For parting I would highly recommend that you either make or acquire a suitable rear tool post. I am not familiar with the Boxford B or whether Boxford's ever produced a rear tool-post for it but they are easy enough to fabricate. You may find that mounting a parting tool in a front mounted quick-change tool holder may not give you a sufficiently rigid tool-holder as parting-off produces all sorts of problems, especially for a beginner with dig-ins and tool breakages etc. IMO you must always use copious amounts of cutting lubricant/coolant to assist successful parting. There is another thread somewhere on this Forum all about parting because we have just had a debate on it ad-nauseam so I won't begin to repeat the advice here.

Edited By Chris Crew on 26/04/2021 20:20:21

If yours still has what the Americans call a lantern tool post if you scroll down to the bloke in the white shirt you'll see the tool holder for it in use. Height adjustable and off centre like a QCTP you need one left one right and the parting tool holder.

+ 1 for Daves suggestion of retaining the lantern toolpost and using "Armstrong" type tool holders.

Although the lantern in standard form with conical washer and curved "boat" washer permitting the tool to be tilted for small height adjustment is widely disliked due to its tendency to move in about 64 directions simultaneously when the top bolt is loosened for adjustment simple modifications make it an inexpensive option for fixed height toolholders.

Basic idea is to replace the standard curved base washer with a flat one of suitable height and form a deep groove across it of the same width as the tool shank or holder body. This groove ensures that the tool cannot wiggle from side to side so it can be changed around. Although a milling machine or shaper is the best way to make the groove simply screwing a pair of plates to the washer at the appropriate spacing works well enough. Make the groove 1/4" (or more) deep.

Armstrong style tool holders hold short square tool bits, typically 1/4" or 3/16" for Boxford size machines, tilted upwards at a small angle. Hence the cutting tip can be bought exactly onto centre height by sliding the bit in and out so the actual holder can sit rigidly in the toolpost. The tilt up angle makes tool grinding easy and economical because the rake angle works well enough for most materials so only the tip needs to be ground. If the tilt up angle is too steep, eg for brass, it is easily reduced. Grinding the rake on conventional fixed tools is wasteful.

Carbide insert tooling is inherently fixed height so you just need to make the washer the right thickness.

basic Armstrong and equivalent holders from other makes such as Denford, Andycraft, J&S come in three varieties. Angled left for normal turning and facing with right hand tools, straight for grooving and threading, angled right for turning and facing with left hand tools. Right hand tool have the cutting edge towards the chuck side of the saddle, left hand tools towards the tailstock side.

You can also get boring bar holders, parting blade holders and threading tools. Threading tools carry a rotatable, part circular blade, with a flat top having the right angle, 55° for British or 60° for American and Metric, ground onto the periphery. Much easier to sharpen as only the top needs to be ground. The tool is rotated to set the tip on centre. Andycraft and Denford are the common UK breeds of these.

Parting blade holders tend to be the least satisfactory as they all suffer from more projection than desirable and use simple plain top blades needing a bit of practice to get the best out of them.

The modern T-type blade with hollow ground top is much better but only seem to come with holders having a side ledge to bolt into quick change or block type tool post. An adequate block type carrier can easily be fabricated by screwing and gluing together 3 standard steel bar sections. Similarly the Tee nut can be made form two more sections screwed and grooved together. Such a block post will work fine with the even better carbide insert parting tools. I'd make the block post with two grooves. The second side will be handy when branching out into the carbide insert world.

All much cheaper, but more work, than clicking "buy it now" on a QTP system.

If you do decide to go with an improved lantern it would be worth expending a bit of creativity on figuring out a way of preventing inadvertent rotation or sideways slide when loosening the bolt to change tools. I imagine a large belleville washer (basically a domed shape spring) underneath pushing against the bottom of the Tee slot would hold it nicely yet still permit movment when needed.

Clive

A QCTP is not a necessity. Also, be aware that holders form one make / type are unlikely to fit another.

Finding space to store the holders that i would be likely to use would be difficult in my small congested shop!

A four way post will serve equally well, and hold three tools (I have never managed to use all four slots! )

Tools can be adjusted to centre height by shims. Biscuit tines, or sardine tins tend be about 0.010" (0.25 mm ) thick. You can buy shim stock, if you need thinner, or cannibalise old feeler gauges. Aluminium, or card are not really suitable since they extrude when heavily loaded.

Setting tools to centre height is much easier if you make a Centre Height Gauge

(Look in my albums at the one that I made, why it has two blades will shortly become clear )

Unless the tools are set on centre height, they will not cut properly (if at all if above! , and will leave a "pip" in the middle of the work when the end is faced.)

For parting off, setting the tool to centre height is essential.

Parting off is MUCH easier if the tool is mounted, inverted in a rear toolpost.. My shop made four way rear toolpost carries a HSS parting tool, which is still in service, and has a lot of life left, after about 20 years of use.

Tools in the front toolpost are set to the underside of the upper blade, and tools in the rear toolpost are set to the topside of the lower blade.

Be VERY wary of mounting a parting tool inverted in the front toolpost and running the lathe in reverse.

With a screw on chuck, such as the Boxford and Myford, it can come unscrewed with the potential for damage to work, machine and yourself!

Carbide tipped parting tools cut beautifully, but a dig in means a new tip and a bill of at least £3.50, and possible damage to the holder, which may render it useless. (As I know to my cost! )

With regard to tooling, use the largest that will fit, with minimum overhang, it will be more rigid, and less prone to chatter.

I am not against carbide replaceable tips, I use them for roughing as well as for boring. But they don't like being banged, so intermittent cuts can chip them.

For machining hardened items, or breaking the skin on cast iron, they are excellent.

It has to be said that, in common with many others, a Tangential (Diamond ) turning tool is my weapon of choice for most turning and facing jobs. It easy to sharpen, having only face to grind, and is easily set to centre height, with the gauge.

When changing chucks, it is worth making a chuck board to sit on the bed of the lathe. Even a plain board will protect the bed if the chuck falls during removal or fitting. Better still would be to shape it so that the chuck is at the right level to screw onto the Mandrel. Because my 3 and 4 jaw chucks are different sizes, there is a loose piece of wood to bring the shaped piece to height for the smaller chuck..

If a chuck is stuck on the mandrel do NOT engage back gear to lock the mandrel while you unscrew it. You may well damage the gears! There are safer ways of slackening a stuck chuck.

You will get a lot of advice, some of it good, but conflicting, on here. (Already, you can see that we all have our particular hobby horses that we like to ride! )

Find a local Model Engineering Club and join, to be able to meet face to face (soon we hope ) . You may be able receive hands on help, and demonstrations.

HTH

Howard