Member postings for Johan van Zanten

Hi Jason,

Thanks for the link. I found some nice photos of the Allman engine.

Best regards, Johan.

Job done !

Thanks both of you.

Best regards, Johan.

How do I edit my member profile / More about me?

Hi Steve,

I have no special knolidge about the Vega but I am afraid the carbs getting too hot, causing vapour lock. You have to use an insulating sleve between the head and the carb. This is the usual practize on model aircraft engines.

Best regards, Johan.

Hi Nick,

Single phase motors make a humming noise, wich is different from bearing noise. This is caused by the way they work and is called cogging noise. That's why manufacturers like Brooks mount their motors in silent rubbers. Two phase motors ( with a running capacitor ) behave a little better at this point. 3 phase motors are quiet. But all motors can have bad bearings wich makes a rumbling sound.

Best regards, Johan.

Some generatorsets made in the Netherlands.

Hi Piero, I made one myself. Can be very small and works great. See. http://madmodder.net/index.php?topic=3776.0. Best regards, Johan.

Hi Kevin, Some years ago I made one in scale 1:10. See my album. http://www.model-engineer.co.uk/albums/member_album.asp?a=6778 Regards, Johan.

Hi John, Good tip! I'll try next time.

Hi Martin,

When you tumble brass parts with stainless steel medium (as on the picture) you get a grey haze on the surface of your workpiece caused by the rubbing of the s.s. When you use commercial available hard steel needles or satellite’s there is no noticeable discolouration. When you tumble steel parts with brass medium the steel workpieces comes out light yellow. Ceramic medium causes no discolouration but due the dimensions of the stones it is difficult to reach the corners of your workpiece. I hope this answers your question.

Best regards, Johan.

Hi all,

I follow the tumbler discussion on this forum for some time but I think it is not that easy to get good results. I made my tumbler 20 years ago and use it very frequent with good results. The driving unit is a geared fractional horsepower motor with a speed of about 100 rpm.

My drums are made from sewage tubes with a diameter of 120 mm, carefully covered with rubber sheet.

They are half way filled with medium made from offcuts stainless steel . The sharp edges are essential to reach the corners of the workpiece. I use one spoon of siliciumcarbide grit as abrasive.

To lubricate the process I use a cup of water with a spoon of washing soda. The tumbling time varies depending on the workpiece between 12 and 20 hours. For a brass or bronze workpieces I use brass medium. Tumbling is ideal for (silver)soldered workpieces. The parts of my latest engine are tumbled for 15 hours direct from the mill. I am looking for a reasonable priced bowl for a vibratory tumbler. This shortens the operation time.

As you see there are happy tumblers in the model engineering world.

Best regards,

Johan.

Hi Martin,

I use houshold soda. One spoon per liter. Cleans great,No foam at all.

Best regards, Johan.

Hi Maurice, I se nobody answers your question. I never build the Centaur engine but lost of other designs. I think 300 to 600 grams is more than enough. Don't use needless strong springs to prevent exessive wear on the cams. Succes with your engine. Regards, Johan.

Hi Rik, I think John is right. By connecting both scales to your mill you create a ground loop via the cables and the readout unit. This makes the readout sensitieve for spikes generated by the motor driver unit. Electrical insulating one or both scales from the mill meigt help solving the problem. You can easily try it by using some electrical tape. Regards, Johan.

What about this?

I used a timing belt from my car inside out for years. Works fine!

Hi Andrew, Go to www.emco.or.at Click machinen, Emco, service anleitung, Fraisemachinen, Emco fb2 and you find a free download of the user maual and the service manual in the German language.

Regards, Johan.

Hi Ian and John,

Do you mean the radiometer from Crookes?

**LINK**

Regards, Johan.

Hi Dave,

I am not a steam specialist but have made many piston rings for IC engines. I Always use the Trimble formula. The thicknes of the ring should be between .040 and .045 of the bore diameter. For a bore of 38 mm the ring should be 1.67 mm thick. This is rather critical! To thin and there is not enough wall pressure, to thick and you have to much installation stress (broken ring). The gap should be .15 times the bore, that is about 5.3 mm in your case. The hight of the ring is not inportant. I should go for 1.5 a 2 times the thickness. in your case `2.5 a 3.5 mm. for a steam cylinder. I Always use continous cast iron bar.

I wish you succes with the make of new pistons and rings.

Kind regards, Johan.

As I read your mail I suppose the nuts are not the problem but the leadscrews. They wear on the most used position and create backlash. When you try to correct this the nut jams on the less used position creating more wear on the nuts. You can only correct the wear on the nuts ( at the less used position ) and NOT the wear on the leadscrew. Replacing the nuts only is of no use. To cure the problem you have to replace the leadscrew too.

Kind regards,

Johan.

Edited By Johan van Zanten on 01/06/2013 19:17:10