T21 adjuster
The adjuster for this plane is of the well known Norris type. As with all my Norris style adjusters they have some revisions.
In these pictures you can see two small holes which are used to secure the adjuster body. One of the larger holes is for the rotating nut and the other is an extra hole to assist in work holding when machining (as in the second picture).
Work holding jig with base plates worked in different stages, and clamping screws.
As you can see here are the finished base plates. They are precisionally milled, drilled and surface ground.
A hexagon being formed on the end of the adjuster stem which will fit into the broached hexagon hole through the gun metal knob.
Completed hexagon. Doing this process on the CNC is unbelievably fast, as in the old days I used to use an indexing head and crank each cut by hand.
The adjuster stems showing the hexagon fit to the gun metal knob.
The knurling operation for the gun metal adjuster knobs. This pre-prepared bar will cut 11 knobs.
This could have been my entry for the Turner Prize but got accidentally thrown away when Claire was clearing up.
If your knurling is right your swarf will look like this.
With the knurling complete I can now cut the rings and separate the knobs in preparation for parting.
Back to the adjuster stems. Here showing the 5/16” 32 tpi ME right hand thread being cut with the Coventry die head.
As much as nobody likes a sloppy thread the nut must still spin freely as shown here.
After the larger thread is cut I then turn down the smaller portion of the spindle, turning away the unwanted threads from the previous threading operation.
This is the 7/32” 40 tpi ME left hand thread. This is the original Norris twin thread concept. The disadvantage is that the travel was a little on the fast side, but I have decided to return back to this as there are more benefits to be gained.
Adjuster components but with the stem and the gunmetal knobs to be assembled prior to taper turning.
The stem is secured easily in a collet which would not be possible after the taper has been turned.
Now with the stem secured I am able to apply some peining around the hexagon end of the stem to provide retention for the knob.
Turning the taper portion of the adjuster stem. In the past I have always avoided using a turning centre at the top end of the adjuster as shown in this picture. I have now decided that I shall turn all my adjuster stems in this way, so there will be a centre hole in all the adjuster knobs.
Going into the final stages of the adjuster assembly. The spigot on the rotating nut is swaged over a washered seating to form a retainer.
After much cleaning and fitting of the threads these adjusters are assembled for the last time. As with everything I make, all the components including the washer are made in house.
I just had to have this picture.
Seasons greetings Karl,
I simply have to know. If in the past you were able to turn the taper on the adjuster shaft without the need of a turning centre, Then why pray tell would you make the descision to use one now on all future adjusters ?
Comment by Archie — December 26, 2009 @ 9:44 pm
Hi Archie
It hurts to say that they were not perfect before and had a bit of discrepany in concentricity. Usually with most precision tooling you will see centres.
k
Comment by admin — December 27, 2009 @ 1:32 pm
Karl,
Most intresting knurl and one that defines the special attention of qualtity that is unmatched in mass production.
A straight knurl on a helical!!! as a machinist myself I’v never seen it!
Thanks, MC
Comment by John Miletta — December 27, 2009 @ 5:53 pm
Hi John
Thank you for your observations. In my earlier days a lot of people asked why my knurls were nice, clean and sharp. I have seen a few nice planes let down by the knurling so I think it is a weak point with some people. I have indexed some of my knurls i.e. small pyramids in the milling machine but the majority of people don’t notice this detail.
k
Comment by admin — December 28, 2009 @ 10:04 am
Could you please expand a bit on your reasons / the advantages for going back to a right hand and left hand type of adjuster.
Thanks
Scott
Added note: this website is a phenomenal learning experience thanks and please keep it coming
Comment by Scott MacLEOD — January 1, 2010 @ 6:27 pm
Hi Scott
The idea of having a twin thread (either two rights or a left and a right) in the first place was probably a bit of laziness – well I will own up to it. But the perfect scenario is a single thread, then the adjuster stem knob will always keep station with the back of the blade. When using the two rights then you have a differential which is great because this makes the amount of input much finer, but the disadvantage is not only does the knob not keep station with the blade but with a postive feed input the knob can crash into the blade. Another disadvantage of a differential is that it increases the amount of back lash. I hope this explains it. It is just down to personal choice.
k
Comment by admin — January 1, 2010 @ 8:37 pm
Hi Karl,
I’ve done a decent amount of machining (lathe and mill work), mostly what has been necessary for my business, toolmaker’s tools, small production runs, etc., but I’ve never gotten around to doing any knurling. What kind of tool are you using to produce your knurls as it doesn’t appear to be a standard knurl as I’ve seen? Any info would be greatly appreciated and your blog has been great.
Comment by Nick — January 20, 2010 @ 3:36 am
Hi
I would rather keep a little mystery
I started making these planes over 20 years ago and in that time there have been more and more plane makers appear from out of the woodwork, so it may be prudent not to give everything away.
k
Comment by admin — January 20, 2010 @ 9:33 am