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By gasman
#962179
I might get shouted at by the traditionalists but as I said at the start I am using this to learn about metalworking and this step can always be done again.... so yesterday I did the cap iron screw - well almost finished anyway
I had bought some 8 or 12 inch lengths of brass rod - 1", 3/4", 1/2" and 7/16" from an eBay source and I was going to use a length of the 1" rod to turn down to get the level cap screw. However when they arrived I thought why not make it in 2 parts.
So I started by taking the 7/16" rod and using my new acme 7/16-10 die to thread it. The really irritating thing is I cannot find the photos on my phone of quite a lot of this so I have retaken some but some crucial steps are missing - very sorry no idea how that happened.
Anyway I needed 2 goes at using the die to cut the thread because the first time the thread was not square, but by tapering the rod slightly first on the lathe it was much easier and it cut so easily with cutting fluid.
When that was done I cut the 50mm of threaded rod off with a hacksaw, mounted that piece in the lathe and turned the end half inch or so down to 8mm diameter so all traces of the thread were gone from that bit.
Then I mounted the 1" rod in the vice and cut about 20 mm off the end
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. I mounted that small piece in the lathe and turned the end flat - then drilled a 6.5mm hole in the end to 10mm depth and used a 5/16"-26 tap to tap it. I had recently bought from eBay a huge pile of taps dies and reamers so I have lots of sizes to choose from
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I then found a 5/16"-26 die and threaded the 8mm diameter unthreaded part of my short length of acme-threaded 7/16" brass rod... and then screwed them together.
When this was then mounted in the lathe I turned it all square - and I figured that in the process this would tighten up the union between the 2 pieces due to friction. I thought it was worth a trial and it looks to be working so far as it is very solid
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I still want to shape the end of the lever cap screw better, plus it needs knurling obviously - but at the end of yesterday it looked like this and I was reasonably happy as I had learnt quite a bit about tapping, dies, brass etc etc. I have plenty of brass rod left...
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Cheers Mark
By gasman
#962582
Mmmmm... no one has commented which leads me to think I have committed some cardinal sin in using 2 bits of brass to mke the lever cap screw. Oh well!
I turned my attention to finishing said screw.
First to knurl the knob. New skill to acquire as well. I looked at a couple of youtube videos and it all seemed straightforward - however don't think it has come out very well...
I mounted the knurling tool in the lathe and the lever cap screw in the chuck
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I turned the lathe on at its slowest speed, manoeuvred the knurling tool till it was either side of the screw and tightened it slowly until it was engaging. Then kept on and tightened gradually...
It all seemed to be going smoothly but the final result was a little disappointing in terms of how precisely defined the knurling was. Anyone any ideas what I did wrong or how to improve?
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Next stage was to shape the end - so I ground a curve on one of my lathe tools
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Then, slowly and steadily cut a shallow curved groove in the top of the screw and then polished it out
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I think I need to take the edges off the top and bottom of the knob?
Thanks for looking
Mark
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By Jamesc
#962596
Hi Mark

It's looking good. With regards the cardinal sin, certainly not in my book. It may work loose over time in which case an application of Locktite should sort it out.

Keep the posts comming, I am very interested in how it turns out

James
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By Pete Maddex
#962600
Jimi said you needed to get the diameter right so the knurls would line up after one revolution to produce a good knurl.

I like Karl Holtey ridged knobs (the knobs he makes, stop sniggering at the back) I think they look nice, have a look here http://www.holteyplanes.com/blog/page/2/

Pete
By gasman
#962623
Thanks James and Pete - I have read a lot of Jimi's posts but must have missed that tip about the diameter. Given that the diameter of the 'knob' is 22mm, then there must be 3.14 x 22 = 69 ridges on the outside of the knurled screw. If each ridge on the knurling tool is 1mm wide, then I don't see how one can be that specific about the diameter because the diameter of the 'peak' of the knurling tool is different from the 'trough'?
Next stage is to drill the sides of the plane and locate the lever cap in the right place - I need some serious commitment for that move!
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By Pete Maddex
#962627
Long series drill bit and go all the way through?

I guess that the circumference must have to be divisible by the circumference of the knurling wheel.

Pete
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By AndyT
#962661
I have only a tiny experience of knurling. I think I have done it about six times so far. I paid no attention to the diameter of the workpiece but every time the knurls lined themselves up into a "whole number". I think there must be something in the way that the pattern gets established then reinforced that makes this happen.
The only difference I can see is that I turned the work round slowly by hand. (My lathe is treadle powered. )
I used the same sort of knurler as you. Can you try some experiments turning yours by hand?

And I agree that using two diameters of brass is sensible and economical.
The lever caps sold by Bristol Design use a brass knob and a steel threaded rod so they agreed with you for the construction method.
By rxh
#962666
Your knurling looks good as far as I can see in the photo but if you are not satisfied you could turn off the the knurling and re-knurl, at the expense of ending up with a slightly smaller knob. I like to apply plenty of thickish motor oil when knurling, although some say that brass should be knurled dry. I have recently tried knurling by "hand cranking" the lathe rather than using a slow motor driven speed and the results were encouraging, which agrees with Andy's experience by treadling.

I'm not sure how much influence the relative diameters have on the quality of the result but I think what Andy has said above is plausible. My knurling tool has wheels of 51/64" diameter (20.4 mm) and I have used it with satisfactory results on brass of 1/2", 7/8" and 1 1/2" diameters.

Agreeing with Andy once more, I think your two part method is good. I have recently made a knob in a similar way and I applied Loctite as a precaution against unscrewing.

I like to cut small "steps" at the edges of the knurled area then remove the sharp edges slightly with abrasive paper - see photo below.
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By gasman
#962784
Thank you gentlemen - all very helpful. I had another go at the knurling last night - and I agree hand-knurling better and more controllable. It does seem to me that once you start knurling and the grooves appear, they reinforce each other and the cutters of the knurling wheel automatically move into those grooves - I would have thought you need to think about the diameter the smaller the diameter as then the percentage ratio will be greater so proportionally greater shift of the knurling wheel to stay in the grooves. Not sure if I was clear there - I knew what I meant! I also cut a groove so the knurled section is in 2 halves now - will post photos tomorrow
Thanks again for all help. Big weekend coming - infill time!
Best regards Mark
By gasman
#964968
My apologies for the delays in posting. The problem is my plane is last on the list of things to be done (in SWMBO's eyes anyway) so I keep getting jobs for the house to do. Since my last post I have made these
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which are beech kitchen stools copied from some we saw in Home & Garden. The tops are bits of kitchen top left over glued together then shaped
and this
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which again is copied from one she saw in a local Garden Centre. It is big - 2400 long. Finish is 3 coats danish oil. It is going to be outside covered in winter
So.. back to the plane.
I carefully drilled a 1/4" hole in the lever cap - I am going to be using 2 short 1/4" steel rods with a spring between to mount the lever cap so it is removable. I also have changed the screw slightly with a groove half way through the knurling which I think looks better
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Meanwhile I turned back to the damned infill and whether to use the figured, rapidly-dried beech. After Pete's helpful suggestion, I had bought David Charlesworth's Furniture-making Techniques: v. 1. and here is one of the relevant pages - it shows a much nicer looking rear handle (in my opinion) than the plans which came with this kit show - and I think I have enough beech to make it.
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I got a lump of old oak (left over from the bench) and made a rough version of the rear infill. The handle will be thinner and inserted into a recess in this piece.
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My beech pieces are pretty dry now - about 10% and I have this lot
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I sketched out a rough estimate of what the handle will be and where
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Then made yet another cup of tea and pondered whether it would all work - and then it was suppertime so finished for the weekend
More soon
Thanks for looking
Mark
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By gasman
#965449
Starting work on the rear infill
I finally stopped being such a wuss and cut the wood up
First was the rear handle - spent ages choosing how to cut it trying to avoid big holes and cracks
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The small cracks will be filled with a mixture of CA glue and sawdust from the same piece
Then started roughly removing the edges with rasps
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Using CA glue with fine sawdust to fill small cracks and stabilise the base of this handle which has a crevice in it!
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Finally this morning before work started with Abranet 120G
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Going to be a long slog but it is a real pleasure to do
Cheers
Mark
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By AndyT
#965468
Looking good - and you will end up with something bespoke which fits your hand. That's the sort of thing that makes the difference between an ordinary tool and the one you reach for first, though I suspect that the number of hours invested will always help favour the tool you made yourself!
By gasman
#965499
Thanks Andy
I have been 'umming and 'arring about whether to get a Norris adjuster for it. I think they do them at that place down the road from you? Bristol Design? What do you think?
Thanks Mark