Member postings for Ajohnw

The best thing to do with a really stuck Phillips is to to get hold of some JIS screwdrivers that are really made of tool steel. Anyone who uses mine on wood screw knows that I might chop their hands off. Good ones are hard to find.

John

-

The Pultra is up to £225 and still not hit reserve.

Main reason for posting is this

**LINK**

If that is still in good order the mind boggles. If the history is correct it might just be.

John

-

Nice work Rod. I have to do the same sort of thing for my Pultra. I could adapt a 10mm collet to hold a chuck but that increases the overhang. The Pultra 3 jaw doesn't have any leverage additions at all, just uses finger friction on the rims of the chuck. Rather than use the keyed type I feel I would just make some longer levers.

I wonder if the chuck has a hardened scroll plate and heat treated jaws? One of the problems with the larger chucks in the past has been a soft scroll plate that can strip easily. Some of the cheaper quality chucks get round this by making the parts in a sort of chunky fashion and still heat treating them.

ARC/Ketan might like to note that for some reason 80mm versions of these chucks are hard to find as are light weight 4 jaw independents of this size. The Peatol one is a solid block of metal. 50mm 3 jaws are all over the place but I feel they are too small even for a Pultra.

John

-

Have you ever owned a set of whit spanners?

And Tim hex heads and the likes have nothing what so ever to do with the type of standards I mentioned - only the tolerance on them.

John

-

Must be freudian slip to show what I really think about all of them.

John

-

Thanks Andrew as I have wondered about this.

I still suspect standards have something to do with it. They are generally established in conjunction with the people who manufacture who will look at it from an ease of production point of view so once established no one tries to do any better.

There are some excellent examples about. Nuts and bolts. GKN used to churn out fantastic numbers at very low cost that had a much better fit than they do these days, I have bought precision bolts for clamping things and I would say that these do tend to be close to the rights size and cost a lot more. Another example is the occasional ebayer that comes across some cut thread screws and nuts. The fit is generally excellent, just short of interference. A weirder one that I came across due to work is HGV brakes. Once up on a time people sat down and said ok lets make this truck stop - now they want to meet a standard. In both cases due to checks they wouldn't be "bad" anyway. That sort of sums it up. Some trucks used to stop quicker than others now they are all likely to be much the same. Sometimes standards are good sometimes i feel they are a bit questionable and the limits have been set wider than they need to be. One thing I gather from your post and measuring them is that ISO 2 results in pretty narrow range of measured sizes. I'd guess nuts and bolts are just the same but I just use them.

At least at home we don't have to use traceable items otherwise we would have to buy taps stamped with a tolerance and even checked to it. Yet - maybe the boiler people .................?

John

-

Edited By John W1 on 12/08/2015 13:35:57

The trouble with an exact phillips head and driver is that they are designed to cam out to make mass production work easier. The Japanese modified the bits and called it JIS. The main change was to the cam out so they are not so inclined to slip. They also must have had better control of the torque settings on the power screw drivers they use for this sort of thing.

For wood screws it probably pays to stick to poxi and be sure to use a poxi drive bit or screw driver with it. The heads of the screws should be marked differently. Think that is on the wiki. There also seems to be some screws about that don't fit into either category.

John

-

Edited By John W1 on 12/08/2015 13:07:18

In terms of hss tool angles this might help. A tool that will work well on any material. All of the angles are more or less the same except that there is little back rake. There is no point in being precise. It's the easiest tool to grind - bar turning and is often ground with less rake than this one.

It's on a 3/8" toolbit. Reflections and bits make it look a little odd in places. It's sharp and straight sided. The rad is straight as well and has been stoned on. All of the surfaces around the cutting edge have been polished with a stone. The finish of the tool is important as it will be transferred to the work and in the case of aluminium poor finish will generate more friction melting it and causing it to stick to the tool unless the cutting speed is bought well down. I periodically run the stone around the tool while it's in the lathe to keep it sharp. Some turners always do this before taking the final cut.

It would take a huge post to go through everything so just the basics. Actually I don't think that is possible anyway. A better idea is to grasp the principles and try various things out

Rads on tools distort the material more than a straight edge as it's being cut so for normal turning small is best. It just needs to be large compared with the feed. This may not be the case with extremely large rads and rather shallow depths of cut. It can be interesting to try this by turning using a parting off tool at a modest angle to the work angled in the direction of the cut. A lot depends on how tight the machine generally is.

The top and side rake form a wedge. The top rake will tend to pull the tool into the work. The side rake resists this tendency. On materials such as aluminium it's possible to increase these angles a lot and balance them so that very little effort is needed to take much larger cuts than a machine can normally take. The best balance is when the side rake has reached a point where the tool almost self feeds. Top rake to experience this is of the order of 30 degrees. Side - gradually increase it until this happens.

The catch with trying to do this on all materials is that having lots of side clearance weakens the cutting edge and on brass for instance the same tool might even self feed. On cast iron it might even chip and will wear more rapidly due to the very acute angle at the cutting edge. For various reasons including heating in use harder materials need reduced wedge angles and rakes. Just to complicate things more acute angles cut more easily which can reduce tearing. Slow speeds can help with that problem as well at times and get rid of boring bar chatter.

Back rake simply helps guide the swarf away from the work.

Front clearance is needed to prevent rubbing. If the tool happens to be above centre for some reason more is needed especially on small diameter work. This is why tools should generally be set a touch below centre - the centre height of the work may vary along the bed. The tail stock might be a touch low etc. Boring is the other way round plus the bars will bend a touch.

The other factor is heating effects. People might not think that their tools don't get hot but the problem is right at the tip of the cutting edge not the whole tool. If sharpened correctly they will cut paper. They have a very fine edge. Heat conduction rates from the edge drops off as the wedge gets sharper. It's even possible to weaken HSS when the tool is being ground. Any sign of tempering colours appearing is bad news.There are different grades of HSS. M42 for instance is reckoned to have better red heat strength than others. It's very easy to wreck some grades this way. Less so as the cobalt content goes up. 5% cobalt / HSSE is often used for any sort of metal cutting tool for this reason - to help maintain the cutting edge not the whole tool.

Tool bits needn't be large. During training I mostly used 5/16 HSS on machines that were easily capable of removing 1/2in of 4 to 5in dia mild steel along with a very heavy feed. A 3/4" or bigger super weld tool would be used for that sort of thing. In the normal range up to a 0.150" cut or so 5/16 bit were fine except for one aspect. The holders applied something like 15 degrees of back rake - grinding that on the tool would weaken it and also make grinding them more difficult. Generally when steel is provided for some job 0.150" cuts aren't needed. On a large machine to get the best out of them this is the sort of amount of excess material that is needed. A large machine in very good condition may need a cut of at least 0.040" in order to take all of the play out of it so that a consistent finish can be obtained. Materials don't have consistent hardness. Some machines would need more than that. The general idea is to use similar sized cuts to clean up and finally size a part. Some of those cuts would be used to determine exactly how much material is actually removed and the cuts adjusted accordingly. I once bought a sort of slightly larger super adept, similar thing but a smaller than a zyto. The cut need on that to get a decent finish was around 0.050", 0.1" off the diameter. It had a 1/2hp motor. That was in mild steel. It might be more or less on brass or aluminium etc. The machine went in the bin, crap head stock bearings and no way to fix them.

John

-

I didn't get the exact name of the chuck correct should be Rohm but a few people have mentioned slipping, larger drills and drill position so I tried it on mine which is a Porta Validus and found the same thing. The Validus supposed to be self tightening. It is obtained by there being some back and forth play in the chucks outer body. Hand tightening force the outer body forwards. Pushing the drill home rests it on a part that doesn't move at all. Rather odd that it increase the grip because on the face it the self tightening can't do anything at all. One thing for sure though when I do that it doesn't slip. I only have problems anyway if taking a lot out with blacksmith drills on harder materials.

The whole idea of these self tightening chucks is that the grip tighter as the whole body of the chuck and the drill is pressed back. If it can't be then it can't self tighten which is a bit of an incorrect description anyway - they tighten more under pressure.

Perhaps another answer to slipping to only leave a few thou gap between the end of the drill and the part that doesn't move to maximise the contact length and reduce the chances of the jaws bell mouthing which they will if there isn't sufficient drill in them.

John

-

More recent electric drills seem to have some sort of automatic spindle lock so there is plenty of chuck to grip.

The keyless chucks on lathes often grip larger drills better if the drill is pushed right back in as far as it can go even on the Rhone ones.

I still use a plug in Elu, 3/8in at times but fitted with a 1/2in Jacobs all steel chuck with 2 rings. It grips well and the rear ring is wider than some. Your best bet might be to go back to not remembering where you put the chuck key.

John

-

I suspect it's not all that uncommon for that sort of dealer to finish up with item no longer available. My latest pillar drill came like that. I asked if I could come and look - I did and they cancelled the listing and sold it to me saving us both some money. That one was buy it now too - they told me not to worry about that - it would be available when I got there.

John

-

I suspect the most valuable parts are the lovely wooden handles on the gravers providing there is no wood worm. I did ask what the reserve was to enable me to judge it's value - no reply and in any case as some of it is probably unrecoverable well past it already.

John

-

I feel this one should be added to this thread - It even has a reserve and bids

**LINK**

Might be classed a Super Dupa Adept project for extremists with a tendency for self harm.

Replace the broken bit with brass ????????

I suppose I could be tempted by the shear challenge but.....................

John

-

I suspect people are forgetting that lathes face concave by design so there is always a degree of rubbing. It should be a truly tiny amount concave but I have no idea how good some lathes are in this respect.

One of the advantages of the disposable tip blades is that the holder is thinner than the tip and the tip can be correctly shaped. To obtain a suitable holder I bought one complete with blade from RDG. The tip is tapered front to back and down the sides. I do expect to have to buy and industrial blade as the width of the RDG one seems to be uncommonly thin. The blades are 1in deep but the tip fits lower down and the holder has the same profile as the Myford QCTP's. The extra depth is available because the blade overhangs the end of the compound slide, actually by not much more than an ordinary parting off tool does. I did wonder about making one for a QCTP but lacking a universal mill for horizontal work that would be a pain. It would be a lot easier to make one to fit an ordinary n way tool post.

John

-

Might be good way of getting them to the size they should be Neil with a suitable jig.

Size wise those Arc taps don't seem to be any better or worse than others. I'd guess more could be paid for them elsewhere.

I bought most sizes just in case I need to tap stainless again. If I needed to do that often I would be looking for HSSE/5% cobalt or even M42. One size was out of stock and I sort of requested they sent me them FOC for postage at least when they are back in stock - Fat chance.

John

-

Headstock bearings may be your other problem. High precision will cost rather a lot but you may find that they are a standard size and while standard bearings wont be so "good" they are likely to be better than scored and worn high precision ones. Depending on the arrangement this area may be why some of the gears haven't faired too well. The shells wear oval over time.

The bearings on some lathes are adjustable - I understand they aren't on Chipmasters pass on this one. If you do change them it will probably pay to find some one with a bearing heater and a press especially the press. That's why I need to visit some recon people. Getting the spindle out removes the rear one but I would probably damage the spindle if I tried to get the front one off. Getting the shells out is usually easy but it's best to have some preturned discs available to press them back in with a hefty length of all thread and some arrangement to make sure that the all thread is pretty precisely axial. Then ensure they are seated properly. The method of preloading bearings varies - I use heat. I expect to be able to feel some heat inside the spindle adjacent to the rear bearing after the lathe has been running for say 1/2 hr.

John

-

Cost of HSS taps vary very widely. They come in 2 style, ground thread and cut thread. There are also variations in the grade of HSS used. They needn't be expensive, these for instance which in real terms are ok

**LINK**

In terms of ground and cut thread one thing I have noticed is that taps these days tend to measure slightly over size. I'd guess this is some sort of standard where as some time ago taps tended to measure exactly on size. Same sort of idea as a reamer - the size they produce is very slightly greater than their diameter.

Dies come with the same variation except at very small sizes I doubt if ground thread can be found. BA for instance are usually all cut thread. The other difference is button and split dies. Personally I will only buy split as they can be adjusted a little if the usual die stocks are modified.

The problem with carbon steel taps and dies is that often especially in sets they aren't made very well. In the past there have been high quality ones available. There probably still are from true industrial suppliers but they will probably cost more than cheap HSS.

Well made carbon steel taps and dies are fine on most materials but can be a problem on materials like stainless steel. The other aspect is how often they are used as they will wear out more quickly than HSS. The harder the material the faster they will wear out.

I recently bought a cheap used set of M8x1.25mm left hand thread taps and a die in carbon steel. Made by these people

**LINK**

The fact that they are carbon steel doesn't bother me as they wont be used very often. They are dead sharp and accurately sized by modern standards at 8.05mm dia. For odd jobs I would still buy carbon steel if the price is right and the quality adequate. Breakages of both types really depends on how they are hardened. The usual reason for breakages in very small sizes is twisted holes down to poorly sharpened drills / drilling machine spindle not being square to the work / the tap being put in at the wrong angle and aspects like that.

Cheap carbon steel full sets ? I needed to cut a few UNF sizes some time ago and thought why not so bought a set. The holders were pretty useless and worse still the dies especially wouldn't really cut. The taps could with a lot of force. I didn't go for the cheapest of the cheapest either. These days I would just buy the ones I needed rather than doing the same thing again. Although I work in imperial the majority of my taps and dies are metric. If I was following some design that wanted say 1/4in BSF I would simply replace it with M6 if I needed to. BA can be replaced easily. I also have most of the usual sizes of ME especially in 40TPI. ME is unique and can't really easily be replaced with standard metric taps and dies.

Thought I had better add why the set was so bad. I suspect that they had never been near a grinder even for final sharpening along the flutes. Something to watch out for when buying.

John

-

Edited By John W1 on 11/08/2015 10:35:25

I've been looking at D1 3 Boxford spindle fittings recently. From this it seems there is some standard relating to the taper in the spindle so that a bush can be fitted to take a standard morse fitting. It could be that D1 D2 etc all have their own standard sized bushes. Boxfords spindles for instance take a No 4 1/2 ASABS.10 that has a 3 morse socket in it.

John

-

I wonder if these are cast parts? Mainly because of comments I have seen in older sources - "good quality milled brass" which I assume means entirely made of the usual brass bars from a reliable source.

I've gained the impression that when brass is cast for serious purposes it needs to be closely controlled.

John

-

0.030 is common round here with all of the ones I am aware of. My father had machines reconditioned regularly. His solution was to tell them to stand the bed upside down on parallels aligned with the feet and take their 0.030 off the feet. The aim being to remove any errors in the slideway grinders bed. He followed that with the comment that he would mic up the bed and if they took more than X off he wouldn't pay them. He took a very dim view of taking 0..030 off and packing up the saddle. It's pretty common. My last place of employment bought a recon'd chipmaster - new bearings, bed regrind and the saddle packed up in this case with metal strips. I recently saw mention of the use of plastics but this might be to get smoother movement. The saddle and cross slide etc will have been reground as well. Some machines carry the saddle on a sub table to ensure it is an exact fit on the bed.

Actually I will be visiting a recon place shortly and will ask about thou level regrinds. They charge around £40 an hour which isn't too bad for small jobs. I'm assuming this is a flat rate. Could be time on grinders also has to account for the cost of the machine.

John

-

Edited By John W1 on 10/08/2015 17:37:51