Member postings for JasonB

While others prefer to discuss the shape of their heads I found a bit of time to run the CAM for some cams. In the past I would either have used CamCalc with multiple offsets of the mill at angular increments around the cam or used the inside out boring head method particularly on cams like this with a flank radius. Both of which take a while to setup and in the CamCalc case a long while to cut.

This time with 0.4mm deep x 5.5mm high roughing passes and a slightly slower fed 0.2mm DOC finish pass on the silver steel the cam was done in 2.30mins with no need to do any blending with files after. I can't see me wanting to go back the the old ways of doing things.

Edited By JasonB on 21/08/2019 16:42:17

Think you need to read it again Barrie, Neil did not mention a National minimum.

Can we now keep the talk to the subject of Torx

As someone who can often get through a 1000 screws in a week it is quite usual to have the odd duff one or two with either poor heads or plain shanks without the screw part being formed Seem to remember the same thing with old Nettlefold screws as now with screws that I don't know where they are made. I Just bin the duds and get on with it.

That's not the model engineers way of doing things Clive, you know you should have spent the next three years contemplating making an EDM machine to modify your existing tools

Edited By JasonB on 21/08/2019 15:24:07

Another option as you are only going to be doing light punching would be to get some easily available 6mm or 1/4" hex mild steel and drill say a 4mm hole 25mm into the end and Loctite in some 4mm silver steel that has previously been turned to a point, hardened and tempered.

While you are at it make a matching dot punch which is used first to accurately place a small indent that can be pulled over to correct any drift before enlarging the mark with a centre punch.

This would still give you the practice with harder material, The hardening & tempering process as well as drilling holes. You would also have a usable tool at the end rather than a mild steel one that is no good to anyone.

Edited By JasonB on 21/08/2019 15:09:00

Edited By JasonB on 21/08/2019 15:21:07

With a few e-mails between Ketan, myself and David Corner who is able to place adds without having to get them approved we have now got a notice up on the site

~ = Approximate

This video shows the pump quite well, about half way through you can see that the ram lifts a little more than it's diameter so 1/2" stroke.

You only need to look at photos of other engines to see what the offset is, look at teh gear behind the eccentric, no way is it offset by 1/2"

Yes Jeff, altered it now

Drawing says ream 3/8" and shows ram as 3/8".

1" stroke does sound too much for that engine, he did use 1" stroke for the larger horizontal pump but 1/2" stroke eg 1/4" offset is more likely. By comparrison my 2" Fowler is 3/8" bore x 3/8" stroke.

Edited By JasonB on 20/08/2019 20:41:07

Does say "box of 5" and around £4 a go would be right for reasonable quality. You could also try APT who will sell you a box with just two inserts of a slightly better quality.

Can't say that I use my one of these cutters very much but do use grooving & profiling type with the 2mm dia end more.

A lot will also depend on material both type and diameter. Brass cuts easily but if too slender the cutting tool will deflect it and more chance of chatter. Stick out can also be an issue when clearance for the ball turner means the work is a long way out of the chuck.

Your 75mm figure would be if the whole insert were touching, at the most only half will be in contact so 37.5mm and even then as you get further around the tool the depth of cut lessens to nothing.

This form tool probably had a contact length of 30mm on my 280, stock is 16mm square

Biggest issue using a round insert as shown in teh video is the large fillet you are left with where the ball joins the stock which becomes proportionally greater as ball diameter decreases and the wide cutting action of the "blunt" round tip will put more load on the work needing a larger dia contact with the parent stock, an RCGT rather than a RCMT would help a bit as the edge is sharper as would going down to a 5mm dia insert to reduce fillet dia and contact length.

Edited By JasonB on 20/08/2019 07:26:24

You do not need to post any more to place adverts.

Check the bearing preload if you have not done it since fitting the new bearings and carry out the test on a warmed up machine.

Also take a consistant depth cut along the whole bar to eliminate changes in work, tool and spindle deflection

Yes should be able to get them from Blackgates though I know someone who has been waiting a while for them to get some of the Lincoln range cast, not sure about pumps and the corliss.

See page 94 & 95 here

Edited By JasonB on 19/08/2019 18:20:45

You get access to all the old MEWs for the duration of the digital subscription from No1 to current and it works on Windows.

Your subs expire 1st Nov so a few weeks notice is given.

Edited By JasonB on 19/08/2019 17:26:05

Thank's for the update Ketan, I have copied your post to Homeworkshop website where the subject was raised a couple of weeks ago and I responded then with the info you had already given me.

Edited By JasonB on 19/08/2019 16:57:00

One point that may have been missed is that when using a soft ctr held in the 3-jaw you true it up by taking a skim cut and then DO NOT remove it from the chuck until all work between ctrs is complete. By turning it before use you remove any errors that may have been there if the chuck runs slightly off and this can be more accurate than using a ctr in the spindle's Morse taper as that could be slightly off too.

That crankshaft I use to illustrate my first reply was taken in and out of the lathe several times as well as being swapped end for end but as I did not take the ctr out of the chuck all my turning will be concentric

Yes for slender parts that don't really need a lot of support you would not have to go right in with the drill and could stop part way up the 60deg part of the drill but you do need to go in past the smaller diameter pilot hole so that your ctr is bearing on a matching angled hole.

If the bar is too big to put through the lathe's spindle then yes a fixed steady or rest is used, this is one in action on something a bit bigger. You can also face the end of the bar with a setup like this as it is not good practice to start a ctr drill on a sawn end. Note as this was for a tool I have cut a small recess and then put the ctr drilled hole into that which saves the hole getting damaged which could throw things off.

Faceplates are more often used to hold odd shaped work that won't easily fir a 3 or 4 jaw chuck.

A drive or catch plate is a lot shorter than a 3-jaw chuck so allows you to get the max distance between ctrs as it does not protrude beyond the ctr mounted directly in the spindle

This size ctr drill would be durable, this smaller one is delicate and best kept for small work

Edited By JasonB on 19/08/2019 13:16:28