# Rebuilding a DTM 75A (BXA) tool post ...



## wquiles (Dec 23, 2009)

I recently bought this used/damaged DTM 75A (BXA size) wedge style tool post on Ebay with missing parts and wedges:












Once you unscrew the main piece you get to see more of how it looks on the inside:











Here I am about to clean the parts:






and after cleaning them:




































(I am including extra pictures to make sure that I give Barry's new computer a good workout )


The reason I purchased this poor looking tool post is because Michael had all of the parts available to repair it at a very reasonable cost:






Assembling the tool post is very easy, except for one thing: the wedges were oversized and hardened. Not only Michael provided me with parts, but he also took photos of his fitted wedges (he also has one 75A) against the new ones, which allowed me to know before hand what needed to be cut/fitted.

Michael did warn me that I needed a surface grinder (one of these days Barry ...), but I decided to do it by hand anyway, which unfortunately meant using mostly a hand diamond file (my good files would not even bite on the wedges). I also used a sharpening stone to polish some edges:






The other reason to using a surface grinder is that I could had made the wedges perfectly flat - they were not:











As you can imagine with a hardened wedge against a hardened body, it was a slow process. The slot was not perfectly uniform either as I could not slide the same portion of the wedge top to bottom:











So I took this advantage to also smooth out the machining marks inside of the sliding surfaces for the wedges:






After many hours, I got both wedges to slide in, but with no lateral play:











I also rounded all corners, and made sure the the keys that hold the wedge in place did not bind anywhere:











This is how the wedge looks in place:






Here are the wedges at the top-most position:






and at the down position:






(Barry, the new computer has not chocked up yet, right? I hope not, since I am not quite done yet )


Now came the tough problem which Michael warned me about - the wedges had to be trimmed to adjust for the tool holder (remember they are over-sized). At first try, the tool holder would not go all of the way down:






From my various BXA tool holders, I found 3 to use for reference:
- loose fitting: cheap Asian tool holder:






- good fitting: Aloris 5C collet holder






- tight fitting: WQ designed/built 1" BXA tool holder






Here is a group photo:






One of the two wedges needed some trimming, but the other one needed a LOT  -> bad wedge, bad wedge :whoopin:


One of the areas that was not quite obvious was this inner surface:






If this was not lower than the ground surface, the tool holder would not be even. I tested by pushing this guide and grinding until it would more freely:






If it was not quite enough, when you install the tool holder, you can see a little bit of light between the tool holder and the block - this is what I am trying to eliminate. Very slow and tedious process due to the hardness of the wedges:






For the wedge that needed a lot of metal removed, I "cheated" and used a small 1" sander to get the majority of the metal, but then had to still smooth and align by using the diamond file:











It was great when I finally was able to get the tool holders to fit properly on both sides of the tool post:






I then took apart, cleaned, lubed with way oil, and re-assembled:


























(OK, Barry, that was the last picture - I hope your new PC did pass this "torture" test with flying colors!).


The wedges have no side to side movement, but due to the design of the wedge, it does more sligthly up and down some, and in/out some (the guides are not fitted parts). I think this is part of the design to allow some movement/adjustment of the wedge to lock in place. The only small negative that I see to fitting the wedges by hand is that the edge of the wedge that meets the tool holder is not "perfectly" matting with the tool holder top to bottom, although the lock-up is "very" solid as it stands right now - much more nicer than my year-old Phase II wedge tool post - not even in the same league. I am now waiting to receive from Michael the new "T" so that I can mill/fit to my lathe, so that I can try it for good and see how good/tight the "restored" DTM tool post works out.

I have to admit that Michael was right - this job was too tedious to do by hand without a surface grinder, but even with one, the inner fitting on some surfaces needed to be done by hand anyway, so this job took far longer than I anticipated. One thing is for sure - after these many hours, the price of the new Dorian triple wedge does not look so high right about now :devil:

Will


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## precisionworks (Dec 23, 2009)

Americans & Europeans used to do that type of work every day, sitting at a bench, usually on steel yet to be hardened. After initial fitting, the parts were hardened, which almost always causes slight warping, so the parts were then "stoned in" for a final fit. Very few companies today hand fit anything. 

Nice job :thumbsup:



> the price of the new Dorian triple wedge does not look so high right about now


Funny, but those were exactly my thoughts as I looked at photo #67 

Any ground product is going to be pricey, whether it's the Dorian triple wedge, a Kurt vise, or adjustable parallels from Brown & Sharpe. Even though a CNC grinder is used, it's a slow process & the price reflects the time involved.

$250 will probably buy eBay item number 320463989039, and shipping shouldn't be a deal breaker. Or, if you decide to drive to Chicago you'll go right past my shop, so you might as well stop in for a day or two.


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## cmacclel (Dec 23, 2009)

Will you have way to much time on your hands  You could have built a couple of lights and bought a brand new Dorian in the same amount of time 


Mac


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## wquiles (Dec 24, 2009)

Thanks Barry. I need to make room for a small grinder - one of these days 


Mac - No quite. My son had surgery and has been recuperating for the last couple of weeks, so I had no time for new projects, and no time on the lathe/mill (first time in a year that I have not used the lathe for several weeks in a row), but I had an hour here and there to work on fitting the wedges. That is why it has taken 3-4 weeks to get this project completed.

Will


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## StrikerDown (Dec 24, 2009)

wquiles said:


> Will



Great job as usual Will!

Who makes the belt sander?

Belts?

I have an older HF belt with the 6" disk on the side. It is kinda wimpy and the belts don't have a very smooth transition an the point where the ends are joined. Works file for wood but metal makes for a bumpy ride!


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## wquiles (Dec 24, 2009)

StrikerDown said:


> Great job as usual Will!
> 
> Who makes the belt sander?
> 
> ...


Enco 1" by 30" belt sander. Item # 163-4831. On special right now for $68
link to Enco item ...

Mine is probably similar to yours in its behavior, but I needed something less aggressive than the bench grinder, and this fits the bill for something that will see little use, but be there for those odd jobs. Tell you what, I am happy I had it for those wedges!

Will


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## gadget_lover (Dec 25, 2009)

Ray,

You can get replacement belts from Home Depot and Lowes if you can't find them anywhere else. There is no reason for them to have a bump at the overlap.

Daniel


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## StrikerDown (Dec 25, 2009)

gadget_lover said:


> Ray,
> 
> You can get replacement belts from Home Depot and Lowes if you can't find them anywhere else. There is no reason for them to have a bump at the overlap.
> 
> Daniel



You mean that some place might have better quality stuff than HF! 

I thought they all had the bump even the belts I picked up from Sears (craftsman) have a bump, although they are better than HF stuff.

What brand should I try?


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## wquiles (Dec 30, 2009)

I got the "T" to fit for my lathe, and the two new o-rings:






On top the new T for the DTM tool post (not yet fitted) and the fitted piece from the Phase II tool post:











Comparing DTM (Left) and Phase II (Right):






The new T piece is just a little tall:






Getting ready to cut:






done with the mill part (at least per my measurements):






Not quite, but very close:






since this part is not hardened, it was very easy to file it to fit:





















I then used a straight carbide bar to align the tool post to the spindle of the lathe:






Now I have to double check/adjust the tools to make sure they are still on center, but at least I can start using it for good 

Will


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## cmacclel (Dec 30, 2009)

Will when I tram in the toolpost I install a piece of 1" drill rod into the chuck and then put the magnetic indicator block onto the 1" drill rod and then indicate the toolpost.

Mac


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## wquiles (Dec 30, 2009)

cmacclel said:


> Will when I tram in the toolpost I install a piece of 1" drill rod into the chuck and then put the magnetic indicator block onto the 1" drill rod and then indicate the toolpost.
> 
> Mac



The way I did it, as I move the carriage to/from the chuck, since the indicator is fixed to the ways, I can see if the boring bar is parallel or not to the ways, over the 8 inches or so that I check. I then keep aligning the tool post over the 8 inches until I have about 0.0002" variation/taper across the 8 inches, so I stopped and called it day. 

How exactly do you "indicate" the tool post with your method? I need a visual aid


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## darkzero (Jan 30, 2010)

Will, look what I cam across. http://www.spotovi.org/rebuilding-a-dtm-75a-bxa-tool-post

:thinking:

Just wondering if someone stole your post? Well it does reference CPF at the bottom of the page.


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## PEU (Jan 30, 2010)

Its one of these sites that appears to be informational but just rips content elsewhere to have it surrounded by ads. Im not sure if Will is using a photo hosting site, but that page hotlinks every photo, if I were using my own server I would use an htaccess setting to replace hotlinked images with something else 


Pablo


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## wquiles (Jan 30, 2010)

darkzero said:


> Will, look what I cam across. http://www.spotovi.org/rebuilding-a-dtm-75a-bxa-tool-post
> 
> :thinking:
> 
> Just wondering if someone stole your post? Well it does reference CPF at the bottom of the page.






PEU said:


> Its one of these sites that appears to be informational but just rips content elsewhere to have it surrounded by ads. Im not sure if Will is using a photo hosting site, but that page hotlinks every photo, if I were using my own server I would use an htaccess setting to replace hotlinked images with something else
> 
> 
> Pablo



Yes, that is my work, and yup, they just lifted the complete post and stole and hotlinked the content. Weird :shakehead


On the other hand, I must say that I am incredibly impressed with the repaired tool post. It has a short arc of motion, it is very smooth, and it locks up very solid, very tight. Barry once use the description of "bank vault" when describing the good tool posts - that is how mine feels now. Now I know what he meant


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## PEU (Jan 30, 2010)

if you let me choose between a loaded toolpost and a loaded bank vault... I would choose the vault :nana:


Pablo


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## gadget_lover (Jan 30, 2010)

wquiles said:


> Yes, that is my work, and yup, they just lifted the complete post and stole and hotlinked the content. Weird :shakehead



Well, on the one hand, you posted it to share the experience with the world. Google apparently has a feed from CPF (yes, they accept commercial feeds to their search engine database) so everything you post is really for world wide consumption. I suspect Sasha set up a feed since I often see very recent(1 hour old posts) in google.

On the other hand, it would be nice if there were credit being given for all the work you put into your posts.

On the third hand, I always find it to be a complement when someone likes my work enough to plagiarizer it for build on it. 

Daniel


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## wquiles (Jan 30, 2010)

gadget_lover said:


> Well, on the one hand, you posted it to share the experience with the world. Google apparently has a feed from CPF (yes, they accept commercial feeds to their search engine database) so everything you post is really for world wide consumption. I suspect Sasha set up a feed since I often see very recent(1 hour old posts) in google.
> 
> On the other hand, it would be nice if there were credit being given for all the work you put into your posts.
> 
> ...




It is not the first time it happens to me. I have had folks re-post work that I have done (I do the same detailed, step-by-step for all projects I do, including car repair/modifications/etc.), but usually they do ask and they do host the content themselves, and of course they do credit me with the work.

I post these projects that I do to share with everyone, so I am not angry, just disappointed as to how it was done, specially when the content was hot-linked using my own server resources 

But like you said, somebody thought it was interesting enough to re-post, so hopefully it will be of help to somebody else outside out small community.


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## ICUDoc (Jan 30, 2010)

Great original post and great attitude wquiles.
Do you think you might make a new T-piece that is as wide as the toolslide? I note that a few aftermarket mods (eg as supplied by Grizzly, LMS, others) use a narrower T but I think it would LOOK stronger if it went all the way across!!! As you say it's a bank vault already, so it's probably overkill....


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## darkzero (Jan 30, 2010)

wquiles said:


> Yes, that is my work, and yup, they just lifted the complete post and stole and hotlinked the content. Weird :shakehead


 
Oh man, that is weird! I'll keep an eye out for any more of your pictorials. 



wquiles said:


> On the other hand, I must say that I am incredibly impressed with the repaired tool post. It has a shortr arc of motion, it is very smooth, and it locks up very solid, very tight. Barry once use the description of "bank vault" when describing the good tool posts - that is how mine feels now. Now I know what he meant


 
With the amount of fine detailed work & long hours you put into it I have no doubt in my mind that it is now a great working TP! After all I do have a DTM 65A that I originally bought for the PM1127-VF I originally purchased. I was so excited to use it as I really liked every aspect of it. 

It's unfortunate that I did not get to use it as well as not having any luck selling it but just having the 1236 now more than makes up for it. Although I may never use it I'm in no desperate need to sell it. Who knows, maybe it might come in handy some day if it never sells.

It's great that you feel that way I think you still deserve credit by mentioning your name on that site.  I have not looked but I wonder if all the other content on that site is the same way with no mention of the original author.


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## wquiles (Jan 30, 2010)

ICUDoc said:


> Great original post and great attitude wquiles.
> Do you think you might make a new T-piece that is as wide as the toolslide? I note that a few aftermarket mods (eg as supplied by Grizzly, LMS, others) use a narrower T but I think it would LOOK stronger if it went all the way across!!! As you say it's a bank vault already, so it's probably overkill....


I have to admit I was disapointed in how "small" the block was. However, after month of use, it has not moved at all, so maybe this is enough and anything larger is just an overkill 




darkzero said:


> Oh man, that is weird! I'll keep an eye out for any more of your pictorials.



Here are some of the most popular. You can take a look at when you have some free time (the first one is an "oldie" from 2002 - even 8 years after that post I was still getting thank you emails and follow-up questions):
DIY post - Full H&K Audio Upgrade (long!)

DICE iPod and XM install on E39 with DSP (no 56K)

540 Zionsville HD Install DIY with photos (no 56K)

Improvement for Zionsville rad with electric fan

DIY for replacing headlight covers/adjusters

3rd ATF Fluid Analysis arrived ... (469 views) (1443 thread views)


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## madbee (Feb 21, 2010)

Hi darkzero, I was researching Tool Posts and noticed you once had the DTM for sale. Is it still available?
Thanks.



darkzero said:


> After all I do have a DTM 65A that I originally bought for the PM1127-VF I originally purchased. I was so excited to use it as I really liked every aspect of it.
> 
> It's unfortunate that I did not get to use it as well as not having any luck selling it but just having the 1236 now more than makes up for it. Although I may never use it I'm in no desperate need to sell it. Who knows, maybe it might come in handy some day if it never sells.


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## darkzero (Feb 21, 2010)

madbee said:


> Hi darkzero, I was researching Tool Posts and noticed you once had the DTM for sale. Is it still available?
> Thanks.


 
Yes I do still have it. New never used & complete with the blank T. It's the TP65A / AXA size. Just so we don't clutter up Will's (wquiles) thread, please PM me or send me an email to the addy listed in my profile if interested.

Thanks

Will


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