Dickson T1 tool holder

Does anyone know of a reasonably (read cheap) priced source for Dickson T1 (or S1) tool holders? Bigger than the Myford S00 size, smaller than the more common T2, they seem rare. Rotagrip do one **Link**, Bison at £61, I would like several so its a bit steep.

Thanks in fraternity

I can answer my own question - RDG have them (Sure I have looked before) £20 each.

( or £22.45 from RDG via fleabay)

Edited By simon Hewitt 1 on 30/11/2016 21:47:02

Out of stock at RDG. I am waiting for them to re stock.

Simon, the T1 toolholders are back in stock at RDG. I have ordered three, I will let you know how they fit when they arrive. If they prove to be OK then I shall order some more. Chris.

Also at Chronos normally. If the next size up from Myford ones they are often called Boxford size.

Simon, the T1 tool holders arrived today from RDG. They fit the Dickson post very well, only minor problems are the usual gritty threads requiring a clean and a few bruises on the securing screw squares. Excellent value I shall order a few more. Chris.

Thanks Chris. I ordered 2 from RDG and they seem fine, only used one so far, it works perfectly. I also ordered the extended pattern holder from Chronos, I slipped it onto the toolpost, it went down 2cm and got stuck, I needed a hammer to get it off again! The V slots were clearly about 0.5mm out, too far apart. I posted it back and got a refund immediately - but no comment from Chronos (Who I have used a lot and are generally excellent).

Perhaps the reason that patterns are quite rare is that they are very difficult to make?

Just make your own its not difficult

Mick h

There is quite a lot of confusion around the T1 sizing.

I have the original Dickson 73 square x 63 high on my M300. I also have a total of 17 holders mixed from standard to boring bar holders. The make of these are Dickson OEM, some Bison and a couple of Pratt. I recently bought the RDG T63 parting blade toolholder which actually dropped straight on my tool post.

I actually think there may well be two sizes of the T1 toolpost, both 73mm square but two different heights to match a couple of lathe variations in centre height. When you check availability from RDG there are two different slot widths listed for the T1 being 16mm ( as per Boxford sizing ) and 20mm.

All the ones on my Harrison are 20mm.

So, I suspect the 16mm are for Boxford ( they were 16mm on my previous Boxford ) and maybe earlier Bantam models sizing as the later Bantam 2000's had a bigger centre height.

20mm "T1" suits my Taiwanese 14"x40" copy of a Harrison M300. I have paid a lot of money for inferior ones and had to return them. RDG ones seem to fit well.

There are indeed two sizes of T1 post, sharing the holders. Data can be found here :

http://www.rotagriponline.com/datasheets/toolposts.pdf

These are as supplied by Bison, also available from Cutwel, no connection, just a satisfied customer of both.

There are also Imperial Dickson toolposts about...almost identical dimensions, but spares are not interchangeable without modification.

Good info

As Chris says, t.1 and t.1.x, identical except the height 2 1/2" (63.5 mm)
or 2 7/8" (73.025 mm). So I'm not sure about your comment on Imperial - I
think they are imperial! The counterbore in the post hole is 1.25" (31.75),
although the bore itself at 19.0 is 0.748, probably actually 3/4" ?

I saw RDG had 16mm or 20mm , I got 16mm to fit my largest tools, I don't
know if the 20mm are taller, which may make them a bit more rigid?
But i do find them very rigid, my insert type parting tool has quite a lot
of overhang but i still cut off steel bar under power feed. So no RDG have
them back in stock I am pretty happy!

The only problem I get is stopping them from rotating under very heavy
cuts, which I fix with a big 8mm bolt into a T-nut through a hole my post
has on one side. This stops me from rotating the post to get a better cut
angle (eg quick chamfering), so any advice?

A genuine Dickson post should have a second hole through the post fitted with a close fitting dowel post mating into a hole in the topslide. This, combined with close-fitting centre stud bushes should prevent turning enough for manual lathes. Since I'm using CNC, I can't allow any turning whatsoever, so I've fitted a piece of square bar to the topslide as an extra backstop against the tool post...no more problems so far.

The Imperial info came direct from Bison as I was needing a pair of new cam bolts. The spares currently supplied nearly fitted, but just needed a skim off the diameter to be able to fit into the toolpost holes. The hex size is also different from original.

Edited By Chris Hembry on 17/12/2016 19:01:41

Simon, are you saying the toolpost itself is trying to rotate on its centre mounting bolt whilst power parting?

If so, Is the mounting bolt fixed in thecompound slide or is it held by way of a sliding type of T Nut?

Wot he said. 17 so far and counting...

would a t63 toolpost be suitable for a mark 1 student? it a bit difficult getting information out of suppliers. rdg say that a t63 is suitable for bantams and chipmasters but is also suitable for lathes with 5 1/2 to 6" heights. but they haven't confirmed that it will be ok for a student despite contacting them. can anyone confirm either way? also i am sure i saw a comparison chart for the different sizes of QCTP but i didn't bookmark it and now can't find it again.

Paul

Sizing info here:

**LINK**

thanks