Member postings for Russ B

As for the euro standard cutters, you can make your own from gauge plate and heat treat - I guess a single cutting edge would be fine. I'd balance the cutter with counter weights secured to the unused blade slot or it'll probably start to walk around the shop.......

If you need a dust extractor I have a brand new 1hp 3PH Siemens side channel exhauster and a load of 2" vac hose, free to you next time your passing. You'd have to keep the blower clean, so it would need to be an enclosed filter with the blower on the clean side. I was thinking two steel drums with a manifold made from two lids and a tangential inlet, one detachable to catch the fall out below, and one above with an internal 1/2" cage, 1/2" from the drum, so the filter material gets sucked up into the cage. You can buy the filter material on a roll cheap and add a sewing machine to your workshop skill set!

The only snag I can see would be the side channel type blowers tend to be more about creating pressure than moving volumes of air, so I'd have to check the velocity in a 2" pipe is high enough to carry wood chips (known as the interstitial velocity) but I have stacks of data on these values for a wealth of different material and particle size distributions. If it can't move the chip, the solution is a smaller diameter hose to increase velocity, we could make it work!

Ensure the adjusting the screw is properly set and locked, locking was hit and miss on mine, I ended up cleaning it out with solvent and applying thread lock.

Also if you feel a notch, check the actuating shaft for damage, the ramp on mine was damaged, a thin layer of hard face weld, dressed with an angle grinder and polished with a stone provides a lasting solution without having to remake the shaft. It's a tricky weld as you don't want too much heat in the small shaft, but too low a voltage will give an undesired convex bead, making dressing it back harder, but it's not beyond the amateur. I'd practice on a piece of round bar first. I never fixed mine in the end, it was still usable but force required was becoming (very) excessive. I planned to use a dremel tool to make a vee notch up the centre of the ramp, on the actuating shaft, 1/2 to 2/3 the total width, and then use the remaining edges right and left as a reference to dress the hard face flat with diamond stones.

Yes, he's back on again this Sunday for another interesting program.

Neil, you missed "if your lucky" inbetween the words quill and column..........and you also just assumed the spindle is running true inside the quill........

Check the 360 saddle is true on the XZ plane, as described (or by any other means) if this is true to the XZ plane (aka front face of the column) - move on and check the quill is parallel by extending it, and mounting a dti on the column and then run the milling head up and down dialing in the column left to right (nice and easy its a rotating head after all) but also front to back (hand scraping or machining required - not so easy!!) 

once you've got or know the quill is true to the column in the XZ plane and XY plane as above, and you know you're 360 face is also true, only then can you start making assumptions as bold as suggesting the spindle, inside the quill, the mating between the quill and 360 face, and the mating between the face of the 360 and dovetail attaching it the column are ALL in alignment....... and you're still not 100% because you've still not check that the spindle inside the quill is running true, and this is where rollies dads method comes in to play.

For the record, my 360 face was ok on the vertical saddle, but the spindle was out of alignment. I went for the quick option as you suggest here Neil and it came back to bit me, every time I moved the Z axis, I drifted off the X,Y co-ordinate because I'd assumed my quill, and the spindle inside that quill were both true to the column - silly silly mistake. The spindle inside the quill was slighty out, but no big drama, the quill however was pointing towards the column! So if I shimmed the column to get the spindle level to the table, the Y co-ordinate would drift as I wound the head up and down.

Check all this once, and use the machine for life, and take neat little shortcuts as you suggest, with confidence.

Edited By Russ B on 13/11/2017 13:04:58

I just editied that to add a missing step, so if you've just read it, and this post wasn't already underneath, I apologise the edit started 2/3rds of the way down.....

I might have to edit it again, but it's now Friday beer'o'clock on my side of the world - and since its 34c and blazing sunny, I'm off to slap on some sun cream and head to the beer garden !!

Sorry if this a bit pushy, but here's what I'd do and indeed what I did on my own BF-20..... it's not a quick fix, but it's a good thing to know.

Tram the tilting head to the table with a dti, to ensure she's not rotated left to right.

Tram it front to back, to see if she's tilting forwards or backwards.

Great, lets, say it's perfectly square - you now have two useless pieces of information, relative only to an arbitrary reference because you've assumed your dovetail column is perpendicular in two planes AND you've assumed the rotating circular surface of the vertical saddle is also square in two planes....... (or you used an engineers square, and assumed or accept the inaccuracy of your square/surfaces/measurements) - often with machines of far eastern origin, if they're not square at every step of the way and they don't mind. They just grind a bit off (usually off one single bit) here and there to get the final figures - as soon as your start raising and lowering the head, or rotating the mill head, you're assuming things move square and true, and they probably dont.

Best not to assume anything these days.

so let's go back a step and try to derive accuracy, assuming only reasonable things. Remove the table from the equation, forget it exists for now, so dont worry about that bolted connection . You now have a column, a saddle with a 360 degree surface, and a spindle axis. Its not unreasonable to assume your column dovetail was machined in a single pass and is pretty much square and true, if you've got a micrometer you could check it's parallel, but I don't think you'll gain much.

Imagine now, that this column is laid down in front of you, with the spindle box on the left, as a lathe would be setout. (forget the table exists, remove it from your imagination). Now, you have a lathe without a saddle for a tool post, but who's spindle box can rotate on its own saddle.

To check this rotating face is parallel in two planes, isn't easy, since right and left, you have no column, no reference, and probably isn't necessary unless you're attempting to split the atom in your shed (it's been done.....) but you can check it in one plane ((THIS IS OPTIONAL, NICE TO KNOW KINDA THING)), along the axis of the column. Simply move the saddle to centre, and mount a DTI in the spindle. Rotate the spindle box 360 degrees, taking 4 measurements as you pass the lower face of each dovetail - making sure you don't move the guage.

assuming you're 360 saddle is true..... move on.

now check out rollies dads method of spindle alignment, you can adjust very easily to align it towards or away from you (imagining it's laid down like a lathe) - however if you're spindle is pointing up or down along the axis of the "bed" (again, imagining its a lathe) - this is a more serious issue, it means the alignment of the quill bore, is knackered - the only option is to remachine the circular face on the back to correct the up/down movement - if it's out in the other plane.... it doesn't actually matter that much (imagine it being mounted on a hinge like a door, opening and closing, it doesn't matter where it swings, so long at it's not dropping or lifting along the axis of the column......)

still with me?

no, me neither.........

so if you successfully determined that your 360 rotating face, is square, and you've determined that your quill isn't pointing towards or away from column, then you can now go back to square one (almost)

"Tram the tilting head to the table with a dti, to ensure she's not rotated left to right.

Tram it front to back, to see if she's tilting forwards or backwards."

You can't tram left and right to the table, because you don't know if your spindle is aligned to the column unless you've just done the rollies dads method to alight the spindle left/right. So now when assuming you've done that, when you "Tram the tilting head to the table with a dti, to ensure she's not rotated left to right." - the difference is - if you're out, it's the column that's out, and not any errors in the alignment of the rotating spindle box or the trueness of the 360deg spinning face.

The only accuracy you're accepting, is the spindle runnout - which can easily be quantified - you actually already have all the measurements you needed to know from the rollies dads method, so you can acutally offset then values and incorporate this - but seriously, this is getting silly, but its there if you want perfection, 

I'd consider that a mechanical QED (almost)..... now, if you still need that shim, you know you're not offsetting an error in your spindle to column alignment.........

that was taxing....... I'd started writing an article for the magazine but I'm a long way from home right now, so don't have it.... this is all off the top of my head, but I think this is right, I spent quite a while working this out - the measurement and checks are actually simple in the end if you think about it........

Edited By Russ B on 10/11/2017 08:18:56

I've enjoyed following this thread.

I think the lack of availability of scraping tools and consumables is perhaps a contributing factor to the decline of the skill??

Could someone give Ketan a nudge at Arc, it would be good to get some red/blue Volkcorp Canode in stock, and perhaps a small section dedicated to hand scraping bits and pieces!

+1 Andy, great idea!

I've just got my ER40 Sq.+Hex set!

I've bought things in the past that I thought was going to be handy..... and it really just didn't fulfil that expectation.

The more I do and see people doing with the these blocks, the more I like it!

I've added a pair of 20-40-80 + 10-20-40 Stevenson’s blocks to my Xmas list as I've always fancied a set and they'll prove invaluable for a couple of checks I want to make on my lathe next year.

Edited By Russ B on 07/11/2017 05:25:14

I got a mini lathe for this reason, I removed the back guard and drip tray, and slide off tailstock and then it's not too much trouble to slide it away under my bench when not in use. I've not stripped and checked it, but it turns acceptable/good parts out of the box - I can't complain.

This reminds me....... my main powder extinguisher's lost pressure.

Where (assuming you do) do you take these extinguishers to get checked and filled. It's a modern, good quality extinguisher with refill port etc, not a cheap jobbie

Exactly my point. The white metal bearings are no longer available, so I'd crunch a few numbers to get a feel for what's sensible, but all dependant on the oil feed, and I would consider the oil cups on the ML7 to be extremely effective. Also oils theses days have some very advanced additives so I'd expect them to outperform the kinds of oils available 70+ years ago when these were designed - by 25% maybe? I'm a long way from home so cant pull out any figures from texts but I'm sure it's in many of the old school engineering encyclopedias.

All this talk of speeds and motors is near irrelevant if you ask me. The answer is, however fast you like - change your pulleys and shoot for 10,000rpm!!

Or not....... because you'll melt your spindle to your bearings, and this is really the limiting factor, nothing to do with which motor you've gone for, you can always change a motor, you'll probably be able to pick one up from a junk sale for a fiver as a spare just in case.

You need to identify if you're running the original white metal bearings and soft spindle, or the newer bronze type bearings with a hardened spindle, then look up the maximum surface speed for your bearing material, and measure the size of your bearing and take it from there, if you think you think you can hit 2000rpm I'd say gear for it with your VFD at 100%, and I'm sure an occasional blast to 120% won't hurt anything, adjust your driver or driven pulley size to suit and make sure you're oil cups are working well (although I think these run significantly more oil than is required anyway, it was slightly comforting to see it pooling on the drip tray... oil cooled bearings would be a more accurate description of my old setup!

If you're near or passing Doncaster, let me know.

I have used "Durafix" to great effect and would recommend it for dissimilar metal too (copper to aluminium, no flux needed, no problem)

You need a lot of heat, anything sub 0.7mm, and you'd probably melt it unless you've got excessive amounts of "the knack"

Edited By Russ B on 01/11/2017 03:57:59

Well bloody hell..... I think Michael Gilligan has just flashed up half of what I was rambling about while I was typing!!!!

Good stuff there in 1.23 and it will easily fit with many other standard calcs surrounding belts

(and just look how much simpler rads make the equation!)

Edited By Russ B on 29/10/2017 01:03:05

sadly I'm 7000 miles from my notes at the minute but I don't do it like this....

I calculate the contact angle overlap on each pulley first (in radians if I recal correct) (if the pulleys are equal the formula should equal zero) - so if one pulley is larger, it's contact will be 1(pi)r+overlap arc, and the small pulley will be 1(pi)r-overlap arc.

As far as I know, this is the normal/standard way to calculate belt length (or pitch length at least) because it also gives you everything you need to calculate the torque that can be transmitted with a known tension (not totally applicable for toothed, but still needs to be done) and simple manipulation can tell you how tight the belt would need to be to transmit "x" amount of torque - it also tells you what the tension in the taut side will be, which will be a limiting factor (since you don't want to stretch or snap your belt! - hence the calc still needs to be done for a toothed belt, although it can be shortcut, but the next point would alter the tension because....

you can also easily apply inertial forces to the equasion as the belt tries to throw itself off the pulley.

you can then start manipulating the figures to see how much pulley overlap is required to transmit the torque you desire (for a flat or vee belt etc) which gives you an idea of where your idler needs to be to create the desired overlap.

for a toothed pulley, you'd just drop the friction factor our of the maxiumum torque calcs and assume it's 1:1 with no slip, and just concern yourself with the tension in the taut side to make sure you're not going to snap it. Since you don't have any slippage, adding an idler won't change the results, but common sense tells you need a certain minimum number of teeth engaged and the manufacturer or standard texts will probably dictate a minimum radius anyway.

has it been considered that many common toothed pulleys have inherent backlash - and there are a few which specifically dont - hence ideal of automation/cnc

- Sorry I can't give you proper formula - I've googled but didn't find what I need, I've seen other ways but they make it look complex...... see here for the closest but note, because he's using degree's and not radians, i think.... his calcs are significantly more complex/long hand with some slightly more exotic trig functions that im not entirely sure are necessary!

I should add, it’s nothing that can’t be worked/engineered to a satisfying solution - but I don’t think the extra agility or Z height is really worth the hassle!

Speaking from experience, Delta printers throw up more challenges for the mind and wallet - for little benefit.

Mainly freeplay/backlash in the Delta arms

Machines that make use of universal joints aren’t very clever.

It’s much harder to accurately calibrate your z axis - since you basically have 3.

Trickyness all round - agile, but tricky...

Yes.... they're quite a few quid, but better than an Ultimaker or the likes (which are £3k upwards!)

If you just want to 3D print very accurate models, without needing any skill or knowledge of 3D printing or computers, it's basically ideal, quick, reliable, easy - and if you want to tweak it, go for it, it's completely configurable via "expert" tick box in settings which opens up a wealth of menus and settings if you feel like killing a few hours.

I still have an i3