Member postings for Ian P

The 'may' and 'might' can be eliminated with a thoughtful installation (or at least the travel loss can be minimised).

The link in Jason's reply shows an installation which does not lose any Y travel because it mounts the scale on the front of the table, however I would find that setup unsatisfactory because it has eliminated the use of the front edge of the table as a reference face and it also prevents machining work that overhangs the table edge. (I made brackets so that I could mount my Y scale below the table surface.

Ian P

I find its a very trial and error process.

I too touch off in a similar manner to Jason but I use the upper and lower points (north and south) on the screw or workpiece held in a Stevenson block and then halve the DRO readings to find the centreline. Apart from the fact that it difficult to see or feel when the sides of the slitting saw teeth touch the workpiece, I find most of my slitting saws have some wobble so results are not always as I expect.

I sometimes true up arbor faces and spigot diameters in the lathe and without removing the arbor from the lathe, fit the blade and still get runout at the saw teeth. I could probably reduce the blade wobble by having a large diameter arbor that only leaves enough of the saw teeth exposed for the depth I intend to cut.

I find that with, say a 1mm wide x 75mm dia sawblade with a 38 diameter arbour if there is any wobble the slot position partly depends on which part of the blade circumference make first contact and makes a channel for the rest of the blade teeth to follow.

Ian P

Most companies send out same day if they receive the order before a certain cut-off time, after that its all down to the delivery method. Large companies like RS and Farnell accept orders up to about 7pm and deliver next day.

I regularly used to order from a company in Warsaw who took orders up to 2pm, charged a fixed £7 for next day courier delivery and I was only let down once out of twenty or so orders due to a flight/airport delay. Unfortunately they no longer deal with private UK customers and for some reason they do not sell some of their products (even to account holders) in the UK. (Of course this has nothing whatever to do with Brexit!)

Ian P

Universal motors appear on angle grinders, vacuum cleaners, SDS drills and jack hammer things, I'm sure I have seen some rated well over 1kW.

Ian P

Whatever fixings are used to hold this disk to its hub, holding it to the hub is their only function.

I cannot see how there will be any shear forces involved. The disk will be subject to an insignificant amount shear force caused by angular velocity changes with engine RPM it will also have some wind resistance created by the notches in the periphery. The only reason for dowels of other locating methods might be to ensure timing repeatability (say after reassembly) but otherwise holding the disk in place with three small loctited screws is all thats really needed.

Just as an observation. The disk appears to be laser cut but looks more like SS than carbon steel, so I wonder if this for an optical sensor?

Ian P

Not really solving the problem but your woodwork looks to be to a very high standard but how did you make it without a workshop?

My thoughts on a solution to the diameter problem are that if the U channel really cannot be removed then reducing the diameter of the bent steel hoop by filing would be the best option. Even if its already painted then just file the 'sides' of the hoop so its ends up slightly oval leaving the upper paint intact.

You could use an angle grinder with a metal grinding (rather than cutting) disk to carefully widen the gap in the steel channel but it would need to be done slowly to avoid heating the metal (and therefore destroying the bond of your adhesive)

Ian P

How does this password book work?

Do you have to write in invisible ink or is there some other secret?

Surely putting all your passwords in one little book which is both steal-able and lose-able is not a good idea.

Ian P

As Mike said that is an odd type of cable, so odd that it probably does not exist.

Screened twisted pairs are usually used for signal wires rather than power cables, if you say what the VFD model is and the motor size someone will be able to answer the question easily.

Ian P

I have a thread gauge (bought in 1959) that has 'Whitworth 55deg' stamped into the side plate. the 26 different blades (4 to 62TPI) all have 'G' after the number.

As an example 12 TPI is marked 12G 1/2 9/16 but 13 TPI just has 13G (no diameter/s) as have 19G, 22G, 25G, 26G, 28G, 30G, 62G

I'm not sure what the G means at all really

Ian P

It is possible to identify a replacement belt in a situation where the tooth profile, the pitch, the width and the length are unknown but it requires a bit of effort. (jump to last paragraph for the easy way)

There are quite a few different tooth profiles and whilst they may appear similar picking the wrong one will significantly belt life. Manufacturers catalogues might show detailed drawings of the tooth profile but if the pulleys are fitted with flanges and the tooth profile is not visible then its hard to compare and decide.

I imagine that as Vic's belt is on a sander then it will probably not have any means of adjusting the pulley to pulley centre distance, therefore its essential to get the exact length of belt. one can work out the length if one can measure the pulley centres accurately but that is not always as easy as it seems.

Measuring the belt pitch by counting the number of teeth on a sprocket which you know the diameter of is straightforward, so in conjunction with centre to centre distances you can consult catalogues and most likely identify what will fit.

Far, far easier than measuring and guessing is just to Google spares with the product model number, most likely some of the results will include the actual belt manufacturers part number which you can then use to 'shop around' to find the best value supplier.

Ian P

Seven or so replies to Vic's question and nobody has given him the details of the belt he needs!

I wonder if its because we dont know the model number of the sander?

Since Vic already has a price for the belt then whoever quoted must have more info than we do.

Ian P

If the holes are much smaller diameter than the material thickness then presumably they will at least put a centre mark/divot so you dont have to mark out the positions.

Ian P

The laser cutting company (online quoting and ordering), I use has an online drawing editing feature that pops up if the DXF I submit contains any errors that might cause the cutting process to throw a wobbler. One can then correct small errors (or design simple parts from scratch)

The submitted DXF's must have all the cutting lines on one layer, must have no text or dimensions and all lines must be unbroken ie converted to 'polylines' (in Acad).

I send plain DXF files and do not need to state any units. When I first began using the company I put one major dimension in my drawing name but then did not bother because found that the website quoting software shows a little drawing of each part and states the X and Y sizes.

Online quoting means one can change material type, grade, thickness and other factors and immediately see the most cost effective method (where appropriate).

Ian P

Edited By Ian P on 29/05/2022 12:02:25

So what are the things we can do now we dont have the EU drones?

Yesterdays announcement about imperial measurements is really going to make a difference, not!

Ian P

A few observations based on the one picture.

It has an odd combination of features. Obviously the indicator and the part spherical objects are high precision but the chassis or frame of the thing do not seem to be in keeping. The indexable handle looks to be a budget diecast/painted item and the single visible hex--headed bolt looks to be the only fastening holding the narrowest ends of the slotted plates to the part carrying the handle, so the bolt would need to be very tight to prevent rotation.

I wonder what the 'tyres' of the two wheels are made from? they look more like mother of pearl than some engineering material!

How many of the part spheres are there and do their bores tie up with anything on the device (like thread or bore size)

Ian P

I suspect the most likely cause of the chattering/rough finish is most likely due to the chuck not gripping the workpiece firmly enough. The slightest amount of bell-mouthing (or the reverse) of the chuck jaws would have the effect of only gripping firmly at one narrow axial position along the bar rather than over, say, 30mm of its length.

Ian P

For anyone with Sky catch-up (or whatever it would be called) I can recommend a programme I saw yesterday evening on Sky Arts, Channel 11 on Freeview.

Programme was called 'Journey into Infinity' and its about MC Escher who must be the worlds master on tesellation.

Ian P

How does hardening silver steel increase its diameter?

Ian P

I dont have any way of rolling my own rings (or any way of milling a 400mm diameter ring!) so will make enquiries at the two companies suggested.

Ian P