Author Topic: Floating Reamer Holders  (Read 12648 times)

Offline Roger B

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Re: Floating Reamer Holders
« Reply #15 on: November 08, 2016, 05:27:05 PM »
Charlie, A nice tool  :ThumbsUp:  :ThumbsUp: , have you tried it with small reamers? What size is the taper?
Best regards

Roger

Offline Tennessee Whiskey

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Re: Floating Reamer Holders
« Reply #16 on: November 08, 2016, 07:29:23 PM »
I think Chuck Fellows purchased a floating reamer holder from one of our gunsmith supply houses on this side of the pond,  perhaps you have an equivalent.

Cletus

Offline Roger B

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Re: Floating Reamer Holders
« Reply #17 on: November 08, 2016, 08:33:20 PM »
Thank you Cletus  :ThumbsUp:

I had a search on some gunsmiths suppliers. In the UK guns are pretty well a no go area, in mainland Europe it's a bit easier. There is a Swiss branch of a US supplier which offers a Manson floating reamer holder. It looks a bit bigger than I need and would require an MT 1 shank to be made. I will look further into Manson Precision.

http://www.brownells.ch/epages/Switzerland.sf/de_CH/?ObjectID=55053
Best regards

Roger

Offline cwelkie

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Re: Floating Reamer Holders
« Reply #18 on: November 09, 2016, 02:49:36 AM »
Thanks for the kind comments.
Roger - it's an MT3 taper.  Just used a "blank-head" arbor as a starting point.
Cheers
Cw

Offline Chipswitheverything

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Re: Floating Reamer Holders
« Reply #19 on: November 09, 2016, 09:20:18 AM »
Interesting discussion and very helpful photos of the various tooling items.
 But Roger, if you are mostly wanting to use a floating holder on the very small diameter , c.  1.5mm reamers that you indicate, will the reamers have any stiffness sufficient to exert a centering action upon the spring loaded and perhaps fairly stiff action of the typical floating holders?  I do wonder if a reamer of, maybe, 4mm or more is needed before this happens.
 Don't know what machinery you are using, but Is the alignment of your lathe headstock to tailstock actually far enough out to concern you when reaming small sizes?  Or could you make some improvement to the alignment, check the tailstock set over carefully for instance?  Another idea that occurs is to make a little holding bush for the reamer shank, held in the tailstock, (in chuck or better, directly in the taper ), and drilled and reamed (!) in situ from the headstock.  If it was a taper shank, it could be marked to be re-align able for subsequent removal and re insertion...   Dave

Offline Roger B

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Re: Floating Reamer Holders
« Reply #20 on: November 09, 2016, 11:17:34 AM »
Thank you Dave  :ThumbsUp:

The answer to most of it is I don't know but am trying to learn  :headscratch:  :headscratch:

My lathe is a Hobbymat with a D shaped bed so there is no easy way to adjust the tailstock. I don't think that it is too far out for general use, but from what I understand when reaming the alignment should be better than the tolerance you are expecting, hence the need for floating holders.

There appears to be several types of floating holder, some just allow for axial misalignment like Jo's Clarkson and the Manson unit from the gunsmith website. Other versions also compensate for angular misalignment in various ways.

Do I need to compensate for angular misalignment? I don't know, but as I am drilling some quite deep small holes, 2mm dia 20mm deep, it is quite likely that the drill will wander.

Most of the holders are obviously too big and heavy for my requirements. The small sized ones I have found do specify a range, typically 1-7mm diameter reamers often using ER11 collets so I have to assume that the spring tension range (adjustable on some units) is appropriate for these sizes.

This is certainly an interesting learning experience and once again I thank everyone for their support and interest.
« Last Edit: November 10, 2016, 07:00:45 PM by Roger B »
Best regards

Roger

Offline Dan Rowe

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Re: Floating Reamer Holders
« Reply #21 on: November 09, 2016, 02:20:31 PM »
Roger,
I have been following this topic with interest. I do not have any answers just learning like you. I found a floating holder that has spring pressure adjustment for both types of misalignment with a drawing and explanation of use.
http://batzberg-manufaktur.ch/documents/Floating%20Reamer%20Holder.pdf

Dan
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Offline engjas

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Re: Floating Reamer Holders
« Reply #22 on: November 10, 2016, 09:48:43 AM »
Hello Roger
I too have been interested in this topic sufficiently so to have spent a few pleasurable moments looking up old patents for such devices. Several are variations on what I recognise as the "oldham" coupling, others use rubber as the flexible element along with springs, some of the more simpler devices utilise spring loaded spherical elements. All very interesting. Have a look on Google Patents.

However the pragmatist in me wonders if you are attempting to solve a problem that might not exist or possibly not as bad as you would believe. Have you actually tried to ream your 2.0 mm by 20 deep hole and measured the result? Could you measure (detect) any error?

From the patents information it might be possible, but I've not tried, to grip a 2mm reamer inside a rubber tube (say something like bunsen burner gas tube) inside a tailstock (Jacobs) chuck sufficiently to cut but yet be flexible enough to float a little.

Some times a change of approach can also give better results. For instance if concentricity is a real issue or exact location then is it possible to put the hole in first and then manufacture the outside to suit? I recall an article years ago by Professor Denis chaddock titled putting the cart before the hores wherein he outlined machining of a crankcase for an IC engine from a cube staring with all the important holes and whittling the outside to shape llater.

Sorry not to have any real answers just my two pence (cents)worth.

Good luck and please let us all know how you get on.

John

Offline Roger B

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Re: Floating Reamer Holders
« Reply #23 on: November 10, 2016, 11:42:46 AM »
Thank you Dan  :ThumbsUp: Batzberg produce the Angst floating holder I mentioned earlier. Their MT1-ER11 unit would suit admirably except for the price  :(

John, I am not quite sure how real the problem is  :headscratch: This relates to my fuel injection system experiments:

http://www.modelenginemaker.com/index.php/topic,4906.0.html

I have already made a number of trial pieces by drilling, reaming and lapping. The better the finish and accuracy after reaming is the better chance I have of reaching my (sub?) micron target. For the injection pump position and concentricity are not critical, just the quality of the bore. For the injector itself the bore needs to be concentric with the nozzle hole but I have resolved this by using the bore to guide the nozzle drill and seat cutter.

I think that a floating reamer holder will help, but I need to invest either significant workshop time or money to find out  ::) There is very little information available on how others have solved this problem.

Best regards

Roger

Offline Dan Rowe

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Re: Floating Reamer Holders
« Reply #24 on: November 10, 2016, 03:48:21 PM »
Roger,
Now that you have explained what you are trying to accomplish have you considered ballizing? A funny word for pressing a precise carbide ball in a slightly undersized hole.
http://nationalballomatic.com/basics.php

I have not tried this but I found it interesting and low cost.

Dan
ShaylocoDan

Offline Roger B

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Re: Floating Reamer Holders
« Reply #25 on: November 10, 2016, 05:42:07 PM »
Thank you again Dan  :ThumbsUp: I am aware of 'ballizing'. It was mentioned on here a couple of years ago when Hobbynut was having problems with the injection system for his Lister 6/1:

http://www.modelenginemaker.com/index.php/topic,1742.225.html

I don't know how he got on, but it seemed to me that the hole had to be extremely straight and true before this technique would work. I ended up with one banana shaped bore where the pin gauge would enter more than halfway from both ends but would not go through  ::)
Best regards

Roger

Offline Roger B

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Re: Floating Reamer Holders
« Reply #26 on: November 12, 2016, 06:24:06 PM »
I have an injection pump body that I had reamed but not yet lapped. It was drilled 1.7mm then reamed 1.95mm. I have a 1.97mm pin gauge that will go into that starting end 4 or 5mm and a couple of mm into the leaving end. The 1.98 mm pin gauge will just enter the starting end so there is from my viewpoint significant bellmouthing. The target after lapping is 1.98mm (2mm silver steel hardened and then lapped).
The picture is of a previously lapped pump body. It's from 10mm square bar stock.
Best regards

Roger

Offline Roger B

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Re: Floating Reamer Holders
« Reply #27 on: March 22, 2017, 07:48:30 PM »
I had another go at this. The tailstock on my Hobbymat is split so the sleeve can be clamped. I had made another pump body and this time for reaming I tightened the clamp as far as possible to reduce any movement of the tailstock chuck.
The result was that after reaming 1.95mm the 1.97mm pin gauge passed straight through and the 1.98mm gauge would enter significantly from both ends. This was worse that leaving the clamp loose.
I think that I need to spend some money on a floating reamer holder  :headscratch:
Best regards

Roger

Offline Roger B

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Re: Floating Reamer Holders
« Reply #28 on: April 23, 2017, 07:40:16 PM »
I finally decided to buy an Angst floating reamer holder. The MT1 version was no longer available so I got one with a 14mm dia 25mm long stub and a soft end MT1 arbour.

The arbour was bored out to fit and then I tried some experiments. I used the same 10mm square black bar that I use for the pumps and injectors, but without spending time on the offset turning.

For the first trial I center drilled quite deep, set the side centering force to minimum and left the pendulum adjustment in the middle. The hole was drilled 1.8 mm at 2000rpm and them reamed 1.95mm at 500rpm (same for all trials).

In this case the 1.97 pin gauge would not enter from the exit end but went in around 4mm from the entry end.

I tried again with a smaller center drilling and got similar results. I then tried with a smaller drill chuck (3mm max) to reduce the overhang and adjusted the pendulum resistance to maximum. This was worse, the 1.97 pin gauge would enter around 6mm and I could feel a jolt as the reamer entered.

I them adjusted the pendulum resistance to absolute minimum (last thread on the screw) and tried again. This time the 1.97 pin gauge would enter less than 2mm.

There is definitely something in this  :headscratch: Is the floating holder worth it? I think it may be if I am doing a lot of injector work, but I need a few more pin gauges to confirm.

As ever the bores can be corrected by lapping, but the better the bores are to start with the quicker you will reach a good finish.
Best regards

Roger

Offline Admiral_dk

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Re: Floating Reamer Holders
« Reply #29 on: April 23, 2017, 09:45:48 PM »
We continue to wish that you will succeed with your endeavour - but I must admit, that I'm not sure if you end up with a recommendation or not .....

 

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