Member postings for Kane

Thank you everyone, some interesting ideas.

Nobby, the reason I turned those jaws round was to have a flat surface against which the brass could be held. But as Andy states (and which makes sense now), this will only reproduce the surfaces I already have and so I wouldn't necessarily get truly perpendicular faces.

Andy, I like the sound of the angle plate idea, but I'm having a hard time picturing how I would clamp the brass to the angle.

Would it be as simple as using some G-clamps? Will these hold up to the forces involved?

Am I right in thinking, to get two initial faces perpendicular they would each in turn need to be held flat against the angle plate, and not against the faceplate? (But resting on the faceplate to provide support).

Thanks again,

Kane

Hi guys,

After sorting my QCTP out I can now begin on the task in hand.

As an exercise, I want to turn down a piece of brass bar (square cross section) so all sides are parallel.

This is what I have come up with so far:

Will this set up be sufficient to hold the work? Using some old tool bits as spacers. (The other jaws will obviously be clamped to the work too).

Are the 'faces' of the jaws (what the rear of the brass is sat against) flat enough to turn faces parallel?

Is machining each face in turn sufficient? I don't want to end up with a parallelogram sort of cross section.

Sorry for so many questions!

Cheers,

Kane

Well I ground the top of the tool down and that solved the problem.

Here are a few pictures of before (using the old broken tool post) and the new QCTP.

(Sorry about the picture quality)

Before: http://i.imgur.com/Yva51lh.jpg

This one looks like I have been trying to face it with a hammer. It was also pretty convex in shape.

After: http://i.imgur.com/ZUCvC5E.jpg

A nice flat clean face!

Edited By Kane on 29/03/2013 15:00:56

Edited By Kane on 29/03/2013 15:03:42

Great thanks Les.

If it's not a problem grinding the tool down further, I think this will be my first choice.

I do have a 4 jaw, but facing could be a problem without a toolholder haha. I was also concerned about how much it would weaken the holder.

Kane

Thank you everyone for your excellent advice.

I got hold of a 7/16" BSF nut and got the tool post mounted.

However I now have a problem with not being able to adjust the tool holder low enough to get the 3/8" HSS bit to centre height, as it bottoms out on the top slide.

I guess the best option would be to mill the bottom of the tool holder down, but without a mill this may be tricky? Are the holders usually hardened?

Is it possible to just grind the top of the lathe tool down further? It would need about 1-2mm taking off. Would this be ok?

I thought about buying some smaller (8mm) HSS blanks, but don't know if these will be too small for the holder.

Any advice appreciated.

Cheers.

Kane

Thanks everyone, I think I have all the info I need!

That bit of kit looks ideal Norman. I'll definitely have a go at making one, but first I'll need to secure the toolpost with a nut before I can make anything.

I would never have thought about adjusting the thickness of the washer, but makes a lot of sense. Looks like I have plenty to learn!

Cheers

Kane

Thank you Nigel!

One thing that confused me, the tool post came with a 'nut', it was like a cylindrical spacer with an internal thread, and a hexagon nut at the top.

This fits inside the central hole of the toolpost, but the thread was much too small to fit the stud in the top slide.

I thought it must just be a generic part that doesn't fit the myford (I emailed the manufacturer, but I don't think they will reply until next week).

Any ideas what it might be?

Thanks again for the quick reply.

Kane

Hi,

I have just bought a quick change tool post for my myford ml7, to replace a cracked 4 way tool post.

However the old 4 way tool post had a locking handle instead of a nut, and this will not fit the new quick change tool post.

Do I just need a standard nut to hold the QCTP in place?

I noticed the myford site sells the nuts with a spherical washer (which I'm guessing isnt required?), but £5 for a nut seems a little excessive.

Cheers guys,

Kane

Hi guys,

I'm looking to buy a quick change tool post for a myford ML7. I have come across quite a few posts praising the rdg tools quick change tool post, but has anyone any experience of the one from warco:

www.warco.co.uk/quick-change-tool-posts/209-quick-change-tool-post---90-115mm-centre-height.html

It looks awfully similar, but is £10 cheaper.

I'm also planning to try grinding my own from tools from HSS stock. Would 8mm or 10mm be preferable for these tool holders?

Cheers,

Kane

Hi everyone!

Quick introduction.... I got into model engineering around 10 years ago at the age of 15/16 with the intention to build a 5" gauge Simplex loco with only limited tools and a Myford ML7.

This progressed until the frames/stretchers/buffer beams were complete, but then came time to start machining components in the lathe. As you can imagine at this age, I had other things on my mind and so the completed frames have been sat on a shelf in the workshop for the last 10 years or so.

However recently I've had a renewed interest in model engineering and rather than diving straight in at the deep end again, I think it may be wise to take things a little more slowly this time around.

So I have decided on building a simple Elmers #25 Wobbler.

Today I dusted off the myford and decided to try a simple job of facing a piece of 3/4" square brass bar (how hard could it be!?)

I have seen articles of turning a round bar into a square, so I thought turning a square bar into a rectangle might not be so hard!

So I gripped the bar in the 4 jaw chuck and centered by eye as much as possible and made sure the tool was at center height...Away we go....

Nope... the top slide and crossslide were wobbling a good 2mm or so as the tool started to cut into the uneven (hacksaw) surface.

I wound the top slide off and cleaned the guide rails and tightened the screws up, much better.

First question:

Do the screws on the side of the topslide need to be tightened in a certain way to make sure the topslide moves parallel to the chuck face? Or are they just there to provide friction and reduce movement?

After facing the first side of the bar I held a steel rule up against the faced edge and it appears domed (convex), so placing it on a flat surface the bar wobbles. Is this due to wear in the lathe itself, or just a setting up issue?

I need to reduce the size of the 3/4" bar to 1/2" x 5/8" x 1-1/8" for the cylinder of the wobbler. Is facing the bar in this way a reasonable way to go about this?

I have a vertical milling attachment/slide for the lathe (but no milling tools) if this would be a better option?

If i continue with facing, how do I hold the remaining edges flat against the face of the chuck to keep them parallel, when the width of the material is not wide enough to protrude from the chuck jaws? Do I need to use some packing material that is already parallel?

After todays 'learning experience' the shopping list so far consists of:

A dial test indicator

A new tool holder (preferably quick change)

Some HSS tool steel to make some new lathe tools (or are pre ground ones preferable for the beginner?)

Any other essential items I should have?

I have The Amateurs Lathe - L.H Sparey and Using the small Lathe - I.C Mason, are there any other recommended books?

Sorry for the long post, I can't believe a simple facing job turned into so many questions!

Cheers,

Kane