Fixing the Mini Lathe Saddle - Down the rabbit hole

Fixing the Mini Lathe Saddle - Down the rabbit hole - Part 3

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Күн бұрын

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@patrickdewhirst8125 2 ай бұрын

Hi love these three videos , the tube of engineering blue, takes me back fifty years, where as apprentices we put just a drop on the office door handle, and watched the mayhem, there was hell to pay, the whole office block had to be redecorated, Thank you for the memory .. And Oh I have loved these three videos .

@radboogie 2 ай бұрын

Thanks Patrick, glad you enjoyed them! Great story about the engineers blue, always love to hear apprentice stories 👍

@tdematteo01 Ай бұрын

Richard, this is great. I am getting ready to attempt my first scraping. Thanks for the great video.

@radboogie Ай бұрын

@@tdematteo01You're welcome, good luck with the scraping 👍

@davidt8438 6 ай бұрын

What a shame. With a little more care and attention these mini lathes would be providing thousands (maybe tens of thousands) of people countless hours of fun, productivity and enjoyment. But the word is out that they’re trouble. Even armed with knowledge, skill and the right tools it’s a time consuming job that is frustrating at the very least. Imagine how many people simply don’t get into machinery work because they can’t start small and build their skills. These mini lathe machines should come in a complete kit form except that they should be machined to closer tolerances. It would probably cost the company the same amount to machine it correctly and just not assemble it. They win and we would certainly win. Most people who buy machines like this don’t mind fine tuning them but almost nobody wants to have to machine their own parts and rebuild them just to see if the hobby will lead to more. My hats off to you for your patience and persistence in going through this process.

@radboogie 6 ай бұрын

Thanks David, I totally agree. I was lucky enough to be trained in a machine shop during my apprenticeship so I'm happy to fix any problems that I find, but as you say for the newcomers looking to pick up the skills on their own these lathes are a setback for them. I don't think all of the lathes are terrible, and it probably pays to buy one from a brand such as Clarke or Warco here in the UK. At least that way there will be a warranty and I'd like to think that if they are putting their names to the machines they would do more QA than the unknown brands.

@johnrussell6620 9 ай бұрын

At 5:00 your word "SPINNING" is actually called "HINGING" by professional scrapers. Just thought you would like to know. Thanks for taking the time to make this presentation.

@barryshrives 9 ай бұрын

I’ve had the same problem with the saddle binding the cure is to scrape the underside off the ways as they are not consistent with each other on both the front & back ways

@darkwinter7395 9 ай бұрын

I currently have one of mine (the one that's not getting a CNC conversion) in pieces for just such a rabbit-hole-dive... also going to hang a DRO (a "real" one with linear scales) off of it.

@radboogie 9 ай бұрын

Good luck with it mate - DRO will be a great mod 👍

@zooki4x4. 4 ай бұрын

The cheap machining of the ways is the problem. The underside was milled and left rough. Flipping the lathe over, with the saddle removed, draw file the bottom in the tight spots to even up the thickness and it should clear.

@pulidoggy 7 ай бұрын

Hello Richard, I'm following with interest your enlightening videos, and trying to follow your tips in order to better tune my mini lathe, so I'll take the freedom to ask your advice from time to time, hoping not to bother you too much 😊 A couple of questions, then... First, is your scraping tool homemade or else is a commercial product? I'm asking this because at the hardware stores I asked for (I'm from Italy) they gave me weird looks 😆 Maybe it is not such a common tool? And second, I noticed that someone around is suggesting brass as gib material... What is your opinion on that matter? Thanks so much! Roberto

@radboogie 7 ай бұрын

Good to see you again Roberto! Feel free to ask as much as you want, the purpose of my channel is for people to share what they know 👍 Engineering hand scrapers are hard to find these days, not many people sell them. Mine was purchased from a KZbinr named "Impractical Engineer" - he makes and sells the scrapers on eBay - www.ebay.co.uk/itm/334369762367. You can also try to search for Sandvik Coromant 620-20 though these are also hard to find. www.sandvik.coromant.com/en-us/product-details?c=620-20%20%20%20%20%20%20%20%20%20%20%20%20%20%20H10 Alternatively you could grind a scraper from an old file. 60mm radius on the end, 5 degree negative rake (95 degree blade angle). Brass can be used for gib strips though I would prefer phosphor bronze. Cast iron gibs seem to be popular, as it has excellent sliding characteristics with itself. I plan to make some new gibs with phosphor bronze in the future, will probably cut them from hexagon bar as that way two of the sides will already be the correct angle.

@pulidoggy 7 ай бұрын

@@radboogie Thank you Richard! Only, I'm not sure to understand the advantage of using an hexagon bar as starting shape (my fault... 😊) Being the cross slide gibs shaped as four-sided parallelograms (if I see them right), then is the hexagon choice a way to get precisely 120°/60° angled gibs, or else just a way to start with two surely parallel opposite sides, (that could be obtained also from a square/rectangular stock) and then work them to the desired (arbitrary) final angle? Pardon me for possibly naive questions, but I'm into turning just for four days 😬 A long way to go...

@radboogie 7 ай бұрын

Using hexagon bar is just my idea of being able to start with two sides at the correct angle. When I make new gibs I will be making them with hand tools (no milling machine) so if I saw a strip of hex bar leaving two sides at 60 degrees to each other, I can then file the opposite faces to be parallel with them and verify on my surface plate for parallelism. As I say, just an idea I had to improvise with hand tools.

@rayflowers9097 9 ай бұрын

Ok I'm legitimately invited now.

@mk6595 8 ай бұрын

How do you ensure that the scraping won't raise burrs that interfere with bluing?

@radboogie 8 ай бұрын

You go over it with a fine stone and a bit of mineral spirit after scraping.

@TerryClarkAccordioncrazy 3 ай бұрын

From what I see, the minilathe consists of a roughly machined set of parts which the customer can use at a basic level or refine to create something better

@radboogie 3 ай бұрын

That sums it up well. There's actually a decent little lathe in there waiting to get out.

@stephaniea9722 9 ай бұрын

You're going to want a straight edge to measure against each face, and find a reference face that is actually straight. (We're not talking about a ruler, but a precision flat and long edge). Most hobbyists make their own. From there you'll need to make that reference surface as flat as you can. After that, you'll need to start measuring against the other surfaces and make them parallel to the reference surface. It's a ton of work but there's really no way to cheat around it. Here's a good video on what you'll need to do kzbin.info/www/bejne/bX63eYqriJqGbqMfeature=shared You'll want to think long and hard and the order of operations here, as doing things out of order will mean more work. My suggestion would be to scrape the top of the ways flat first, that'll be your reference. Then scrape the underside of the ways flat and parallel to the top. Use a surface gauge and some blocks to prop the bed up to get your measurements on how to correct the angle. Then measure the V ways using a similar cylindrical V block and determine how to correct their angle and scrape them parallel. (Side note, mark a point on the V cylinder so you're always measuring to the same reference, and cut a relief inside the V cylinder instead of scraping all of it - you only need 4 points of contact. In fact you can even use a bit of pipe instead of a solid round bar.) Considering that none of the ways are hardened, don't put too much effort into it as they're sure to wear. It also might be worth it to anneal the entire casting as they're likely not stress relieved either. Some time in the oven at the correct temperature will do it, but if it's in your kitchen you would probably want to clean and remove all the paint first else your cookies will never taste the same again. Also, make sure you buy a big box of tea first, because it's sure to take a while.

@radboogie 9 ай бұрын

Did someone say "Tea"?

@deekthefirst 4 ай бұрын

Where can I buy a decent scraper?

@radboogie 4 ай бұрын

I got mine from Impractical Machinist off eBay www.ebay.co.uk/itm/334369762367 he also has a KZbin channel which is well worth checking out. Alternately you can try to find a Sandvik Coromant 620-20H10

@mikemelbrooks 9 ай бұрын

I think i would try cutting a long bar and check for taper. It might give you a clue as to wether the front way is parallel to the chuck. I dont mean to tell you how to suck eggs.

@radboogie 9 ай бұрын

Thanks for the suggestion Mike 👍

@jonbruford7950 4 ай бұрын

hmmmm... it's such a garbage way to hold the saddle on, 6 bolts and 4 grubscrews to adjust (which one needs to change, and which way should it go) and none of them easy to access... my solution is to chuck those lumps of cast in the bin and make tapered brass gibbs. it's a bit fiddly but so much easier to adjust. (assumes a milling machine is available) that said, nice bit of scraping :-)

@radboogie 4 ай бұрын

Yes, and the grub screws cause the iron gibs to bend if you over-tighten the nuts. Tapered brass gibs would be great, might be a job for when I get a mill 👍

@jonbruford7950 4 ай бұрын

@@radboogieI got the idea from rotarySMP channel. pimping the minilathe series. fettling the beast from the ground up