Part 1 will cover general observations, trueness and repeatability
Costs (as of 12/2/16) Shipping & Taxes excluded.
Dorian - $57.35 (MSC)
Aloris - &62.70 (MSC)
Shars - $17.50 (Shars.com) $12.00 (ebay)
CDCO - $11.00 (CDCO.com)
Fit and finish wise the Dorian is the hands down winner. Very clean with almost no tool marks. Second is the Aloris with some tool marks and good quality bluing. The Shars and CDCO are a toss up. The CDCO holders look like they get handled roughly with nicks and dings and the bluing is of lesser quality. The Shars has a better appearance but the tool slot in the Shars holder looks like it was cut with a damaged cutter where the CDCO is much smoother.
Dorian - Very nice.
Aloris - Looks good
Shars - Outside looks okay but a bit rough in the slot where the tool sits.
CDCO - slot looks good but the outside is a bit beat up.
Here are the dimensions and general characteristics of each holder.
The Shars is the widest at 3.5", similar to the -XL holders by other manufacturers, followed by the Dorian at 3.25" with the Aloris and CDCO being both a little over 3". The CDCO holder appears to be an almost direct knock off of the Aloris.
Height wise the Shars, CDCO & Aloris are the same at 1.75" with the Dorian being much taller at 2.23".
Width wise the Shars is the thinnest at 1.145", the CDCO and Aloris are in the middle at 1.25" and the Dorian is the thickest at 1.5"
For the tool slot the Shars, CDCO & Aloris are all similar in height averaging about 0.66". The Dorian on the other hand is nearly 3/8" taller at 1". This becomes a problem on the my lathe (PM-1440GT) where the thumb nut bottoms out about 0.2" before a standard 5/8" tool holder can be centered requiring a 1/4" shim under the tool.
For the slot depth the Shars is the shallowest at 0.5" followed by the Aloris & CDCO at 0.55" and the Dorian at nearly 0.6"
The height adjusting thumb nuts for the Aloris and Dorian have a better fit and finish than the imports with the import thumb nuts having a looser fit. This comes into play when making a tool height adjustment. The looser fit thumb nut will move more when the lock nut is tightened causing the tool height to rise so it takes more trial and error to get the height set properly.
The Shars, CDCO & Dorian holders use height adjusting studs with hex key heads where the Aloris does not. I have had the studs come loose before when loosening the lock nut and the hex head makes quick work of re-tightening. It will be interesting to see if the Aloris ever comes loose.
The Shars & CDCO use a wavy spring washer between the thumb nut and lock nut. The Dorian uses an internal tooth-lock washer which I find annoying and not necessary as it digs into the thumb nut. The Aloris does not use a lock washer per say but instead uses a internal tabbed washer that fits into a key-way on the stud.
For adjusting the height I found the Aloris to be the easiest with little or no change in height when tightening the lock nut. The Dorian came in second with the fairly rigid lock washer and both the Shars and CDCO take more trial and error to get set properly due to the loose fit of the thumb nut.
The Shars and CDCO, being imports, have 10mm set screws. The US made Dorian and Aloris use 3/8-16 set screws. Quality wise I would say they are all similar with the Dorian & Aloris being slightly better than the imports. I have seem other import holders with terrible set screws that needed to be thrown away and replaced out of the box but I see no need to replace the Shars or CDCO set screws. I have used several CDCO holders for many years with no issues with the set screws.
The CDCO set screws use a 5mm hex key whereas the Shars, Aloris and Dorian use a 3/16" hex key.
For testing the trueness of each holder I first used an 0-4-0 Tenth's TDI to check the top of the cross slide as well as the top of the compound slide. Both showed no change in measurement through the full range of motion in the X-axis as well as the Z distance across the top of each. The QCTP was removed and cleaned and all mating surfaces were cleaned before measuring.
Each tool holder was then mounted on my Aloris BXA wedge type QCTP and a precision ground 4" vise jaw was mounted in the tool holder. I used the vise jaw because I had them ground a while back and know they are flat and parallel. It also provides a larger surface to measure.
The jaw was held forward in the tool holder to simulate the minimum projection of a common insert tool holder. Measurements were taken on top along the X & Z for parallelism.
From the results you can see there are three holders with nearly identical results. This tells me the QCTP has a slight tilt to it causing a 0.003" back slope. Assuming that to be true the only holder that has any error in the X-axis is the CDCO with 0.0037".
For the Z direction the Dorian was perfect and the Shars had the most tilt at nearly 0.006". The CDCO did better than the Aloris.
Next was the ability to repeat. Each holder was zeroed on the TDI, removed, re-inserted and re-measured 10 times. Measurements were taken at the top surface at the center line of the QCTP, the top at the simulated tool tip location and at the front edge.
The results below are the maximum deviation over 10 cycles.
While the Dorian performed the best the Aloris was a close second. The Shars and CDCO also performed very well with the maximum deviation being well within the tolerance of most hobby level lathes.
In Part 2 of the review I will test rigidity of each holder while taking cuts in steel and aluminum at different DOC's.