Making a large washer.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Justin, just set it up in your four jaw as JasonB has shown and cut the hole with your 36mm hole cutter, but make sure there is a clearance so your cutter doesn't make contact with the chuck jaws when it breaks through, then bore it out to size, and proceed in the same way as said and shown to trim the outer diameter to size.

Regards Nick.

[Justin ThymeParticipant @justinthyme24678]

Thanks for all the replies, I do read them all with great interest.

I think I'm going to go with JasonB's post above. We do have a large 4 jaw chuck and on the small lathe the chuck is small enough to grip the inner hole of the work piece.

[not done it yetParticipant @notdoneityet]

Before I had a lathe, I made several large washers, over a few years, by use of a “Practool”. It has largely fallen out of favour since, but might still be useful for cutting large holes in sheet metals in the field.

[CirclipParticipant @circlip]

Surprised no one has mentioned the 'Tank Cutter'

Regards Ian.

[Clive FosterParticipant @clivefoster55965]

Circlip

The tank cutter tool is basically a trepanning cutter for making holes in well supported sheet metal. Not so good with two concentric holes.

I have one and it hates me!

We have agreed that if I leave it resting in the drawer it won't take bite out of me letting the red stuff out!

Clive

Edited By Clive Foster on 13/06/2023 09:27:30

[noel shelleyParticipant @noelshelley55608]

Yep ! I have a tank cutter, eclipse I think. Never used. Not sure it would go the O/D needed here. Noel.

[Justin ThymeParticipant @justinthyme24678]

Got a start on it today, as ever, it didn't quite go according to plan. As you can see the slide thing (whats it called?) was in the way and too big to go under the chuck, and this meant that I could not get the tailstock any where near the work piece. I could have removed the top part of the slide thing so as to get it under the chuck, but it seemed like a lot of effort. What should I have done ?

So what I did do was drill out the centre holes on the pillar drill, here I was very luck, the hole saw is supposed to be 36mm, but our hideous pillar drill is so unconcenteric (is that a word) that the hole turned out to be very nearly 39mm, a little bit of work with a file and it was perfect.

The other prob that I encountered (and I'm hoping for a bit of advise) I tried to put the plate after the 39mm hole was created, but just could not get it centred, I have one of those dial things for checking concentricity, but couldn't set it up on the inside of the hole.

[Martin ConnellyParticipant @martinconnelly55370]

Cross slide.

I often use a morse taper extension in the tailstock for this reason. MT2 to MT2 for my lathe. It's often said you need to spend more on tooling than on the machine. The current discussion on QCTP Vs. 4 way tool post, for example, mentions cost being significant. This extension may be one more thing you will need at some point.

Martin C

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Justin, don't you have a self centring three jaw chuck as shown in JasonB's second photo?

Regards Nick.

Edited By Nicholas Farr on 18/06/2023 06:58:06

[JasonBModerator @jasonb]

Could you not have held it by the outer step in the jaws? That would mean none stick out beyond the body of the chuck, might need a bit of packing if the jaws meet in the middle before they tighten onto the work

As for clocking the hole true. I did show a 3 jaw which will not really need clocking unless it is well out or you are after high accuracy. If using the 4-jaw with a thin piece like this you could put the dti onto each jaw face, when they are true the work should be too. Thicker work can be done by initially gripping half the depth of the work so you have an uninterupted surface to run the dti on then move it back for machining

[not done it yetParticipant @notdoneityet]

I am needing to form what can best described as a large washer out of 3mm mild steel late.. 39mm dia centre hole, with a 89mm outer edge.

I am suspecting that ‘(p)late’ is actually 5mm, not 3mm? I’m certainly hoping it is not two unattached pieces measuring a total of 6mm! That could be positively dangerous!

If two pieces, please securely fix them together before machining.

Drilling/boring and affixing to an arbor might well allow clearance over the cross slide, if those corners were sawn off or removed with an angle grinder.

[OldironParticipant @oldiron]

The "slide thing" that runs end to end on your lathe is called the "Carriage". The "slide thing" that runs on the carriage across the lathe is called "the cross slide" IHTH. This LINK will let you download a copy of the "How to run a lathe" book which will give you a lot of usefull info although a little outdated most of it still applies today.

regards

[Justin ThymeParticipant @justinthyme24678]

Posted by Nicholas Farr on 18/06/2023 06:54:47:

Hi Justin, don't you have a self centring three jaw chuck as shown in JasonB's second photo?

Regards Nick.

Edited By Nicholas Farr on 18/06/2023 06:58:06

Yes, but they don't take square bits, and even if I rounded the outside first they would not be big enough.

[Justin ThymeParticipant @justinthyme24678]

Posted by JasonB on 18/06/2023 07:02:38:

Could you not have held it by the outer step in the jaws? That would mean none stick out beyond the body of the chuck, might need a bit of packing if the jaws meet in the middle before they tighten onto the work

As for clocking the hole true. I did show a 3 jaw which will not really need clocking unless it is well out or you are after high accuracy. If using the 4-jaw with a thin piece like this you could put the dti onto each jaw face, when they are true the work should be too. Thicker work can be done by initially gripping half the depth of the work so you have an uninterupted surface to run the dti on then move it back for machining

Yes it was too small for the outer jaws, packing would have seemed a bit precarious.

As for the centring of the hole, this, by luck was not necessary, however I was curious if I could have centred it, had I need to enlarge or improve the hole – something I may need to do in the future.

[Justin ThymeParticipant @justinthyme24678]

Posted by not done it yet on 18/06/2023 08:24:32:

I am needing to form what can best described as a large washer out of 3mm mild steel late.. 39mm dia centre hole, with a 89mm outer edge.

I am suspecting that ‘(p)late’ is actually 5mm, not 3mm? I’m certainly hoping it is not two unattached pieces measuring a total of 6mm! That could be positively dangerous!

If two pieces, please securely fix them together before machining.

Drilling/boring and affixing to an arbor might well allow clearance over the cross slide, if those corners were sawn off or removed with an angle grinder.

Indeed it was two 3mm plates. In what way could it be dangerous, it seemed very secure.

I'm sure I would be soon aware if there was any looseness, and once the hole saw was engaged then the work piece would be trapped between chuck and tail stock ?

[HopperParticipant @hopper]

Posted by Justin Thyme on 18/06/2023 10:29:51:

Posted by Nicholas Farr on 18/06/2023 06:54:47:

Hi Justin, don't you have a self centring three jaw chuck as shown in JasonB's second photo?

Regards Nick.

Edited By Nicholas Farr on 18/06/2023 06:58:06

Yes, but they don't take square bits, and even if I rounded the outside first they would not be big enough.

If you look at Jason's pic, the three-jaw chuck is holding the job by the round hole in the middle. But you need to have the reverse jaws for your 3-jaw to do this.

Otherwise, you could put a piece of round bar in the chuck, turn a step down on the end to fit in the hole in your plate, then drill and tap a hole in the middle and use a bolt and large flat washer to hold the job in place. Known as a stub mandrel or arbor.

You will save some grief by hacksawing the corners off your square before machining it round.

And please do follow Oldiron's link above and download the book. Life will be so much easier if you know the basic terminology and procedures. It is a great old book and still relevant to day. Turning is turning.

Edited By Hopper on 18/06/2023 10:54:01

[Justin ThymeParticipant @justinthyme24678]

Posted by Hopper on 18/06/2023 10:52:04:

Posted by Justin Thyme on 18/06/2023 10:29:51:

Posted by Nicholas Farr on 18/06/2023 06:54:47:

Hi Justin, don't you have a self centring three jaw chuck as shown in JasonB's second photo?

Regards Nick.

Edited By Nicholas Farr on 18/06/2023 06:58:06

Yes, but they don't take square bits, and even if I rounded the outside first they would not be big enough.

If you look at Jason's pic, the three-jaw chuck is holding the job by the round hole in the middle. But you need to have the reverse jaws for your 3-jaw to do this.

Aye, but I needed to create the hole in the plate first, I was wishing to do this on the lathe. I had wanted an excuse to use the 4 jaw chuck.

Now the hole is created (on the pillar drill) I can move on to the three jaw chuck to form the outer edge. (and yes I can soon get it into reasonable roundness with the angle-grinder before machining on the lathe

As for downloading books, I got a box full of books along with the lathes, I find books hard going for some things. and was hoping to ask things not easily found in reference books on here. For instance, as I asked earlier, would removing the cross slide so as to do a job be a common practice. I didn't think it worth the time and effort for this job, but would that be something others would consider or would it be a big No No.

[Speedy Builder5Participant @speedybuilder5]

I think you meant topslide Justin. This would give you more rigidity of the cutting tool BUT you would need a special spacer to get the tool up to the centre line and your cross slide would need 'T' slots or a tapped hole to attach the tool post / spacer to. I have never bothered doing it.

Bob

[HopperParticipant @hopper]

Sorry, I thought you had made the hole and were now asking about the outside.

Yes books can be hard going. But using a lathe is harder. So well worth the effort to sit around and browse a few of the former in order to make the latter easier.

No it is not common to remove the cross slide because then you have nothing to mount the tool on and no way of controlling its depth of cut. But needs must and you could remove it for clearance if you needed to move the carriage under the large chuck so you could bring the tailstock up closer, if it would fit.

 

Edited By Hopper on 18/06/2023 11:31:49

Edited By Hopper on 18/06/2023 11:33:06

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I believe Justin only wanted to remove the cross-slide etc. to be able to move the carriage closer to the headstock, so that his tailstock would be able to get close enough to be able to reach with his hole saw to cut the virgin hole in the first place. However, if the cross-slide nut that can be seen in his photo doesn't come out easily, the carriage may still not pass below his chuck jaws without hitting it.

Regards Nick.

[not done it yetParticipant @notdoneityet]

Posted by Nicholas Farr on 18/06/2023 12:01:48:

Hi, I believe Justin only wanted to remove the cross-slide etc. to be able to move the carriage closer to the headstock, so that his tailstock would be able to get close enough to be able to reach with his hole saw to cut the virgin hole in the first place. However, if the cross-slide nut that can be seen in his photo doesn't come out easily, the carriage may still not pass below his chuck jaws without hitting it.

Regards Nick.

How about removing tailstock, crank carriage to far end of bed and replace tailstock in front of carriage? If it will fit, that is.

[Justin ThymeParticipant @justinthyme24678]

Yes Nicholas, that is exactly what I was going to do, there would have been plenty room with the cross slide off, but I would have need to form a bit of plywood to protect the base from dirt, fillings etc, then would I need to readjust the gibs when reassembling, seemed like a lot of work , so did'nt bother. But it certainly could have been done if it was important, and this isn't.

Anyway, moving on.

I now have the two squarish plates with a 39mm hole in the middle. I now need to create an outer edge of 89mm dia concentric to the inner hole, and also 4 evenly spaced 8mm holes 35mm from the center.as per this 3d printed one

The plan is to mount it into the chuck as per JasonB's earlier picture

My plan is to then score two circular marks, one with a dia of 70 and the other 89mm.

The 70 mm dia line will allow me to mark out and drill the four 8mm holes

and the 89 mm dia line will be a guide to cut and grind down to before remounting the piece in the chuck and precisely turning it down to 89mm

But how do I accurately measure the two circles, how will I work out where the exact centre is? The smaller lathe has a digital readout, but how do I zero this? Should I start off with another piece of round bar and establish a zero point off that – or do I simply score a ine at say roughly 95mm, then if that measures manually at 94.7 would I use that as a ref and work from there.

There is room on the chuck, so do I turn them at the same time ? should I hot melt glue them together, or may if there is enough room, drill the holes first and bolt them together. ?

[Nick WheelerParticipant @nickwheeler]

Were the four bolt holes in the original request?

Because they change how you make the part:

Start with a piece of stock big enough to create the piece

Mark the centre of all three(centre hole, outside edge and PCD) circles.

Draw the centre and outside edges with dividers.

Mark out the PCD.

Drill the PCD

Bolt the piece to a (sacrificial)faceplate using the PCD, and ensure it runs true to the centre mark

Machine the inner and outer edges.

 

You make several pieces by bolting them to the faceplate at the same time

 

Edited By Nick Wheeler on 18/06/2023 13:32:39

[JasonBModerator @jasonb]

Put a light mark in one place with a turning tool held in the toolpost, rotate chuck 180deg and put another light mark. Measure the distance between the two and adjust and repeat until you get the 70mm one. Wind out the cross slide by 9.5mm and than you can mark the 89mm line

Alternative is to measure 25mm out from the edge of the hole to get your 89mm mark and then wind in 9.5mm to do the 70mm

[not done it yetParticipant @notdoneityet]

Could any of this be done on a lathe or milling machine ?

It could all have been done on a milling machine. Including the holes.

What is the required precision of this part? Like, would clearance holes be adequate?

If you have a mill (and neither rotary table nor dro), someone could easily obtain the coordinates for the holes from their own dro. Altenatively, using self-help, finding the coordinatesfor those holes is a fairly straight-forward operation.

[Author]

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