Member postings for jacques maurel

I had seen a wonderful rainbow in Geneva, the end of the rainbow was in bank! certainly there was a pot of gold there but unfortunately I had'nt any access to the safe and haven't seen it, sorry.

Jacques

Look at my video on Youtube: **LINK**

J Maurel

I think the best way is to measure the density: weight the piece, put it in a graduated bowl half filled with water to know the volume, divide the weight by the volume, compare the result with the one for a brass sample. Brass density is lower than bronze one as brass is usually copper with about 40% zinc while bronze is copper with about 10% tin, zinc and tin having almost the same density.
J Maurel

Happy new year with milling cutters for 2015

Look at this video:http://www.youtube.com/watch?v=I57FCsvUajg

Find the density (weight devided by volume), brass has the lower density because brass contains about 30 to 40% zinc and bronze about 10% tin, zinc and tin having almost the same density.

J Maurel

You'll find a near relative of the snap tap in ME issue N°4177 (sept 2002) title: A high speed thread striking attachment. The problem is : what happens if the feeding force is more than the spring one?

J Maurel

 The problem with this tool (15° rake angle) is that it must be of the spring type for the tool not to plunge in the work as the chip is very wide for the last cuts.

J Maurel

Edited By John Stevenson on 20/10/2014 22:47:10

I've made a taper turning attachment "all contained in a tooholder"; making a morse taper with it is almost as easy as making a cylinder (very quick set up). you'll know it as soon as some magazine would want to publish it. Don't be too optimistic as I've 7 (seven!) articles waiting in ME or MEW stock since 2006 with no publication, why should I write a new one.

J Maurel

A near relative of the "Snap-tap" attachment has been descrtbed in "Model Engineer" (no photo, only sketches). Try to find in which issue!

J Maurel

New video showing the home made attachment at work : **LINK**

For cutting short threads, with no new gear, go to: **LINK**

regards.

J Maurel

For cutting short threads, with no new gear, go to: **LINK**

regards.

J Maurel

Here is a link to my website, I've gathered some informations on the attachment and there is a drawing and a photo showing a threading machine from the eighteenth century using the same principle: **LINK**

J Maurel

I've made a short video showing the attachment at work: cutting a 3/4" BSP thread (14TPI) on a metric lathe (actual lead 1.5mm).

**LINK**

J Maurel

I've made a sofware simulation using Solidworks and the kinematics application motionworks, with the example already given (20 tpi from 1mm standard lead) the error for 90 mm thread length machined is about 0.004mm, less than the lead screw tolerance!

J Maurel

Thank you to Bazyle for the links.

I'll give more informations on the snap tap attachment. in the following days. The principle of function is very simple but confusing. I've made my own attachment and discovered that there are many hidden traps in the conception. It's almost impossible for an amateur to make a copy of the genuine as no adjustement is possible. Here is a first photo:

The anwer to the 2 questions of Ady 1 is yes.

Answer to Michael Williams: the drawing 1 is just here to explain the principle.

J Maurel

The purpose of this attachment is not to correct the lead but to use the standard gear boc leads for machining any odd lead, so no change gear is needed (only the standard gear box is used).

Of course there is some geometric error as the linkage goes away, but for about 50mm long (short thread) this is negligeable (less than the lead screw error).