Milling on a Lathe with a Vertical Slide

[Andy CarlsonParticipant @andycarlson18141]

I thought it might be useful to write up my most recent job because it involved a lot of thinking and several different clamping arrangements. It is a 130mm long piece of dovetail bar to improve the attachment of my little 80mm telescope to my camera tripod. The dovetails are a 15 degree angle. Most of it was done on my 1930s Faircut lathe using my Tom Senior vertical slide. It would have been MUCH easier just to buy a short length of dovetail bar but in a fit of misguided enthusiasm last year I bought some 5/8 by 1 3/4 aluminium to make my own and then spent months agonizing over how to actually do the job.

Sorry no 'in progress' pictures because I didn't take any.

The first problem was the 15 degree angle. I have no tilting table and have never found one that I thought would be capable of useful work without also using up all of the available working space. Instead I decided to make two angle block fixtures that could attach using M6 Allen screws to the slots on the vertical slide.

They are made from the same bar stock. First I sawed a length off and then made a diagonal cut to achieve roughtly the right shape. A hacksaw is often much quicker than chewing metal off with a milling cutter.

Next the sawn ends needed to be tidied up. I did this on the vertical slide with the job overhanging the nearest edge and using the side of the cutter. I can't 100% remember but I think I used a steel strap over the job with a stud either side to engage with the 'T' nuts.

Next step was to drill the two 1/8 holes using XY coordinates to achieve an accurate 15 degrees. I could have done this on the vertical side but it has no dial so I used my little MF70 milling machine. The work was held down using step blocks and clamps… actually just one IIRC because there wasn't much room but I was only drilling so that was OK.

Then I milled the 15 degree faces. I attached a small vice (RDG Tools, no doubt from somewhere east of Suez) to the vertical slide, put 1/8 bar through the drilled holes so that the rods sat on the top of the vice jaws and clamped and milled both blocks together using the end of the 10mm cutter. Then remove them, mark and centre pop the middle of the 15 degree faces and return to the vice (still with the 1/8 bars), drill and tap M6. The final job was to mark out, drill and counterbore for the Allen screws (without the 15 degree tilt and overhanging the side of the vice to provide room for the drill to break through)

For the actual dovetails the first job was to mark and drill some M6 clearance holes – 1 3/4 will JUST fit in my vice on the slide. Then the angle blocks were attached to the slide, M6 studding screwed into the blocks and the embryo dovetail attached with nuts and washers. This was less than ideal because the dovetail bar prevented access to the Allen screws so it required some mucking about, clamping the blocks without fully tightening and then tapping them up or down to get the job level, checking level with a lever type DTI, then remove the job and tighten the screws… check again with the DTI to see if anything moved.

So now I could mill the angles using the side of the cutter on the top face. The big problem here is that even by winding the cross slide back (forward??) far anough to expose a short length of the cross slide dovetail at the rear I can get at most 4 1/2 inches of cross slide travel. I have a couple of 1 inch spacers that attach between the cross slide and the handwheel apron – those (and longer bolts) allow me to do the same trick in the other direction and get 5 1/2 inches of travel – theooretically enough for the job… if the job could be positioned to start and finish at exactly the limits… which it could not. I might have been able to arrange it if I had planned better but this is real life and that's not what happened.

My solution was to do each side in two operations, shifting the slide to another 'T' slot on the cross slide in between. This got the job done but there is a tiny step where the two cuts join – not an issue for what I needed but if I were making a dovetail whose main purpose was sliding then it would not be very good.

Job done. Telescope mounted. Naturally it has been cloudy and rainy ever since.

Edited By Andy Carlson on 03/05/2021 12:29:30

[Dr. MC BlackParticipant @dr-mcblack73214]

Posted by William Harvey 1 on 02/05/2021 18:45:31:

Posted by IanT on 02/05/2021 12:33:05:

Also found this in a search from Chronos (who I have bought some tools before – decent quality I thought)

Are you aware that using the Discount Code SME1000 will give you 5% off of Chronos' list prices?

MCB

[William Harvey 1Participant @williamharvey1]

Posted by Peter Baverstock on 03/05/2021 11:57:10:

Have a look at Steve Jordans videos on you tube,he has a particularly good set up for his chinese lathe.

Do you mean this drill attachment setup, does he do a video on the build?

https://youtu.be/GOxwuYacRv4

[Frances IoMParticipant @francesiom58905]

I’m awaiting just how the OP manages to hold a slide on the WM180 which has no Tslots not much meat to drill and tap a few mounting hole – the only way I can see is to mount it in the 4 way tool post and the reach of this along the slide is rather restricted and rigidity will be interesting.

I have a WM180 but I bought it after I bought a SX1 mill but even so having a couple of T-slots on the WM180 would have been useful for a couple of tasks.

[William Harvey 1Participant @williamharvey1]

Posted by MC Black on 03/05/2021 16:39:51:

Posted by William Harvey 1 on 02/05/2021 18:45:31:

Posted by IanT on 02/05/2021 12:33:05:

Also found this in a search from Chronos (who I have bought some tools before – decent quality I thought)

Are you aware that using the Discount Code SME1000 will give you 5% off of Chronos' list prices?

MCB

No I wasn't thanks

[William Harvey 1Participant @williamharvey1]

Posted by Andy Carlson on 03/05/2021 12:28:08:

I thought it might be useful to write up my most recent job because it involved a lot of thinking and several different clamping arrangements. It is a 130mm long piece of dovetail bar to improve the attachment of my little 80mm telescope to my camera tripod. The dovetails are a 15 degree angle. Most of it was done on my 1930s Faircut lathe using my Tom Senior vertical slide. It would have been MUCH easier just to buy a short length of dovetail bar but in a fit of misguided enthusiasm last year I bought some 5/8 by 1 3/4 aluminium to make my own and then spent months agonizing over how to actually do the job.

Sorry no 'in progress' pictures because I didn't take any.

The first problem was the 15 degree angle. I have no tilting table and have never found one that I thought would be capable of useful work without also using up all of the available working space. Instead I decided to make two angle block fixtures that could attach using M6 Allen screws to the slots on the vertical slide.

They are made from the same bar stock. First I sawed a length off and then made a diagonal cut to achieve roughtly the right shape. A hacksaw is often much quicker than chewing metal off with a milling cutter.

Next the sawn ends needed to be tidied up. I did this on the vertical slide with the job overhanging the nearest edge and using the side of the cutter. I can't 100% remember but I think I used a steel strap over the job with a stud either side to engage with the 'T' nuts.

Next step was to drill the two 1/8 holes using XY coordinates to achieve an accurate 15 degrees. I could have done this on the vertical side but it has no dial so I used my little MF70 milling machine. The work was held down using step blocks and clamps… actually just one IIRC because there wasn't much room but I was only drilling so that was OK.

Then I milled the 15 degree faces. I attached a small vice (RDG Tools, no doubt from somewhere east of Suez) to the vertical slide, put 1/8 bar through the drilled holes so that the rods sat on the top of the vice jaws and clamped and milled both blocks together using the end of the 10mm cutter. Then remove them, mark and centre pop the middle of the 15 degree faces and return to the vice (still with the 1/8 bars), drill and tap M6. The final job was to mark out, drill and counterbore for the Allen screws (without the 15 degree tilt and overhanging the side of the vice to provide room for the drill to break through)

For the actual dovetails the first job was to mark and drill some M6 clearance holes – 1 3/4 will JUST fit in my vice on the slide. Then the angle blocks were attached to the slide, M6 studding screwed into the blocks and the embryo dovetail attached with nuts and washers. This was less than ideal because the dovetail bar prevented access to the Allen screws so it required some mucking about, clamping the blocks without fully tightening and then tapping them up or down to get the job level, checking level with a lever type DTI, then remove the job and tighten the screws… check again with the DTI to see if anything moved.

So now I could mill the angles using the side of the cutter on the top face. The big problem here is that even by winding the cross slide back (forward??) far anough to expose a short length of the cross slide dovetail at the rear I can get at most 4 1/2 inches of cross slide travel. I have a couple of 1 inch spacers that attach between the cross slide and the handwheel apron – those (and longer bolts) allow me to do the same trick in the other direction and get 5 1/2 inches of travel – theooretically enough for the job… if the job could be positioned to start and finish at exactly the limits… which it could not. I might have been able to arrange it if I had planned better but this is real life and that's not what happened.

My solution was to do each side in two operations, shifting the slide to another 'T' slot on the cross slide in between. This got the job done but there is a tiny step where the two cuts join – not an issue for what I needed but if I were making a dovetail whose main purpose was sliding then it would not be very good.

Job done. Telescope mounted. Naturally it has been cloudy and rainy ever since.

Edited By Andy Carlson on 03/05/2021 12:29:30

Nice work and some great solutions.

[Mick B1Participant @mickb1]

Andy Carlson – another 'Nice work' from here. Your exercise also shows the thinking processes that the vertical slide encourages.

[Howard LewisParticipant @howardlewis46836]

If you want to cut valve seats, Sykes Pickavant used to sell them. Works OK in cast iron, but hardened seats tend to be harder than the cutters!

Grinding a toolbit to the required angle and using to produce the seat in one hit, without traverrsing (Nightmare process ) will ,take a lot of torque, and may produce chatter, since the single location in the valve guide will not be as rigid as needed.

Would suggest making the arbor as long as possible, and possibly split so that it can expand to suit the particular guide being used.s

Ideally, the seat and valve angle should differ by about half a degree, so as to produce a line contact near to the top of the seat. Valve and seat will probably hammer to match each other after a little running.

Howard

[Peter BaverstockParticipant @peterbaverstock32334]

Check your messages

Regards,

Peter.

[William Harvey 1Participant @williamharvey1]

Posted by Peter Baverstock on 03/05/2021 20:46:08:

Check your messages

Regards,

Peter.

Thanks Peter, read and replied.

[William Harvey 1Participant @williamharvey1]

Posted by Howard Lewis on 03/05/2021 18:03:30:

If you want to cut valve seats, Sykes Pickavant used to sell them. Works OK in cast iron, but hardened seats tend to be harder than the cutters!

Grinding a toolbit to the required angle and using to produce the seat in one hit, without traverrsing (Nightmare process ) will ,take a lot of torque, and may produce chatter, since the single location in the valve guide will not be as rigid as needed.

Would suggest making the arbor as long as possible, and possibly split so that it can expand to suit the particular guide being used.s

Ideally, the seat and valve angle should differ by about half a degree, so as to produce a line contact near to the top of the seat. Valve and seat will probably hammer to match each other after a little running.

Howard

Howard, don’t need to cut valve seats and I have a Neway Valve Seat cutter anyway. I need to cut a small recess around the top edge of the valve seat at 90 degrees to act as a reference point to grind the rest of the chamber roof to.

[William Harvey 1Participant @williamharvey1]

Posted by Andy Carlson on 02/05/2021 21:25:52:

Milling clamps… how long is a piece of string? Really depends on the job and your ability to problem solve. Certainly sthe type with studs, 'T' nuts, step blocks and so on are useful on some occasions but they are not the answer to everything. Sometimes you need studs and a piece of thick enough bar drilled to clear the studs to form a strap across the job. Sometimes a vice is best. Harold Hall's site has several designs of low profile clamps fo you to make. As others have said, sometimes you can co-opt the toolpost stud to help with clamping. The general rule is probably that you never quite have what you want.

One of the challenges of milling in the lathe is that you have a lot less free 'T' slotted (or whatever) space in which to put your clamps. Quite often I find that this precludes the use of step blocks. Gravity as another challenge – on a mill you can set up on the table at your leisure. With a vertical slide or angle block everything will fall off so you need to set up off the machine.

TBH I think that the many piece clamping sets are overkill – yes you get lots of bits but they are all of a similar type.

Start simple, take things slowly, learn what a healthy milling cut sounds like and how much 'demand' your setup can cope with. Be careful – I generally assume that a milling machine (or lathe doing milling) is always trying to damage itself, the job and/or me. Try to figure out how many ways it will find to trip you up – for example apart from flinging the job across the workshop the cutter can work like a corkscrew and either pull itself out of the holder and into the job or else pull the job in towards itself.

So without knowing what projects I am going to embark on I was hoping to by the parts to make a start to test the milling process.

I have opted on keeping things simple as you suggest and will be buying:

7" Angle Plate

A piece of 150mm x 125mm x 10mm Mild Steel to make the adaptor plate as shown in This Video at 4:57. Just need to find a supplier on eBay that will cut it for me as I don't have a band saw.

HSS Milling End Cutters – Any advice on what size cutters to start off with? I know this is dependent upon the task but this is just for testing? Or maybe I'll buy a cheap set 

I'll hold them in the 3 Jaw Chuck but will also make up a tool holder as mentioned, earlier

 

 

Edited By JasonB on 08/05/2021 16:01:34 See C of C

Edited By JasonB on 08/05/2021 16:02:19

[Dr. MC BlackParticipant @dr-mcblack73214]

When I did some milling on my Taig Lathe, I held the Milling Cutters in a collet. Have you investigated fitting a collet chuck to your lathe? ARCEurotrade (no connection – usual disclaimer) have some in their catalogue; one may be a direct fit on your lathe.

I appreciate it will take a long time, but have you considered cutting the plate with a hacksaw (or an electric jigsaw)

[Andy CarlsonParticipant @andycarlson18141]

Posted by William Harvey 1 on 08/05/2021 10:50:16:

So without knowing what projects I am going to embark on I was hoping to by the parts to make a start to test the milling process.

I have opted on keeping things simple as you suggest and will be buying:

7" Angle Plate

A piece of 150mm x 125mm x 10mm Mild Steel to make the adaptor plate as shown in at 4:57. Just need to find a supplier on eBay that will cut it for me as I don't have a band saw.

HSS Milling End Cutters – Any advice on what size cutters to start off with? I know this is dependent upon the task but this is just for testing? Or maybe I'll buy a cheap set of

I'll hold them in the 3 Jaw Chuck but will also make up a tool holder as mentioned, earlier

 

I havent looked at the link but I bought some cheap chinese HSS cutters and found them pretty poor – didn't last long and were not exactly to size so did not fit the correct sized holder properly. In fact it was one of these that taught me how cutters can work like a corkscrew. Now they are reserved to be reground as whatever oddball turning tools I might find a need for and held in a simple home made holder.

You don't need a lot of different sizes. For most work I had been using 6mm but have recently gone up to 10mm. My currently in use cutters are from Drill Service Horley. Obviously if you need to cut narrow slots then you will need smaller ones… or round nosed ones for fluting home made taps for but these should be reserved for jobs that really need them… and probably not bought until you know what you need.

 

Edited By JasonB on 08/05/2021 16:04:01

[William Harvey 1Participant @williamharvey1]

Posted by Dr. MC Black on 08/05/2021 11:52:59:

When I did some milling on my Taig Lathe, I held the Milling Cutters in a collet. Have you investigated fitting a collet chuck to your lathe? ARCEurotrade (no connection – usual disclaimer) have some in their catalogue; one may be a direct fit on your lathe.

I appreciate it will take a long time, but have you considered cutting the plate with a hacksaw (or an electric jigsaw)

I have been looking at EN25 Collets and a Collet Chuck but thought about getting it later. P.S. Sorry about the link, it sure why it came out like that, I thought I had embedded it.

[William Harvey 1Participant @williamharvey1]

Posted by Andy Carlson on 08/05/2021 13:51:55:

Posted by William Harvey 1 on 08/05/2021 10:50:16:

So without knowing what projects I am going to embark on I was hoping to by the parts to make a start to test the milling process.

I have opted on keeping things simple as you suggest and will be buying:

7" Angle Plate

A piece of 150mm x 125mm x 10mm Mild Steel to make the adaptor plate as shown in at 4:57. Just need to find a supplier on eBay that will cut it for me as I don't have a band saw.

HSS Milling End Cutters – Any advice on what size cutters to start off with? I know this is dependent upon the task but this is just for testing? Or maybe I'll buy a cheap set of

I'll hold them in the 3 Jaw Chuck but will also make up a tool holder as mentioned, earlier

 

I havent looked at the link but I bought some cheap chinese HSS cutters and found them pretty poor – didn't last long and were not exactly to size so did not fit the correct sized holder properly. In fact it was one of these that taught me how cutters can work like a corkscrew. Now they are reserved to be reground as whatever oddball turning tools I might find a need for and held in a simple home made holder.

You don't need a lot of different sizes. For most work I had been using 6mm but have recently gone up to 10mm. My currently in use cutters are from Drill Service Horley. Obviously if you need to cut narrow slots then you will need smaller ones… or round nosed ones for fluting home made taps for but these should be reserved for jobs that really need them… and probably not bought until you know what you need.

 

So I might just get a couple of decent ones and have a go.

Edited By JasonB on 08/05/2021 16:04:44

[William Harvey 1Participant @williamharvey1]

OK too much choice.

Chronos HSS End Mills – what is the threaded piece at the end for? I just want a straight shank to fit in the 3 jaw chuck?

Drill Service Horley Standard End Mill Cutters – which type do I get, too many unknown abreviations!!

[William Harvey 1Participant @williamharvey1]

Or Arc EuroTrade do HSS Tin Coated?

[SillyOldDufferModerator @sillyoldduffer]

Posted by William Harvey 1 on 09/05/2021 10:24:38:

Or Arc EuroTrade do HSS Tin Coated?

I have some ArcEuro cutters and they're good value.

My advice is not to worry too much. Any cutter will do provided it's in good nick. Just avoid very cheap.

What's unpredictable is whether or not milling on a lathe will allow decent cuts to be taken. Rubbing murders edged tools by causing rapid wear, and lathes set up to mill are at a severe disadvantage. Lack of power and especially rigidity force the operator to take light cuts, which are likely to rub. Although expensive cutters thus misused will last longer than cheap ones, it could be false economy. Save money by ruining cheap tools rather than expensive ones?

Best to understand milling on a lathe has multiple restrictions, including the possibility cutters won't last long. The advantage of milling on a lathe is it can be faster and more accurate than doing the same job with a file, but apart from that it's third-rate all round. Useful up to a point, but no further. Works reasonably on small objects but I found it so frustrating and limiting in practice I immediately started saving for a mill. Milling machines are truly wonderful in comparison because all the lathe imposed restrictions vanish.

The old guys often milled on their lathes and much good work was done. But it was only because most didn't have the space or money for a proper milling machine. It wasn't because lathe milling is a first-class way of munching metal.

Please let us know how you get on. Much depends on what you're doing and Mick's experience is more positive than mine.

Dave

[Martin ConnellyParticipant @martinconnelly55370]

Threaded cutters are for use in Clarkson, Vertex or similar tool holding systems but can be used in plain collets such as R8 or ER. If you don't need the threaded type they usually cost more than a plain shank because of the need to form the thread.

Unless you plan on making some threaded tool holders to hold onto the cutters best get plain shanks to save some money.

Carbide is very brittle and for someone starting out and using a lathe will probably not be good value as they can be snapped very easily and the edges chipped with ease. Your best bet will probably be plain high speed steel (HSS) and three flutes to start with.

Martin C

Edited By Martin Connelly on 09/05/2021 11:22:34

[Dr. MC BlackParticipant @dr-mcblack73214]

I inherited a lot of Milling cutters in various sizes, both Imperial and Metric, some with threaded shanks and some plain.

I hold them all in collets and they do the job.

Sometimes, "bundles" of milling cutters are offered on Ebay; it's a gamble as to whether they will be in usable condition but, bear in mind the cost of new from a reputable supplier and set your maximum price.

You could be lucky!

[Andy CarlsonParticipant @andycarlson18141]

FWIW the two I bought most recently were

SDFC3-10.00-S 10.00 HSCo Multi-Purpose Cutter Short
SDFC3-6.00-S 6.00 HSCo Multi-Purpose Cutter Short

They have 3 flutes and mostly plain shanks with a small cutout (but a collet etc will make no use of the cutout)

So far I've used the 10mm one several times on both aluminium and steel. The 6mm one has not been in action yet.

I went for the short ones because they stick out less… which may or may not help with rigidity a bit. On the other hand if you want to cut with the sides of the cutter then it is a disadvantage.

[Dr. MC BlackParticipant @dr-mcblack73214]

Posted by Andy Carlson on 09/05/2021 12:15:06:

FWIW the two I bought most recently were

SDFC3-10.00-S 10.00 HSCo Multi-Purpose Cutter Short
SDFC3-6.00-S 6.00 HSCo Multi-Purpose Cutter Short

Where did you buy these,please?

Clicking on them had no effect.

MC

[Andy CarlsonParticipant @andycarlson18141]

Posted by Dr. MC Black on 09/05/2021 12:53:05:

Posted by Andy Carlson on 09/05/2021 12:15:06:

FWIW the two I bought most recently were

SDFC3-10.00-S 10.00 HSCo Multi-Purpose Cutter Short
SDFC3-6.00-S 6.00 HSCo Multi-Purpose Cutter Short

Where did you buy these,please?

Clicking on them had no effect.

MC

Drill Service, Horley.

Sorry, I just copy/pasted from my order confirmation email. I didn't think to try to make anything clickable.

This is the page with all of the sizes on…

https://www.drill-service.co.uk/products/milling-cutters/standard-length-milling-cutters/sdfc3-hss-3-flute-slot-drill/

[William Harvey 1Participant @williamharvey1]

Posted by Bo'sun on 02/05/2021 09:14:13:

Good morning William,

Warco have a small milling slide that fits in the tool post which might suit your needs. But be mindful that it won't be overly rigid. They also have a base plate for the WM240/250 that takes a larger milling slide. It may be possible to adapt it to fit the WM180 cross slide.

I've had perfectly acceptable results from the milling slide on my WM250, it's just a nuisance to set up, and even more of a nuisance when you revert back to turning, only to find you still have another milling operation to complete. Also, compared to a milling machine, workpiece visibility can be a little restricted.

I’ve been in touch with Warco and they said they will be getting a Vertical Slide especially for the WM180.

in the mean time, when the need arises I’ll probably make up an adaptor plate (as shown in Steve Jordan’s video on YouTube) and bolt on a Angle Plate to attach work pieces to.

[Author]

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