You don’t need a slotting head to cut a splined sleeve, you can do it in the lathe with a slotting attachment, unless when you say ‘slotting head’ you actually mean a ‘slotting attachment’ which I take to mean a lathe accessory.

Please could you advise length of part. Something 30mm long is a different proposition to something 300mm long.

Providing it is short enough, at 8mm wide, some pre-drilling and plunge milling to remove excess material (preferably before forming the 21mm bore) would make an armstrong method on the lathe less laborious.

I am not sure it makes any difference, but OD of the part might be useful.

<p style=”text-align: left;”>I have cut a similar component in the lathe for a telescopic drive shaft with a slotting attachment even though I have the Tom Senior slotting head for the miller. It is not at all laborious and, if you have a lathe with a bull-wheel with a number of teeth that can be divided by four, you can use it to index the spline. Other than that, use a convenient change gear and detent.</p>

8mm wide is quite an effort to do on the lathe maybe OK if you split it into 8 cuts with a 4mm tool or ran a 4mm tool then an 8mm to remove the remaining 2mm each side of the first cut. Using the carriage handwheel would give you the 75mm without an issue.

The widest I have done is 3/16″ on the lathe

Yes done on the lathe but as you say quite a long process.  I held it in the 4-jaw with a simple spacer up from the bed to the side of a jaw to index. I’ve got broaches big enough to do them now.

“Do you happen to know of a published or commercially-available design that provides this length of stroke? The Hemingway one is silent on its capacity/dimensions.”

I made and used the Radford slotting attachment as described in ME and the book of his designs ‘Improvements and Accessories for your Lathe’ (TEE Publishing). Unfortunately, to the best of my knowledge, castings have never been commercially available for Radford’s designs, probably because many of them are not for beginners or the feint hearted. This is to be regretted, IMO, because you can learn so much when making them. I have had patterns made for me and also made patterns myself and prevailed on a local foundry to cast them. I quite accept not everybody would want to do this and, unfortunately, I sold the professionally made pattern for the slotting attachment a few years ago.

I assume this setup is what the OP was looking for; pity I’m in the perspiring dreams place:

And the finished gears with internal splines, top left:

The slotting head on the Bridgeport has a 4″ (100mm) stroke.

Andrew

Kind of surprised that no-one suggested using a shaper..  🙂

IanT

“What sort of width of slot can the Radford manage? I can’t find any online photos of a slotting attachment by him only a graduating tool.”

Without going down to the workshop to check, I think the splines on the telescopic shaft I made were approx. 0.250″. Of course, you have to take very shallow cuts, approx. 0.002″ – 0.004″, until you reach the desired depth and also work out any spring in the tool. I found that a piece of HSS tool bit silver soldered or brazed into the holder is better and far less flexible than a small piece of HSS held cross-wise in a MS holder. A piece of 0.125″ parting blade similarly silver soldered into place is good for slotting keyways.

Can’t seem to get any photo’s to load, sorry.