Member postings for pgk pgk

All but 2 of my rads have typical square head bleed cocks.. those two I finally got to exmainign with a magnifying glass (old age is no fun) and the blessed things are male hexes.. 3/16 socket too small and 7/32th too big. 5mm too small and 5.5mm too big and I'm out of owned options.

Anyone guess what they really are? 5.2mm or 13/64? Why in the name of the almighty would you choose a wicked size like that????

I made mine out f silver steel and never got around to hardening them..but then i've only used the knurling tool once in the 4 mths since i made it..so wear isn't likely to be an issue..

You can cheat with screw cutting on the lathe ..in the sense of cutting a partial thread then running a die down to clean up and complete it to depth - the lazy way to avoid calculation and thread wires. saves a lot of die effort on a long thread.

I'd be suprised to find a mill there - unless milling grain (or stray ramblers). There was enough hazard getting that pic..doing any digging would mean demolition first.

Access to the building is via a right of access across my property, then a gully stream ford, across someone else's field and then into it's 2 acre plot. It's in a frost pocket with no mains services and it's name translates as 'the pauper's house'. I only bought it just in case someone wanted to develop it (rumour of a shooting lodge). It was cheap.

Is it possible to just shorten the MT3 taper and then fit a homemade conversion into the end to regain the correct length. I'm assuming that there will be enough grip left in the remaining taper and the conversion extension is made smaller od than the existing taper so no need for clever matching up.

It's possible... this is the inside of the kitchen (with some of the bedroom and roof)

I spotted this lump in a derelict cottage I own. Recovery would be hazardous. Anyone know about it?

As far as this relative begginer understands the ideal cutting rpm for 1.2in mild steel is around 350RPM .. so running HSS at 2000 or 2500 suggest to me that your burnishing rather than cutting.

Also as far as I understand the finish will depend on the grade of steel..leaded giving a better result and the radius of the tip of your HSS tool as well as depth of cut and feed rate. It;s also going to depend on the rigidity of the lathe.. to have the option of 2500rpm - what lathe? My crusader only goes to 1800+ rpm and I've noticed that on some gash mild steel I get a better finish with a heavier cut on a wide radius HSS tool than i do with a finer cut tool...but that may also be due to a better stoned finish on the larger radius tool. For practical reasons using an indexable tool I can polish it nicely on the lathe with some scotchbright rather than keeping on fiddling.; the depth of cut and speed of cut making up the time.

I take your point. Perhaps the use of a drill chuck will aso introduce more potetial slop to he start of that pilot compared to a collet - the chuck body itself having some inherent 'slop' and being further from the quil than an ER32 collet (in my case) would be... the greater rigidity of the system the better the hole start..

I bought my boring bar here **LINK**

But only because I wanted to play/try some indexable tooling and was unsure about the mounting angles and suitable inserts. The hole was a through hole 90mm deep 29mm wide in aluminium (and a couple of cast iron bushings to fit with a 24mm bore)

I'm still a beginner too (bigger lathe) and the amount of holes Ilve bored is still on a one hand count. Even with spring passes I found that my 16mm boring bar still flexed enough to make a tiny difference on a 90mm bore.. which didn't matter that time but I promised myself that now I own one commercial indexable bar I'll have a go at making a larger diameter one myself for next time using the reference angles for the insert from the first. Mine is OK from an 18mm hole but the 29mm I finished with would likely have been better swapping to say a 25mm bar at the end. Of course that will mean making a holder to take it too...

..or a short then long series centre cutting endmill for the pilot...?

...vacuum pipes in shops...shows our age.. as well as those wire pull thingies in drapers from counter to till.

Apparently there was a London to Croydon vacuum railway run by pumping station. The seals on to top the tube slit reportedly being tallow lubed leather. Every morning when the pumping station started up it rained rats over south Croydon...

To continue the discussion.

It wasn't center popped...just straight in with a cenre drill by DRO then the different drill sizes to their jobbing lengths - the 4.5mm split point only goes about 1/3 the depth. the 6mm further..But yes it was pecked to clear swarf as were the follow on drills. The final 7mm split point cobalt was a new drill and went through the pilot holes and the remaining stock like butter - I did clear swarf as it went but it would have happily chomped straight through.

Chester superlux mill bought earlier his year...not the best mill in the world I'm sure..give it a hard time and there's nasty rumbles from the head bearings and vibrations. The head moves on these rather than the knee/table.

I'd squared the stock myself after freshly tramming the mill..and tramming the vice both for travel and checking for 'perpendicularity' to the head. Quill extension was just that needed to bore the depth. As for how square the stock was.. well the end in the mill measured with a mike exactly the same across both left and right of the stock and the edge was checked with a machinists square as square in the vice ...but all those methods will have limitations.. and front to back there isn't a reference on the mill vice apart from trusting the fixed jaw. A square on the corners has limitations too.

Perhaps it's expecting too much of a drill bit in an average chuck to drill perfectly vertical over that distance anyway since it works out as 0.36 degs deflection and in reality i doubt I had the combination of all factors better than that.

So it has to be a case of finding methds to drill to make up for the inaccuracies of the operator..and drilling from both ends and using collets to hold the drill bits might be a way forward.

I had need to drill through 80mm hot rolled that had been squared (as in no mill scale). I finished late last night and haven't doube-checked but I think it came out 0.5mm off center exit compared to start.

Now that doesn't matter on this applcation but I was curious as to how one might improve on that. This hole was located by DRO then a fine centre drill and cobalt split points full depth of their jobber lengths 4.5mm, 6.&. 7mm.

the mill had been retrammed shortly before to less than 0.01mm over a 220mm span and i was using a moderate priced drill chuck in the mill.

Would it have been better to bore from each end? Would it have been better to make the pilot hole with a fine endmill? Would it have been better to use collets instead of a drill chuck - or all of the above?

I just cut the male dovetails on my current project - bit the bullet and went full depth (7mm) at a slow 170rpm for my 25mm cutter with a handheld airblast. Feed rate was held very slow - just below the point of rumble and I was turning my handle to a slow count of 20 per rev. If I had to guess that's probably no more than a few mm per min and every time the compressor started up I started too. But it went through with a very neat cut, hardly touched the sides on a spring pass and the cutter was cool at the end of the first pass. I'm happy to have learned something.

Can i ask some more questions re dovetails, please?

One of my first projects when i kitted out was to make a few extra QCT-holders. The female dovetail is quite wide on those so after milling the relief slot i fed in to each side seperately and had issues...

If I fed in too far then lots of vibes and chatter and at the end of each pass unless very careful it would tear out and bounce. I finally succeded i making them all by the tedious process of multiple fine passes. The other problem was the tendency for the cutter to try and pull the machine down or pull the cutter out of the er32 collet and I suspect flex in the cutter causing the leading edge to snag at the bottom despite being a tad above the base of the relief slot.

It may well be that i was trying to feed too fast? It was a 25mm dovetail HSS 60deg cutter - not a cheap one - with lots of coolant hand misted during the cut.

Current project needs dovetails again.. shallower at least - at 7mm deep and therefore 4.05mm undercut. If I understand correctly you'ld feed full width leaving a finishing pass? What sort of speeds and feeds (feed will be manual as will coolant and air blasts)? Chester lux mill. Piece of hot-rolled.

Any benefits in indexable cutters here?

Edited By pgk pgk on 27/08/2015 10:31:50

Local scrappy scored some useful parts for me including some round bar lengths of steel with just a dusting of rust approx inch diameter and 4 foot long. This was from a rubbish clearance from a deceased hobbyist.

Some of the bars have off-white painted ends, some a dull mid green and one the same green wth a black '1' in the middle.

I realise colour codes can be personal amongst stockist but just on the off-chance it rings a bell....?

(The haul also included 2 different v blocks a pair of v blcks with clamps. 2 different size bullfinch burners an engineers clamp and a 'eclipse' holder with assorted blades which include hand slittign saws and files and knives.. about the size of a thin stanley knife in it's original cardboard box. £20 the lot seemed a bargain)

Back when I was into archery I owned a simple arrow straightner. The principle may well apply here:

A base rail with two pairs of bearings that could be slid along, A central column holding a DTI and a central squeezable clamp to apply pressure. Rotate the arrow (wire) to find the high spot, adjust the bearing spacing for gentle or more narrow degree of bending .. squeeze the hand clamp by judgement - rotate wire to assess result and repeat until the arrow length was true. We'd expect to straighten a 2213 (220thou od by 13thou wall thickness) arrow to a half thou along it's length with practice. Too heavy handed and you risked denting them.