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Member postings for JasonB

Here is a list of all the postings JasonB has made in our forums. Click on a thread name to jump to the thread.

Thread: [Project 3] Dickson T1 Tool Holder
24/05/2020 19:26:47

Those insert cutters won't work as you need to get down into the bottom of the Vee, you need something that goes almost to a point if using an angled cutter.

A few suggested a shaper for these types of jobs, this popped up on my Youtube today which you may enjoy.

Edited By JasonB on 24/05/2020 19:29:13

Thread: Exhaust port
24/05/2020 12:19:56

Fromn another piston/spool valve engine

danni 1.jpg

Steam or air comes in from the central inlet and the position of the valve piston sends it to the port at the top of the drawing which goes into the cylinder and pushes the main piston down.

Spent steam or air on the other side of the main piston is ttherefoer pushed out the port at the bottom of the drawing, through the drillings and the valve piston directs it to exhaust

Edited By JasonB on 24/05/2020 12:21:11

Thread: New Mill - Starter Tooling
24/05/2020 10:32:39

You can get 5C to ER25 adaptors that would allow a spindexer to take Er25 without too much overhang.

Thread: Myford S7 Cutting Barrel Shaped Cylinders
24/05/2020 10:19:24

"It’s a worn lathe, giving ‘worn lathe’ performance."

Agree with that Michael

Advantage of the bobbin type test is your tool stays nice and sharp doing two ( or 3) 1/4" wide cuts so giving a more consistent reading than turning a whole long length. You can also make it with "rings" loctited to a shaft and keep that for testing setup and simply heat the rings off when too small and fit new, saves wasting lots of bar.

Even using a between ctrs test piece could be a problem if the tailstock had droop or wear to match that of the bed, one of the downsides of buying old machines I suppose.

Edited By JasonB on 24/05/2020 10:20:22

Thread: Source for small scale Aluminium chequered plate
24/05/2020 10:10:23

Southworth used to do 1/10th and 1/16th scale chequer plate but like their engines it is now available from Blackgates which would probably be closer to scale than the trainset stuff.

Thread: Myford S7 Cutting Barrel Shaped Cylinders
24/05/2020 07:18:09

With upto 5thou wear in the bed how useful is an accurate level going to be as you could be resting on a worn surface one end and almost untouched at the tailstock end?

In a similar way although a test bar will give you a reading with zero force against the carrage if there is wear in the bed there is also likely to be some in the cross and top slides and any cutting force will push the tool away unlike the weak spring of a dti that just follows so unlikely to get two matching results. Hold dti in the tool post and pull the toolpost back while dti is resting against side of test bar.

If you are getting a barrel then do the bobbin test but with a 3rd large diameter piece in the middle, light cut first as Gray suggests then a heavy one to see if things change due to forces pushing the tool away.

Edited By JasonB on 24/05/2020 07:48:12

Thread: Machine Stalls and Observations
24/05/2020 06:55:01

An idea of what machine you are using, what you call a "deep cut" what feed rate (hand or power? ), diameter of bars would help. Also is the motor stalling or just the chuck and the belt slipping.

Thread: Stuart 10V Build Log - Complete Beginner...
23/05/2020 20:43:49

For small beaings and such parts like this your arbor or mandrel can take many forms.

1. Most simple is to put a piece of bar into the chuck and turn to a good firm fit in your bearing and then slip the bearing on with a small amount of loctite or superglue, once machined heat will break the bond. The downsid eto this method with four ends to do is that you have to remove the mandrel each time to heat, it can be marked so it goes back in the same way but not ideal to remove it.

2. Similar to above but turn the spigot that fits into the hole about 2/3rds its length but put a very slight say 1 deg taper on the rest so the diameter increases towards the chuck. You can then slip the bearing onto the parallel part and then wring it onto the taper with a slight twisting action, if light cuts are used it will hold and the part can be wrung off again so mandrel stays put ensuring it's concentric.

3. Again turn a spigot to a good firm fit in the bearing and just shorter than it then drill and tap the end for a bolt or screw to retain the bearing, M5 with a cap head screw would work nicely on these bearings as screw head is just under the diameter you want to turn. Again mandrel does not need to come out of chuck. I'd go with this option.



4. Turn spigot to full length or a bot longer, drill and tap with a taper tap so you get a few full turns of thread. Mark the bit of bar you are using so it can be removed from chuck and then saw down the middle of the spigot before putting back in chuck. You can now slip the bearing onto the spigot and wind in a screw which will expand the spigot as it gets to the tapered part of the thread.

I tend to use aluminium for these sort of things and you soon build up a collection that can be used again and again, maybe skimming down to the next size or shortening.

Thread: Mild steel wheel blanks
23/05/2020 18:46:40

A lot of the laser cut stuff is S275 which is not the nicest stuff to machine, better suited to teh welding and fabrication guys than machinists, it also has a slightly higher carbon content (0.25% ) which may be what the heat is affecting. The other downsid eis it is a hot rolled steel and does have a thin smooth coating of mill scale, not so much black but a dark silvery grey which can be hard and abrasive to tools.

If getting stuff laser cut then ask for HR4 which is hot rolled so no scale and about 1/3rd the carbon content. Still not a snice as a slice of 230M07 though

Edited By JasonB on 23/05/2020 19:01:09

Thread: DRO error
23/05/2020 07:11:45

I would tend to enter 4No holes start at 0, end at 270 for ones at right angle to the axis, if diagonally placed then 4No, start at 45 and end at 315.

There is an alternative which is to enter 5No holes start at 0 and end at 360

Thread: Internal threading question
23/05/2020 06:58:32

I did have a measure of my 10mm one but it has the 10mm shank all the way and I only have a partial form 0.5-1.5 insert so could not really give an exact answer but it did fit into a M16 nut with plenty of room to spare.

Thread: Mild steel wheel blanks
22/05/2020 18:39:32

If you have enough spar on diameter you can run the edge against a linisher/belt sander or even use an angle grinder. If the flat surfaces have mill scale on them I'd also suggest an acid dip.

Thread: [Project 3] Dickson T1 Tool Holder
22/05/2020 18:35:31

Block of metal you are making the holder from.

Maybe quill could elaborate on his holding methods.

Thread: WAHYA ME 4639
22/05/2020 14:00:30

KWIL, did no one ever tell you looking at too many centre folds would make you go blind?

I've only got the digital at the moment and that is finesmiley postie not been yet.

Thread: A polite question - from a beginner :) Drilling a NONE wandering hole
22/05/2020 13:42:38

Not that conclusive on your link Michael, though I have not read it all.

"The spot drll point angle should be greater than or less than the final drill’s point angle."

Anyidea what they mean by:

Using  a spot drill with an angle less than the drill point angle WILL cause the drill flutes to be "blown off"

Edited By JasonB on 22/05/2020 13:45:03

Thread: Stuart 10V Build Log - Complete Beginner...
22/05/2020 13:14:32

It's not critical just whatever you have, I've made a sprung one which stays in place a bit easier but plain will get you started.

Thread: [Project 3] Dickson T1 Tool Holder
22/05/2020 13:12:50

You just need to see how much it moves when you tighten it down and then set it to compensate.

Thread: Drilling brass conumdrum
22/05/2020 13:10:51

Andrew, by sharp I meant not worn, I'm sure your zero rake drills would not perform if the actual cutting edge had become worn and rounded

I'd don't stone my drills or keep a special set, if enlarging a hole then I will add some drag from the tailstock lock if on the mill or feed using the handwheel on the mill not the lever feed, which seems to stop the problem.

Thread: [Project 3] Dickson T1 Tool Holder
22/05/2020 12:43:18
Posted by Lee Jones 6 on 22/05/2020 08:21:14:

How does 0.1mm over 480mm sound?

As nobody else has answered from last night I get about 1/10th of that in X&Y eg 0.003mm in 140mm on a Chinese machine.

Thread: Stuart 10V Build Log - Complete Beginner...
22/05/2020 12:39:45

yes, definately cut in half and treat as two items for initial work, back in the day a 1/64th" smaller drill would have been the most likely used, I'd most likely reach for 6.9 or maybe 7mm with the 6.9 being first choice as a drill can often cut oversize. Once upto 8mm hole I tend to bore on the lathe rather than ream so drill wander is eliminated, you could just about bore to 7mm if you have a small bar.

The other option would be say drill 5mm, put a 6mm or 1/4" milling cutter through held in the tailstock which will true up your hole and then follow that with your reaming size drill that will then have a straight path to follow.

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