Member postings for Roderick Jenkins

I needed to cut a thread on the end of an ER11 parallel shank collet holder when using it as a spindle in my home made tool post miller. This was too hard to thread with carbide inserts so I warmed up the non-collet end with a torch until it was somewhat hotter than blue but not glowing red and let it cool. Cutting the thread was fine after this treatment. I did wrap some wet rag around the shank to try and stop too much heat getting to the collet end.

HTH,

Rod

Hi Bruce.

I've been logging all my mistakes and cock-ups over on ModelEngineMaker under the Tangler pseudonym.

Cheers,

Rod

This is Len Mason's take on a small parting and grooving tool in "Using The Small Lathe":

I've just used mine to cut grooves for 3mm E clips

You do need to make sure that the hacksaw blades are solid HSS not Flex Bi-metal.

Rod

I've been getting on with my Farm Boy. These are some of the governor bits:

Rod

Very nicely finished. Mine aren't nearly as nice.

Rod

My stupid machine won't play with the computers any more. I HATE RS232

Rod

Actually, I've given up using a pressure washer on the patio. I find "Patio Magic" more effective, longer lasting and much easier. I had to go and find the Karcher in the loft.

Rod

Yup. That's what happens on the beach round here.

At £4.75 for a large bag of sand ( c 25kg) the loss is not great. I used about a kilo to do the con rod and my steel fabrication.

Rod

This is a messy method. The con rod was held down on the patio with a welly clad foot for blasting and there is wet sand everywhere but the garden can cope with that. As for the texture, I can just feel that the surface is not silky smooth but is more uniform than the machining marks left from the milling.

I've been doing some really crap welding with a basic Parkside buzz box that I was given (I will not show this, it is too embarrassing ). The blaster made a decent job of cleaning off the fuming and much of the discoloration, thereby emphasising all the slag inclusions. I guess one could try a different medium but I'm not really up for spreading £50 of wet garnets over the garden.

I have no other requirement for a noisy compressor so this system will do for me.

Cheers,

Rod

I like the effect that sandblasting gives to the finish of aluminium engine bodies and components so I thought I would have a go with one of the £12 accessories available for my Karcher pressure washer. These are the results using kiln dried sand from Wickes

2 similar components (both failures for various reasons). I've shown 2 different lighting conditions which I hope capture the effect. I was rather pleased with the result for very little outlay.

Rod

Edited By Roderick Jenkins on 04/09/2019 23:28:47

Have another look at ARC, I've just had a notification that they've slashed the price of some of their 4Jaw SC chucks - almost in half

Rod

Worth bearing in mind that tethered hydroplanes were popular at the time - definitely not models. ET Westbury was at the forefront of designing engines for power.

Rod

We really enjoyed the Kauri museum. There is quite a bit of engineering interest

Rod

Hi Martin,

'Twas us. You must have had a very hot and tiring week at the show.

There was a magnificent array of stationary engines being exhibited - all chugging away so thanks to you and all the other exhibitors. It was really nice having a chat with you.

Cheers,

Rod (and Sally)

As Andrew says. I've been using my 3 jaw like that for the last 30 years.

Rod

Chris,

Your question is a little too complex for a simple answer because once a tool has been quenched to give its ultimate hardness it is usually tempered to give a compromise between hardness and toughness (resistance to fracture) suitable for the job in hand.

If you are interested in this subject then I strongly recommend Tubal Cain's "Hardening, Tempering and Heat Treatment", No.1 in the Workshop Practice series.

Just as a taster, TC quotes the "as quenched" hardness of silver steel at c.67 Rockwell C and High Speed steel as 65 HRc. Both are pretty brittle in this state. If you really get in to it then you can make Dave Lammas' Hardness tester, castings available from Blackgates!

HTH,

Rod

Right, now about these Velocette gears...

A couple of points if I may:

I think the Sherline lathe headstock is the same as on my Sherline /Denford mill and this will take a full No.1 Morse taper. If using the full length 1MT then you will need a smaller diameter drawbar. Mine is 1/4" and holds an ER11 1MT collet chuck nice and firmly. The drawbar need only be a length of studding with a nut.

My experience of blank end arbors is that they are harder than mild steel but not excessively so. I do not think the shank will be any different from the head and they are sold so that you can modify them to your own requirements.

Hope this helps,

Rod

Graham,

That's a good looking gear and, frankly, I wonder if for a gear with that many teeth and such a shallow angle one would really be able to tell the difference between one that has been cut straight across at an angle and one that has been cut in the correct helical fashion.

Rod