling holes, especially deep ones can be a problem.
The problem with trammels, or anything else that fits in the chuck, is that they are limited in accuracy by the chuck. And my drill chucks can easily be a couple of thou out (try bunging a 6 inch silver steel bar in it and see what the run out is at the end) and different every time it's re-chucked.
No, I'm an old fashioned bloke - I use a nice chunky bar to hold the dial gauge and proceed just like Tony, but without even the ground flat, just take the reading straight from the bed. If the dial gauge is rigidly held, the plunger can easily be lifted off the bed then rotated by twisting the chuck without changing the setting.
But I did see that the toolmakers at our works use trammels and I suppose they should know, although it may just be to avoid the aching neck ......
|Thread: Which plastic to use.|
That's an excellent comparison. It's bookmarked !
Delrin is a type of Acetal from Dupont. I think slightly better strength and doesn't squeak as easily but slightly worse temperature and chemical resistance on average. But for Peters application it would be as good as anything. And bog standard acetal would be good as well.
Isn't PEEK normally very stiff but can be quite brittle ? I think it's the wrong material to use in this instance as the flanges are thin and I would expect them to break off after a short time of use.
You are right about nylon being hygroscopic, which is why I doubt it would be used in original parts, but in reality the only real downside is that it causes a dimensional change and they actually get tougher and practically I'm sure they would be OK.
PEEK is also hygroscopic if I recall correctly.
Cheers - Will
The answer to your material question is almost certainly Acetal. There are some grades that are better than others, but I'd take a chance on the bog standard stuff.
Acetal has no problem with hot water and will be OK with the drying temperature.
Cheers - Will
|Thread: 'average model engineer'|
Luxury - Ah dug t'ore owt ground an' smelted it ont' stove ............
Just off to play with my CNC and avoid the car park
Cheers - Will
Frankly, I don't care how anyone involved in our hobby makes the call between money and time. Why should any of us - it's a personal choice as to how to spend our spare time.
As one of what seems like a dying breed in this country sometimes, an engineer making his living in a real engineering vocation, I am simply grateful that people of all walks of life have an interest in engineering of any sort !!
Cheers - Will
|Thread: Chinese CNC Spindles ?|
Just to finish off....... the spindle ran properly today under computer control with success.
It's plumbed in and squared up as accurately as I could.
The spindle works well and ran for a couple of hours without load to run it in without any increase in temperature at all. I cut a couple of shapes in plastic then a profile in aluminium with a 1.5mm cutter - cutting speed too slow on first attempt, but turned the wick up to 15k RPM and the finish and accuracy was spot on.
So, I'm now a very happy bunny !!
Finishing an air curtain for it now and need to seal a couple of areas for the cutting fluid and it's ready to go
Cheers - Will
|Thread: My new best friend.|
Thanks Nick ..... ordered !!!
That looks very interesting .......... I'd like to try that, where did you get it ?
|Thread: Elliott Progress Drill Press - dismantling.|
I've just had a look at mine - yes boss comes off. Its is pinned with a single 1/4" pin through the boss and shaft. Mine is a straight pin through both sides of the boss.
The shaft is about 3/4" diameter under the boss and the pin hole is drilled 15mm from the end of the boss. The pin is alighned with one of the holes for the arms. May help find it.
looking at mine there is no way that the pinion and shaft will come apart any other way but from tapping out from that side
good luck !!! Will
I have a progress 3 which is geared ( is yours ?) but it looks similar. I can get into the workshop tomorrow morning and check that one for you and see if I can help further.
I have had it to bits in the past so it should be obvious once I look at it again.
What about taking the boss off the other side (probably pinned in place through the boss and shaft) and gently tapping from the other side. I'dbe surprised if wellying was required.
Looks to me that the pinion will come out of the bore with the bearing - but the other side looks a bit smaller than that.
Cheers - Will
|Thread: Drill Press Options|
Hi John - I have used a few Fobcos in my time and I have owned a Progress 3 for many, many years. Both excellent machines and built to last. The Elliot is used as much as any machine and just keeps on going.
But putting aside the difficulty of fine down feed, even light milling is never going to be very satisfactory for you. If you want to do anything other than play, I would not contemplate it.
How do I know ..... yep, I tried very hard to get the Elliot to do the same thing when I was a lot younger and dafter. Among other desperate things I modified the spindle and made a chuck to safely hold the cutters for it. In fact I even ended up making a frame that bolted to the wall in an attempt to stop the vibrations. Perhaps my expectations were too great, but I saved up and bought a cheap mill.
Drill presses are made to be strong in the vertical direction, but they have much less rigidity in the lateral direction, which is where most milling forces are.
Milling in the lathe is a lot, lot better because of the stiffness, which is why vertical slides were very popular back in the days when cheap far eastern machines were unheard of.
Good luck though whichever route you choose - Will
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.