Member postings for Rod Renshaw

There is a theory that if you let the steel get too hot then dipping in water creates cracks in the steel? Better to let the steel cool more slowly. Work on several tools in turn letting the "resting" tools lie on a metal surface to aid cooling.

Rod

I worked at one time for the Benefits Agency and overheard one of the team leaders speaking on the telephone to a customer who was in need of a replacement cooker just before Christmas. This customer had had many grants and loans in the past and his request this time had been refused. In answer to the question "what are we going to do for Christmas dinner?" the team leader replied, in an empathetic, caring voice, "Well, you could have a nice salad." The customer was not impressed.

Rod

Thanks for the explanation of "grumpling", not come across that before. Good luck with the drill.

Grumpling?

I'm with Russell. I don't have a katana but I have often read about them and their manufacture and also watched film of japanese swords being made

.The smith forges the blade and the tang in one piece and then passes the sword blank on to the sharpener and the polisher. The sword guard and other sword furniture just slide on over the tang as part of the fitting out of the grip process, there is no more heating involved, so where is the silver solder used?

Rod

Now that's what I call animation!

I also share Phillip's awe about the skills of the component makers.

I have never seen a real-life engine rebuild go that smoothly.

Rod

Watchmakers use "rose bits" for this kind of thing, but on a much smaller scale!

Tubal Cain ( the original one) describes how to make them in his book "Simple Workshop Devices"

Rod

I am no expert on this but I think I read somewhere about gluing the boards side by side to a piece of fabric which can then be wrapped around the boiler,fabric layer inside, rather than trying to fit each board individually. Need to ensure the boards are only glued to the fabric, and not to each other! If the boards are fitted tightly together when the fabric is flat they will separate slightly when the fabric is wrapped around the boiler and should give a slightly and neatly spaced appearance.

I think one would need to make a pattern from card etc first, to mark out all the holes for the fittings, and than transfer the postion of the holes to the fabric/ wood assembly.

Rod

Edited By Rod Renshaw on 04/08/2021 19:16:31

+1 for the meaning of conflate as the combination of two concepts which can be useful or misleading, students of logic have to tread carefully to avoid falling into this trap. "

"Conflate" is also often used to indicate an intention to mislead, by making a false comparison or connection, a common politicions trick.

Rod

Nice adaptation Arthur, are you expecting a particular advantage from this combination of body and lens?

Rod

+1 for getting the right product. Some foams actually produce water as a waste product as they foam/ expand. This does not matter much in normal use as DIY filler etc, but the water will not readily evaporate from inside a tube and corrosion seems likely. Products made for insertion in car chassis voids, as suggested above seem likely to be more successful.

Rod

I use a belt sander to rough shape lathe tools of both carbon steel (not very often!) and HSS. The carbide coated paper belts cut well and last well and don't seem to load up or need as much maintenance as do grinding wheels. Though the abrasive looks very formidable I don't have to worry about bursting grinding wheels. I don't have any elaborate jigs on my belt sander so I finish tools on a conventional grinder once I have roughed out the shape. The belt sander is also very useful and quick for shaping and edge rounding of mild steel and brass parts.

Note that the diamond belt Derek has pointed to is not recommmended for HSS tools. Carbide yes, but not HSS.I understand that at high temperatures the iron content of steel will chemically react with the diamond and "eat" it away much more quickly than the normal abrasive wear.

Rod

I had noticed it and thought vaguely that the orginal poster must have started to use a naughty word and then decided to censor it to spare everyone's blushes.

Clive

Thanks for your post of 24.7.2021 at 17.10pm which describes the type of situations often faced by beginners when they attempt their first boring operation, perhaps the cylinder of a simple steam engine. Beginners tend to start wth small projects,which is fine and logical, but making small boring tools and boring with them is not always as easy as the theory suggests, as you have explained.

Rod

Andrew

I must have missed that thread.

I was told about tapered bores 40 years ago by an apparently authorititive source and believed him without thinking it through. Once you spelled it out there is clearly no reason for it to happen.

Whenever I have bored a hole and then checked it I congratulated myself on my technique!

I still think it worthwhile to try to have a stiff boring bar though as this allows a decent depth of cut and speeds up thr job, and also reduces or eliminates chatter and one gets a good/ better surface finish.

Thanks for correcting my error on the reduction in stiffness caused by length. I got my 2* 3 and my 3* 2 mixed up, for which I can only blame old age and the heat.

Rod

William

I agree with others- no table or chart.

Stiffness is important in single ended boring bars to avoid one end of the bore being bigger than the other. If I remember correctly the stiffness of a circular cantilever goes up with the 4th power of the diameter, so a small increase in the diameter increases the stiffness by a large amount. eg 8 mm is about 3.2 times as stiff as 6mm.

Increasing the effective length of a cantilever reduces it's stiffness by the power of 3 so, eg., if a bar sticks out of the holder by 50 mm it will be one nineth as stiff as if it stuck out 25mm. ( i think that's right! )

Hence the practice is to to use the biggest bar you have that will fit in the hole and cut without rubbing, with the minimum length possible projecting from the holder, and change to a bigger bar part way through the work if that is possible.

A few years ago I bought some solid carbide boring bars from China which were very cheap at the time, and which take replacable carbide tips. Solid carbide is about 4 times as stiff as steel and my boring has improved. Not sure if these are still cheaply available since the VAT changes.

If the set up is not very stiff due limited kit etc., then light cuts and spring cuts works but takes a lot longer to get a reasonable result.

We are amateurs, who cares if it takes a while!

Rod

Fantastic vice!

I wonder if they could be made today using CNC setups to keep the cost down compared to the hand fitting methods presumably needed for the original. Potentially small market though I suppose.

The Swedish firm SEVO make or made a much simpler version which seems to work reasonably well.

Rod

William

I was concerned that the grooving tool might only be intended for shallow grooves and lack side clearance, and so be part of the problem. If it works use it.

Howard has covered all the other issues so your set up should now work ok.

Let us know how you get.

Rod

William

Your new set up looks much more promising. But as has been said the grinding does not look good. I wonder if you need a finer grit wheel.

Arc do "Parting tool blocks" for holding blades which might suit if the dimensions are okay.

Also, your original set up with a square section tool can work okay if you get a proper HSS parting tool
(ie a parting tool shape ground on the end of a piece of square section HSS, all the ME suppliers do these) rather than the grooving tool you were using. All provided you pack it up (down?) to centre height and near horizontal. Blades are more versatile but if you only need to part off smallish stuff the square HSS parting tool works okay and might be easier to fit to your holder.

Boats are not popular, as has been said, but the one you have is more rigid than the original diecast myford offering. I think the newer ones are hardened steel so may not be easy to drill for dowels. Parting tools, once set, are often left alone for extended periods so it may be okay to just adjust the tool, packing and boat, then clamp up tight, and not fix the boat at all. You may have to experiment with these things.

Good luck!

Rod

Richard

Well done you!

Your situation was very much not your fault but your experience may act as a reminder to the rest of us about how important it is to keep the internal threads of chucks and similar fittings really clean.

Rod