Member postings for Dave S

If 3/4” dual faced mdf flexes annoyingly on the current table I would suggest the current table is likely to be the issue.

Dave

Been quietly gathering parts and such for this, and I'm starting to build now.

I have scraped flat an old 14x12 surface plate, obtained a table and some steel to make the frame.

I have been thinking about arrangements more and Y with XZ is back as it produces a more compact and simpler (ish) machine to make.

However I dont understand why people put a Z slide on the X ways? Most homebrew builds seem to be like this, but its not a configuration you see in high precision full sized machines.

The nearest I see is planers - where the tool slide is sometimes on the X ways, but if you look at Jig borers they often have z ways on the columns and x on the bridge.

Compromises I can see for this configuration are 2 leadscrews and more difficult alignment of the Z ways, but pulses are less spindle overhang and a more rigid arrangement (i think) You also only need spindle power to the movement - the steppers are all located at the machines edge.

Thoughts welcomed. I'm starting to build the columns this week, and either arrangement is still possible.

Dave

Nicely put

Dave

MSC often have reasonable endmills in their monthly Advantage flyers.

Carbide is an oft abused term… In days of yore carbides had relatively large grain sizes and negative geometry was the order of the day. These cutters are indeed not ideal for lighter weight/lower rigidity machines. They’re also not usual in 10mm or less diameter.

Compare with today’s solid carbide micro grain mills - super sharp, stiffer than HSS and not unreasonable in price.

I would have no qualms about using solid micro grain carbide on a light mill - that’s pretty much all I run on the proxxon.

I tend to use a mix of HSS, insert and solid carbide, mostly depending on what size I need on the other mill. My mill is big and heavy, but apart from the insert stuff ( which tends to be larger) the mills are generally held in ER16 collets, so of the size a SX2 would use.

Dave

The second one appears to be a “cutaway” teaching model to show how the displacer and linkage run inside a Stirling engine.
I expect the 2 alloy parts move in a sequence where one lags the other?

Dave

I would suggest you look at a Maun Safety Rule: Maun rule

Dave

Looks a lot like the pattern on retro reflective things - like the reflectors on cycles.

Maybe some clues there for how to

Dave

I use meths as it’s what I usually have to hand

Dave

A skilful bloke with plenty of practice time in.
Not sure how that’s relevant to machine hacksaws or controlled depth of cut tho?

How is limit the depth of cut different to cut depth is consistent and controlled?

Finer toothed - yes the gullet is smaller and fills, but courser toothed the gullet is potentially deeper than the material thickness - so if you can control the DOC such that you don't take too deep a cut what disadvantage does it bring?

In extremity a shaper is a power hacksaw with a single toothed blade (especially if you squint a bit )

Hand saws are poorly guided in comparison to machine saws.

Dave

I was thinking about the rule of thumb - 3 teeth is presumably to limit the depth of cut - so you don't end up trying to take a full tooth gullet depth cut in a thin material - thus bending the fragile edge rather than cutting it, or creating a load on the saw that is too high to push through the material.

I think this certainly applies for human powered saws - no doubt many of us have at some point tried to use a too course blade in a hacksaw (or in my case more often a jewellers saw).

My power hacksaw however has a defined depth of cut setting - the blade is fed down by a certain amount on each stroke. I rarely alter the feed setting - but then Im usually cutting the same sort or big chunks of stock.

Point is that if the hacksaw has a feed setting ( and not just a gravity weight) you can probably successfully use a courser blade than might be suggested otherwise.

Thoughts?

Dave

Mine had gaskets as I remember having to find the gasket paper to make new ones.

Ill see if I have any photos for where they go - IIRC I didn’t pay attention, and made them for the wrong face initially…

Dave

I made my scraping deburring stone from a old chunk of dual grit oilstone in an afternoon with a diamond “drone” much like the one Ketan sells. Might even have been one from there, but numerous suppliers have them.

Took an afternoon because this was a well used and consequently quite “hollowed” from axe sharpening.

Dave

Missing some important information (remind you of anyone?)

The sheet is 1mm thick and needs 0.75 radius, but for how long? Cutting a radius on an edge 3mm long is different to one 30mm or 300mm

In rubber - how accurately?

Its 3/4 of the thickness, so nothing like the initial sketch.

Something like this would usually be moulded in, especially in a very soft rubber.

what’s the back depth - could an o ring profile be substituted.

I suspect the details to help will be “secret” as it’s a bookbinding invention…

Dave

Evening all,

I see that there are now both open loop and closed loop stepper motor drivers are easily available.

Obviously there is a price difference. Is there a good reason to choose the closed loop ones?

Im not sure what size motors I need, but based on what Seig have put in the KX1 and KX3 I’m going to go for about 3NM in a Nema23 frame. My build is not as large travels, but quite chunky bits of steel. That puts something like £100 - £150 difference for closed vs open loop, based on poking around eBay and Amazon for pricing.

I have 1204 ball screws, and hiwin carriages, saddle is 400mm x200mm channel steel, table 200x200 x20 steel, all day on a cast iron surface plate as the base.

Dave

A FNK25. Bought it on eBay for £600 a good few years ago. It was somewhat larger that I intended, but I’m very attached to it now.

The size is really useful sometimes, but it’s also sensitive enough to drill sub 1mm holes and use 2mm carbide cutters. It makes an excellent tapping stand - done a fair number of M1.6 threads with it.

This was during the making of a stainless steel watch case for my daughter. If you look closely you can see the tiny cutter.
I can’t figure out how to make the pictures the right way up.

Dave

Not directly comparable but my TOS has a top speed of 4500 and I often use it.
Dave

I lifted mine with a block and tackle attached to the t slots, then strapped it out of the way.

a picture in this thread: **LINK**

Dont forget to release the ram ends from the table. I think they sit in a u slot, so just releasing the nuts allows the table to lift.

Dave

The tariff code just tells you what the thing is. There are associated tariffs depending on the country of origin.

If the micrometer is directly imported from China its 2.7% tariff. China to france micrometer import

If its imported from China to the UK and then exported it still has a country of origin of China, and so 2.7% applies.

If a micrometer is made in the UK then its origin is UK and the FTA preferential rate of 0% applies (although you still have to do a load of paperwork which wasn't the case prior brexit - that is the none tariff barrier that actually costs money).

A set of bits to make a micrometer from China which require 'sufficient' work to make them into a functional micrometer can qualify as UK origin, and hence 0% tariff

<Avoiding semi political rant about the costs of brexit here>

Dave

Micrometers are 90 17 30

Spokeshaves and Hand Planes are probably 82 08 20 - Tools, implements, cutlery, spoons and forks, of base metal; parts thereof of base metal - Knives and cutting blades, for machines or for mechanical appliances - For woodworking

The EU Access2Markets site is pretty good for finding the HS tariff codes. : https://trade.ec.europa.eu/access-to-markets/en/results?product=820820&origin=GB&destination=FR

Dave