5C collet D-bit Grinder

[PeterT]

I'm too lazy to go hunting but seems like someone on the forum mentioned they have the (likely Shars) 5C collet based D-bit grinder. Who be you?

Universal End Mill Cutter Drill Bit Grinder Sharpener

www.shars.com

I'm interested to confirm the dimensions of the dovetail on work head & flute attachment, which should be the same.
Also, I assume the threads of tightening arbor on the work head engage the inner 5C collet threads?

 

[140mower]

I'm too lazy to go hunting but seems like someone on the forum mentioned they have the (likely Shars) 5C collet based D-bit grinder. Who be you?

Universal End Mill Cutter Drill Bit Grinder Sharpener

www.shars.com

I'm interested to confirm the dimensions of the dovetail on work head & flute attachment, which should be the same.
Also, I assume the threads of tightening arbor on the work head engage the inner 5C collet threads?


View attachment 38447View attachment 38448

....... Looking forward to hearing the replies, it would be a cheap(er) solution to the collet issue I have with mine....

 

[Former Member]

1.055" Dovetail widest point.

Both inner and outer depending on which head for the 5C

 

[PeterT]

Thanks. At some point I'll start a post on my (Accusize) R-8 D-bit grinder. Right now I'm at early steps of getting up to speed. The Shars 5C workhead was out of stock for the longest while, came back in recently, hence my question. Its a bit spendy but I weighed the pros & cons of what I have (full progressive set of 5C's) & things I want to do with the machine. The somewhat annoying issue is the (yellow) work head comes complete with (green) lower swivel attachment which I'm confident is the same & likely explains a chunk of cost but oh well. If I like it more I'll swap it too. I also have the 5C spin head coming, that is just a standalone chunk.

Getting ahead of my future self post but just a heads up if you were looking to buy extra wheel collars. The Shars are excellent. Less that 0.001" runout on any surface. They offer a 0.750 & 1.250" OD shank, coarser thread pitch but same nominal M18. They look ground or at least precision machined on all surfaces including spacer/washers. Much, much better quality than the single one kitted with my Accusize unit (who can't seem to understand why, or be bothered to stock any despite phone calls). However the Shars D-bit spindle is a 1:5 taper ratio, my spindle is 1:10 so obviously don't fit. But I decided the Shars were well worth the effort to bore & lap the required taper, so now they fit perfect. I'm starting to get a vibe they are more prescriptive of their machines from factory, so be a bit cautious when you see what everyoe assumes is the exact same thing. To be continued....

 

[Former Member]

I bought the Shars, saw the Vertex at a distributors here in Mississauga, and considered the Accusize.

Vertex, limited collet availability, similar to the original Deckels.
Accusize R8, better but still limits options.
Shars, 5C from the get go (purchased and imported during COVID) and order grind wheel adapters, a full 5C collet set from Accusize.

Haven't yet used it to its full potential but am very impressed with over fit and finish. I have figured out how to split points and center cutting end mills. Secret is the style of grinding wheel to achieve the cuts along with a bit of skill. It is on the list to video it so that others can do it.

Another source is ASC365.com in Toronto, they have various options...be selective.

Shars has the lowest cost wheel selection, specialty wheel can cost $300 and up with the right geometry for the required cuts.

 

[140mower]

Hmmm, my Alexander is .925 at it's widest. While not ideal, it's easier than putting it back on..... I think when the time comes to move it up the project list, I am going to attempt making collets first before I dive in and consider this as a rough casting that needs machining to fit. Although, the larger capacity of the 5c would be nice.

 

[PeterT]

I'd use the dovetail 'at its widest' as a relatively coarse measurement. In reality the edges are chamfered as they should be, so it doesn't represent the point to point dimension. If you wanted better dimensions, best to measure using 2 dowels etc. But its close enough for what I was after. On the Asian machines I've seen, there is a healthy thick gib strip (which I will re-make) So as long as the Shars 5C heads are nominally the same dovetail as my Accusize, they should be adaptable. One could even mill the entire male dovetail off & bolt on a self-made one sized to fit for that matter, they are standard 60-deg angles. These dovetails don't see high loads or require tool repeatability like a lathe tool post dovetail. Just an accurate sliding fit (which it is not at present). I'm throwing good money after bad on this unit, but oh well.

The 5C issue is kind of 'depends'. If you don't already have a full set of 5C collets, there may be better options. Arguably an ER would give you more diameter holding capability with fewer collets. An ER holding shank can be had very reasonably priced, but it would have to be bored in order to have the capacity to hold anything of length similar to R8 or 5C collet ID. Or you machine your own ER fixture from scratch which requires the proper angle seat, threads etc. Even so, the ER nut size may not play nice in close proximity to the grinding wheel depending on stick-out & swing & all those variables you may want to do with TCG. You want to minimize stick out as much as possible.

On the

 

[Former Member]

The issue with these grinders is the pivot point locations which limits range of motion on larger cutters. A ER32 would be a good option but because of the machine design the 5C is likely the best.

A good thing is that strong grip is not required just accurate and firm grip playing into the hands of the 5C.

In my case I decided 5C was the standard to use and got the same for the lathe and sq and octagon holders since I was expanding my tool set.

 

[PeterT]

I actually don't think there is much difference between R8 & 5C collet as a design standard. They both grip accurately, both have similar low profile nose profile between end of collet & wheel. Both are more common to purchase vs. the original Deckel / U-format, although those are now remanufactured in China within nominal (metric only?) sizes. All these collets by their nature only grip diameters within a narrow range slightly less than their nominal. They were not really intended to grip everything & anything. The D-bits were made from nominal diameter stock or tooling shanks. If you want to grip narrow gradations, say drill sizes, you are probably looking at a 1/64" or 0.5mm step collet set anyways unless you go ER. I think that's where the Vee block / clamp fixture comes in. It theoretically holds any size, but it is a clunky device. Mine looks like blacksmith tooling.

The work head does not allow any tool/stock to protrude out the end because its blocked by the tightening handle, so tool length is confined to ~ typical collet length capacity. The other tool head aka 'end mill sharpener' will allow longer stock inside the barrel. Its more like a spin tube. But it has no indexing/detent like the main work head. At least mine doesn't. That may be an other variation to Shars from what I can see of manual, so TBD). It is meant to be guided by a finger like along an end mill or drill OD helix sharpening the outside edges. But I don't think that has any equivalent purpose on the front cutting edges of a drill.

Its not that R8 choice is bad, its just that IMO they kind of botched the implementation on a few fronts. I'll show more about this when the time comes but for now I'm shifting focus to 5C conversion.

Accusize end mill sharpener

 

[Former Member]

The issue with both to achieve a good accurate grip is to remain within a very specific limit of grip of which both are actually very narrow. The advantage with the 5C is there are significantly more readily sizes (both larger, smaller and shapes) available. This is primarily what drove my decision.

To be fair in grip strength I would lean towards the R8.

The final factor is the 5C is threaded both inside and out which in therms of length allows sticking material through the 5C which is not possible in R8.

To further confuse the issue the ER style covers all these advantages/disadvantages with one exception that the Nut is upfront which causes clearance issues and projection.

 

[PeterT]

The final factor is the 5C is threaded both inside and out which in therms of length allows sticking material through the 5C which is not possible in R8.

Yes the 5C collet itself is dual threaded, but specific to Shars TCG, isn't both the work head & end mill sharpening 'spin' tube blocked from anything exiting past the rear handle because its threaded to the internal 5C threads? I don't think you can access the external threads, they are immediately adjacent to to tube. Am I missing something?

 

[Former Member]

Have to double check here before commenting.

 

[PeterT]

The issue with both to achieve a good accurate grip is to remain within a very specific limit of grip of which both are actually very narrow.

Not quite sure what you are getting at here. An R8 can hold an endmill in a milling machine, but can't hold a tool shank in a much lower torque TCG grinding setup? I recognize holding drill flutes is reduced contact area, but my logic is R8 & 5C bcollet th superseded the original Deckel U collet which lasted for +60 years, with arguably similar contact area & fit, so what's the difference?

 

[Former Member]

As the these 3 collet types U, R8, 5C) pinch to hold and grip the interior surface of the collet actually starts to taper so that it allows a bit to wobble. Again within their range it is not an issue but as to range increases the problem starts to show itself.

Better descriptions of all this can be found in older machinist text books.

 

[PeterT]

Yup, I'm familiar with the general collet work holding principles & I use both 5C & R8 regularly in different assemblies. But gripping a tool shank in TCG isn't really different than gripping a part or tool in a collet chuck or arbor. You must stay within the size limits of the collet regardless.

I'll show a pic later but where the Accusize TCG variant kind of messed up IMO is retrofitting the spin tube / end mill fixture. A healthy portion of the R8 is sticking out proud of the nose, unsupported by the taper seat. They should have machined that properly. Thankfully its not the case on the R8 work head. I think they also skipped over some of the finger holding features, at least it looks different to others. Moral of the story is, these machines are not created equal. Buyer Beware.

 

[Former Member]

On the SHARS the Flute fixture allows a complete thru mount, the face fixture does not. The reason for this is there are several stops and locks to index the rotation once set correctly for accurate grinds. The only drawback with the various preset indexes is that they are set on equally space flute locations, high performance endmills are now coming with variable spaced flutes which are not equally spaced to improve finishes by reducing vibrations.

I have not seen the Accusize version, but I have seen the Vertex version which is good build quality.

@PeterT I would contact Accusize with your concern and I would not be surprised if they change the head for you, thier after sales service is very good from my experience.

 

[PeterT]

I've called Accusize on a few occasions re the TCG. For example they show a 5C TCG machine separate to the R8 in a different color. But its not actually a 5C. Its a different package of tooling. So why put 5C in the description? Borrowed factory picture? I asked specifically about them working with their factory/contacts about getting me 5C work heads, answer = no. I've called & emailed a few times about getting wheel collars which they do not stock & is actually very important a) because you want to marry a wheel to a collar so as not to redress every time you mount it b) because their flavor of spindle is a different taper. That was months ago, again, no progress. So I bought them from Shars. Which in hindsight is where I should have got the machine itself & saved me the headaches & expense. Yes, overall they were very polite, but that didn't do me any good in the parts department.

The Vertex might be the upscale one that used to be around. If it was made in Taiwan for sure. It is more than double the price of Chinese versions. I have it on good authority the Shars is a few notches above Accusize, but I will be in a better position to judge shortly. the Grizzly 'may' have been a Taiwan machine but not sure there & they no longer sell last time I checked.

 

[PeterT]

On the SHARS the Flute fixture allows a complete thru mount, the face fixture does not. The reason for this is there are several stops and locks to index the rotation once set correctly for accurate grinds. The only drawback with the various preset indexes is that they are set on equally space flute locations, high performance endmills are now coming with variable spaced flutes which are not equally spaced to improve finishes by reducing vibrations.

I'm not following you here. The flute fixture / end mill fixture / spin fixture relies on a finger attachment to guide the helical path advancement for grinding the side flute of EM. So it doesn't matter what the helix shape or pitch or helix count is. It just follows along the flute once engaged. The other fixture, the work head, has 3 modes: detent stop every X degrees, detent stop about 180-deg, no detent full rotational spin but no axial action in any of these modes. You can't do the sides of an EM with the work head AFAIK, it wasn't designed for this. You can do the ends of an end mil, or facets of a drill, or edges of a cutter at any angle, or any of those ops. Am I missing something?

 

[Former Member]

You can also do the center cutting, but it does require a particular wheel (diamond shaped) and some fine alignment.

While the machine wasn't designed for doing certain things all it requires is have the right wheel and correct (inventive) approach. The sad part is all of the research I've done hints at some of these things, but few are document let alone well documented.

One of my goals is to do some documention as I progress.

 

[Former Member]

Both fixtures allow you to spin, though one has stops, the other has none but allows for fore and aft movement as it rotates. This is for the flutes (sides of the endmill) to allow refreshing or custom sizing (smaller) off an exist endmill).

Sad part is that it does not have spiral to all grinding of new endmills (old school).

For the price even, new very versatile though poorly documented in all the operations possible.

There is also a YouTube series that document and upsizing of range to allow better work angles.