Great build Paul, you are becoming quite a toolmaker! A tip on the annealing of that part, I know you wanted the small area to soften, but you should heat the whole part evenly 450-550F then bring up the end to non mag. Prevents distortion, internal stresses, CRACKS , slows cooling, and all sorts of bad metalurgy... glad it worked out well for you.
Hi Al, thanks for your sound advice. A small heat treatment oven is on my wish list but I'm put off by the price. Need to find something scruffy I can restore. Cheers Paul
For anealling appropriate a decent size biscuit tin (metal) fill it full of nice clean DRY sand bury you hot pieces in the sand and cover with a couple of inches of sand and you have a nice cooling set up - vermiculite also works well
Hi Paul, that was a well hardened adapter does make you wonder why they didn't check the taper before hardening. Interesting to see how little apparent force springs the clutch. Great video and a useful piece to have in your collection. Have agreat weekend!!
Hi David, it's like the best safety feature. You don't even notice it saved your life (well the life of your screw cutting gearbox anyway). My lathe has steel gears but others have plastic and they can strip easily. Cheers
I had the clutch apart Kev when I was servicing and painting the lathe and the spring is very strong, so I was surprised it did not take a lot of force to get it to slip (lucky for me). Cheers
Hi Matt, I should probably take it a step further with more of an enclosure. Work in progress .... in the 'world of heat treatment'. Always something to learn. Cheers.
I think that jobber drills (or jobber-length drills) are for general purpose drilling and are somewhere around 8x to 14x the diameter of the drill bit. They have longer flutes than mechanics-length (also called maintenance-length drills) drill bits and screw machine drill bits (which are shorter than the mechanics-length drill bits). The shorter the drill bit, the stiffer it will be. The "longest" drill bits are extended-length drill bits, but I've also heard them called aviation drill bits. Of course, I'm certainly *not* a drill bit expert! ;)
It turned out well in the end. I wonder if you would get even more heat into the work with two more sides of insulating brick i.e. top and end. Efficient looking clutch.
Yes another 2 bricks, and a small brazed up frame to make a little furnace, and that would be a pretty effective small parts furnace, even with only LPG as heat source.
Yes maybe Clive. I would have preferred even heat across the whole piece rather just from one end. I need to develop the 'hearth' concept. Ideally I would get a small oven but they are silly prices, £300 to £400 typical.
Very well done, Paul. That was a lot of work. Sure, you could have bought one, but if all we did was buy things, then why do we have all these machines, right?
Well indeed Greg, and to be honest about it, as hobbyists, much of the time we are working on machines to make/repair parts for our other machines. And when we have finished those we can go back and make improvements. A sort of self sustaining hobby 😁
That was a nice save of the adapter Paul. You wonder how they got the taper so far out in the first place. I buy adapters from Cutwel in Heckmondwike when they have a sale on. Although before I bought the mill I checked on prices and 30 taper are considerably more expensive than 40 taper for some reason. Its the main reason I went for a mill with ISO40 tapers. I'm not sure of 30 taper prices when they have a sale, but I was paying less than £20 last time I got some. And those are balanced to 15,000rpm, so good for our sort of use.
I reckon the taper was incorrectly set, and only after machining, and while checking, they found it, or it missed going through a grinder to put the right taper on it, and was hardened instead, so it was left in the oops pile.
@@HaxbyShed Hi Paul, Cutwel have a bit of a sale on at the moment, 10% off with the code MTA10. Its on for tool holding, workholding and measuring equipment. Finishes at midnight 03/07/2024
Hi Paul. It’s these side projects which exercise the brain and give you the chance to learn new skills without too much monetary pain. Well done on achieving an excellent result. 👏👏👍😀
Hiya Kimber, usually I avoid colds or they get me for a couple of days max, but this one went to my chest and had me floored for about 3 weeks. Luckily I had a few older videos waiting to be edited that could fill the gap whilst I waited for my voice and energy to return. Cheers Paul
I’m kinda in a similar position. Needing to turn down a case hardened shank. I am going to try to turn it down with a CBN insert. I’m looking into the diamond tip as well as the ceramic. My machines capable, not sure if I am. Read, read and watch some RU-vid University, and read some more. I was betting on a “removable shank” but it didn’t play in my favor. So I’m left with either cutting it off and threading it/pinning it. Or turning it down to a R8 or straight shank to be used in a collet. I believe it is case hardened. So this will be fine… Probably..
CBN will work, light passes and coolant on a smaller lathe. Look at CEE and you see a 2mm cut with CBN on a shaft no problem, though admittedly the lathe used could handle a Harrison lathe in the jaw, in any orientation, no problem, and turn it to nothing.
Good work saving that adapter. You could do with a bigger tap wrench Paul, for more leverage, it's better on your hands. That clutch takes a Terry's pre unit 650 Triumph valve spring. I lost the drive while machining heavy cuts on my previous Harrison L5, the spring had collapsed. One of those fitted perfectly and worked spot on when needed, lol. Cheers Tony
Hi Paul. I wish my lathe had a nice feed clutch like that. Mine just had a shear pin. When I first got the lathe I managed to shear it several times. It's just got an M3 bolt through it now 😂. That said I've not managed to shear one in ages. This video has given me some confidence to attempt a repair on a tapping head that has a bent shaft that is far too hard to machine. I looked at it a few years ago but put it to one side because I wasn't equipped to deal with it. I think I have everything I need now, so I may well have a go soon. Thanks 👍👍
Hi Olly, you will never regret having a tapping head. When I finally finish the surface grinder wheel balancing ring you will see mine in action - 24 x 6mm tapped holes in a ring. Cheers
Hi Dave, I knew the clutch was there but had never knowingly relied on it. Now, threading is scary because there is no clutch on the lead screw. A collision could result in a lot of bent parts (though hopefully just a sheared roll pin or something - I'll have to check). Cheers
Hi, Just a few comments about the material. It is unlikely to be En24, certainly not by design. If it were a DIY project I suppose it really could be anything. En24T (aka 817M40) is a medium carbon alloy steel and usually sold in a heat treated condition - viz.the 'T' in En24T. As such it is a through-hardened material - usually used as is. A common material for steep taper tooling was En32 which is then case hardened. I bought a lot of 40/50 Int Tooling in the 70s - made by former Bristol--Erickson employees in the UK. I used to ask a lot of questions about what I was buying. The thread would not be hardened, which was important if a power drawbar was used. By copying a taper like you did, you will have avoided a common mistake. The tooling taper should be 'fast' - that is to say, by design, the male tool taper is steeper than the mating female spindle taper angle - bigger at the larger end. This is to keep the tooling location biased at the nose to prevent the tool rattling at the front. The poorly made example you have showed that clearly. Matching angles will tend to produce a tool that refuses to release cleanly. I hope this is useful.
When drilling why did you not use cutting oil? Oh! Later on I see you used coolant. Also spindle speed seems a bit too high. And why no tapping compound on the tap?
Hi Lawrence, I need to come up with a better way for reliable heat treatment. Could be a small oven, could be induction, but I'm not looking to spend much money (Yorkshireman always looking for a cheap way 😁). So, a work in progress..... Cheers
Hi Stuart, when something is not finished or just looks odd there is usually a reason. Maybe it's just a missing screw or a loose screw. You tighten it up and ... oh that's why. Hmmmmph. It's just sometimes it takes a bit of time to find the reason. Trust nothing, assume nothing ..... Cheers
Hi Carl, having the powerfeed drive clutch is a real benefit. Too easy to break them otherwise. One moments lapse of concentration and BOOM!, tears before bed time. Cheers
Likely a set of washers and a Belleville pack, stacked up so the inside of one has a drive spline, and the others have it on the outside. Pressure keeps them in contact, and a light film of oil to reduce friction when slipping.
Hi Eitri, imagine a tube with two big/thick wavy washers in it pressed together by a big spring. One washer is driven by the screw cutting gearbox and the other washer drives the power feed shaft. If the torque becomes too much then one washer just rides over the other. The wavy washers have two peaks and two troughs thus the 'ride over' is quite a smooth action (it does not chatter when it slips).
What I didn't know was how much to tighten the Belville washers (on my M300). Or indeed what the right configuration of them was. So I just did it arbitrarily and have never tested it. I'll probably try your test method and see what happens.
